55820e298a
spinlocks.
2811 lines
77 KiB
C
2811 lines
77 KiB
C
/*-
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* Copyright (c) 2008 Isilon Systems, Inc.
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* Copyright (c) 2008 Ilya Maykov <ivmaykov@gmail.com>
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* Copyright (c) 1998 Berkeley Software Design, Inc.
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* All rights reserved.
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*
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* Redistribution and use in source and binary forms, with or without
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* modification, are permitted provided that the following conditions
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* are met:
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* 1. Redistributions of source code must retain the above copyright
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* notice, this list of conditions and the following disclaimer.
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* 2. Redistributions in binary form must reproduce the above copyright
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* notice, this list of conditions and the following disclaimer in the
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* documentation and/or other materials provided with the distribution.
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* 3. Berkeley Software Design Inc's name may not be used to endorse or
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* promote products derived from this software without specific prior
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* written permission.
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*
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* THIS SOFTWARE IS PROVIDED BY BERKELEY SOFTWARE DESIGN INC ``AS IS'' AND
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* ANY EXPRESS OR IMPLIED WARRANTIES, INCLUDING, BUT NOT LIMITED TO, THE
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* IMPLIED WARRANTIES OF MERCHANTABILITY AND FITNESS FOR A PARTICULAR PURPOSE
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* ARE DISCLAIMED. IN NO EVENT SHALL BERKELEY SOFTWARE DESIGN INC BE LIABLE
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* FOR ANY DIRECT, INDIRECT, INCIDENTAL, SPECIAL, EXEMPLARY, OR CONSEQUENTIAL
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* DAMAGES (INCLUDING, BUT NOT LIMITED TO, PROCUREMENT OF SUBSTITUTE GOODS
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* OR SERVICES; LOSS OF USE, DATA, OR PROFITS; OR BUSINESS INTERRUPTION)
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* HOWEVER CAUSED AND ON ANY THEORY OF LIABILITY, WHETHER IN CONTRACT, STRICT
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* LIABILITY, OR TORT (INCLUDING NEGLIGENCE OR OTHERWISE) ARISING IN ANY WAY
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* OUT OF THE USE OF THIS SOFTWARE, EVEN IF ADVISED OF THE POSSIBILITY OF
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* SUCH DAMAGE.
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*
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* from BSDI $Id: mutex_witness.c,v 1.1.2.20 2000/04/27 03:10:27 cp Exp $
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* and BSDI $Id: synch_machdep.c,v 2.3.2.39 2000/04/27 03:10:25 cp Exp $
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*/
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/*
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* Implementation of the `witness' lock verifier. Originally implemented for
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* mutexes in BSD/OS. Extended to handle generic lock objects and lock
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* classes in FreeBSD.
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*/
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/*
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* Main Entry: witness
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* Pronunciation: 'wit-n&s
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* Function: noun
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* Etymology: Middle English witnesse, from Old English witnes knowledge,
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* testimony, witness, from 2wit
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* Date: before 12th century
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* 1 : attestation of a fact or event : TESTIMONY
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* 2 : one that gives evidence; specifically : one who testifies in
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* a cause or before a judicial tribunal
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* 3 : one asked to be present at a transaction so as to be able to
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* testify to its having taken place
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* 4 : one who has personal knowledge of something
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* 5 a : something serving as evidence or proof : SIGN
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* b : public affirmation by word or example of usually
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* religious faith or conviction <the heroic witness to divine
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* life -- Pilot>
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* 6 capitalized : a member of the Jehovah's Witnesses
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*/
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/*
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* Special rules concerning Giant and lock orders:
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*
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* 1) Giant must be acquired before any other mutexes. Stated another way,
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* no other mutex may be held when Giant is acquired.
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*
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* 2) Giant must be released when blocking on a sleepable lock.
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*
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* This rule is less obvious, but is a result of Giant providing the same
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* semantics as spl(). Basically, when a thread sleeps, it must release
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* Giant. When a thread blocks on a sleepable lock, it sleeps. Hence rule
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* 2).
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*
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* 3) Giant may be acquired before or after sleepable locks.
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*
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* This rule is also not quite as obvious. Giant may be acquired after
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* a sleepable lock because it is a non-sleepable lock and non-sleepable
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* locks may always be acquired while holding a sleepable lock. The second
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* case, Giant before a sleepable lock, follows from rule 2) above. Suppose
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* you have two threads T1 and T2 and a sleepable lock X. Suppose that T1
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* acquires X and blocks on Giant. Then suppose that T2 acquires Giant and
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* blocks on X. When T2 blocks on X, T2 will release Giant allowing T1 to
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* execute. Thus, acquiring Giant both before and after a sleepable lock
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* will not result in a lock order reversal.
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*/
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#include <sys/cdefs.h>
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__FBSDID("$FreeBSD$");
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#include "opt_ddb.h"
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#include "opt_hwpmc_hooks.h"
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#include "opt_stack.h"
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#include "opt_witness.h"
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#include <sys/param.h>
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#include <sys/bus.h>
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#include <sys/kdb.h>
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#include <sys/kernel.h>
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#include <sys/ktr.h>
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#include <sys/lock.h>
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#include <sys/malloc.h>
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#include <sys/mutex.h>
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#include <sys/priv.h>
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#include <sys/proc.h>
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#include <sys/sbuf.h>
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#include <sys/sched.h>
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#include <sys/stack.h>
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#include <sys/sysctl.h>
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#include <sys/systm.h>
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#ifdef DDB
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#include <ddb/ddb.h>
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#endif
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#include <machine/stdarg.h>
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#if !defined(DDB) && !defined(STACK)
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#error "DDB or STACK options are required for WITNESS"
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#endif
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/* Note that these traces do not work with KTR_ALQ. */
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#if 0
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#define KTR_WITNESS KTR_SUBSYS
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#else
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#define KTR_WITNESS 0
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#endif
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#define LI_RECURSEMASK 0x0000ffff /* Recursion depth of lock instance. */
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#define LI_EXCLUSIVE 0x00010000 /* Exclusive lock instance. */
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#define LI_NORELEASE 0x00020000 /* Lock not allowed to be released. */
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/* Define this to check for blessed mutexes */
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#undef BLESSING
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#define WITNESS_COUNT 1024
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#define WITNESS_CHILDCOUNT (WITNESS_COUNT * 4)
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#define WITNESS_HASH_SIZE 251 /* Prime, gives load factor < 2 */
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#define WITNESS_PENDLIST 768
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/* Allocate 256 KB of stack data space */
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#define WITNESS_LO_DATA_COUNT 2048
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/* Prime, gives load factor of ~2 at full load */
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#define WITNESS_LO_HASH_SIZE 1021
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/*
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* XXX: This is somewhat bogus, as we assume here that at most 2048 threads
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* will hold LOCK_NCHILDREN locks. We handle failure ok, and we should
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* probably be safe for the most part, but it's still a SWAG.
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*/
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#define LOCK_NCHILDREN 5
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#define LOCK_CHILDCOUNT 2048
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#define MAX_W_NAME 64
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#define BADSTACK_SBUF_SIZE (256 * WITNESS_COUNT)
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#define CYCLEGRAPH_SBUF_SIZE 8192
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#define FULLGRAPH_SBUF_SIZE 32768
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/*
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* These flags go in the witness relationship matrix and describe the
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* relationship between any two struct witness objects.
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*/
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#define WITNESS_UNRELATED 0x00 /* No lock order relation. */
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#define WITNESS_PARENT 0x01 /* Parent, aka direct ancestor. */
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#define WITNESS_ANCESTOR 0x02 /* Direct or indirect ancestor. */
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#define WITNESS_CHILD 0x04 /* Child, aka direct descendant. */
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#define WITNESS_DESCENDANT 0x08 /* Direct or indirect descendant. */
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#define WITNESS_ANCESTOR_MASK (WITNESS_PARENT | WITNESS_ANCESTOR)
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#define WITNESS_DESCENDANT_MASK (WITNESS_CHILD | WITNESS_DESCENDANT)
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#define WITNESS_RELATED_MASK \
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(WITNESS_ANCESTOR_MASK | WITNESS_DESCENDANT_MASK)
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#define WITNESS_REVERSAL 0x10 /* A lock order reversal has been
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* observed. */
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#define WITNESS_RESERVED1 0x20 /* Unused flag, reserved. */
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#define WITNESS_RESERVED2 0x40 /* Unused flag, reserved. */
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#define WITNESS_LOCK_ORDER_KNOWN 0x80 /* This lock order is known. */
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/* Descendant to ancestor flags */
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#define WITNESS_DTOA(x) (((x) & WITNESS_RELATED_MASK) >> 2)
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/* Ancestor to descendant flags */
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#define WITNESS_ATOD(x) (((x) & WITNESS_RELATED_MASK) << 2)
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#define WITNESS_INDEX_ASSERT(i) \
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MPASS((i) > 0 && (i) <= w_max_used_index && (i) < WITNESS_COUNT)
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MALLOC_DEFINE(M_WITNESS, "Witness", "Witness");
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/*
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* Lock instances. A lock instance is the data associated with a lock while
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* it is held by witness. For example, a lock instance will hold the
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* recursion count of a lock. Lock instances are held in lists. Spin locks
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* are held in a per-cpu list while sleep locks are held in per-thread list.
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*/
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struct lock_instance {
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struct lock_object *li_lock;
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const char *li_file;
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int li_line;
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u_int li_flags;
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};
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/*
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* A simple list type used to build the list of locks held by a thread
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* or CPU. We can't simply embed the list in struct lock_object since a
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* lock may be held by more than one thread if it is a shared lock. Locks
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* are added to the head of the list, so we fill up each list entry from
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* "the back" logically. To ease some of the arithmetic, we actually fill
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* in each list entry the normal way (children[0] then children[1], etc.) but
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* when we traverse the list we read children[count-1] as the first entry
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* down to children[0] as the final entry.
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*/
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struct lock_list_entry {
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struct lock_list_entry *ll_next;
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struct lock_instance ll_children[LOCK_NCHILDREN];
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u_int ll_count;
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};
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/*
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* The main witness structure. One of these per named lock type in the system
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* (for example, "vnode interlock").
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*/
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struct witness {
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char w_name[MAX_W_NAME];
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uint32_t w_index; /* Index in the relationship matrix */
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struct lock_class *w_class;
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STAILQ_ENTRY(witness) w_list; /* List of all witnesses. */
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STAILQ_ENTRY(witness) w_typelist; /* Witnesses of a type. */
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struct witness *w_hash_next; /* Linked list in hash buckets. */
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const char *w_file; /* File where last acquired */
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uint32_t w_line; /* Line where last acquired */
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uint32_t w_refcount;
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uint16_t w_num_ancestors; /* direct/indirect
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* ancestor count */
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uint16_t w_num_descendants; /* direct/indirect
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* descendant count */
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int16_t w_ddb_level;
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unsigned w_displayed:1;
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unsigned w_reversed:1;
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};
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STAILQ_HEAD(witness_list, witness);
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/*
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* The witness hash table. Keys are witness names (const char *), elements are
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* witness objects (struct witness *).
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*/
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struct witness_hash {
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struct witness *wh_array[WITNESS_HASH_SIZE];
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uint32_t wh_size;
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uint32_t wh_count;
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};
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/*
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* Key type for the lock order data hash table.
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*/
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struct witness_lock_order_key {
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uint16_t from;
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uint16_t to;
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};
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struct witness_lock_order_data {
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struct stack wlod_stack;
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struct witness_lock_order_key wlod_key;
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struct witness_lock_order_data *wlod_next;
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};
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/*
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* The witness lock order data hash table. Keys are witness index tuples
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* (struct witness_lock_order_key), elements are lock order data objects
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* (struct witness_lock_order_data).
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*/
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struct witness_lock_order_hash {
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struct witness_lock_order_data *wloh_array[WITNESS_LO_HASH_SIZE];
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u_int wloh_size;
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u_int wloh_count;
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};
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#ifdef BLESSING
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struct witness_blessed {
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const char *b_lock1;
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const char *b_lock2;
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};
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#endif
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struct witness_pendhelp {
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const char *wh_type;
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struct lock_object *wh_lock;
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};
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struct witness_order_list_entry {
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const char *w_name;
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struct lock_class *w_class;
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};
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/*
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* Returns 0 if one of the locks is a spin lock and the other is not.
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* Returns 1 otherwise.
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*/
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static __inline int
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witness_lock_type_equal(struct witness *w1, struct witness *w2)
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{
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return ((w1->w_class->lc_flags & (LC_SLEEPLOCK | LC_SPINLOCK)) ==
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(w2->w_class->lc_flags & (LC_SLEEPLOCK | LC_SPINLOCK)));
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}
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static __inline int
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witness_lock_order_key_empty(const struct witness_lock_order_key *key)
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{
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return (key->from == 0 && key->to == 0);
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}
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static __inline int
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witness_lock_order_key_equal(const struct witness_lock_order_key *a,
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const struct witness_lock_order_key *b)
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{
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return (a->from == b->from && a->to == b->to);
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}
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static int _isitmyx(struct witness *w1, struct witness *w2, int rmask,
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const char *fname);
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#ifdef KDB
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static void _witness_debugger(int cond, const char *msg);
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#endif
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static void adopt(struct witness *parent, struct witness *child);
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#ifdef BLESSING
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static int blessed(struct witness *, struct witness *);
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#endif
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static void depart(struct witness *w);
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static struct witness *enroll(const char *description,
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struct lock_class *lock_class);
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static struct lock_instance *find_instance(struct lock_list_entry *list,
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struct lock_object *lock);
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static int isitmychild(struct witness *parent, struct witness *child);
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static int isitmydescendant(struct witness *parent, struct witness *child);
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static void itismychild(struct witness *parent, struct witness *child);
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static int sysctl_debug_witness_badstacks(SYSCTL_HANDLER_ARGS);
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static int sysctl_debug_witness_watch(SYSCTL_HANDLER_ARGS);
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static int sysctl_debug_witness_fullgraph(SYSCTL_HANDLER_ARGS);
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static void witness_add_fullgraph(struct sbuf *sb, struct witness *parent);
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#ifdef DDB
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static void witness_ddb_compute_levels(void);
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static void witness_ddb_display(int(*)(const char *fmt, ...));
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static void witness_ddb_display_descendants(int(*)(const char *fmt, ...),
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struct witness *, int indent);
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static void witness_ddb_display_list(int(*prnt)(const char *fmt, ...),
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struct witness_list *list);
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static void witness_ddb_level_descendants(struct witness *parent, int l);
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static void witness_ddb_list(struct thread *td);
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#endif
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static void witness_free(struct witness *m);
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static struct witness *witness_get(void);
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static uint32_t witness_hash_djb2(const uint8_t *key, uint32_t size);
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static struct witness *witness_hash_get(const char *key);
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static void witness_hash_put(struct witness *w);
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static void witness_init_hash_tables(void);
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static void witness_increment_graph_generation(void);
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static void witness_lock_list_free(struct lock_list_entry *lle);
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static struct lock_list_entry *witness_lock_list_get(void);
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static int witness_lock_order_add(struct witness *parent,
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struct witness *child);
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static int witness_lock_order_check(struct witness *parent,
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struct witness *child);
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static struct witness_lock_order_data *witness_lock_order_get(
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struct witness *parent,
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struct witness *child);
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static void witness_list_lock(struct lock_instance *instance,
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int (*prnt)(const char *fmt, ...));
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static void witness_setflag(struct lock_object *lock, int flag, int set);
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#ifdef KDB
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#define witness_debugger(c) _witness_debugger(c, __func__)
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#else
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#define witness_debugger(c)
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#endif
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SYSCTL_NODE(_debug, OID_AUTO, witness, CTLFLAG_RW, NULL, "Witness Locking");
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/*
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* If set to 0, lock order checking is disabled. If set to -1,
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* witness is completely disabled. Otherwise witness performs full
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* lock order checking for all locks. At runtime, lock order checking
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* may be toggled. However, witness cannot be reenabled once it is
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* completely disabled.
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*/
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static int witness_watch = 1;
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TUNABLE_INT("debug.witness.watch", &witness_watch);
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SYSCTL_PROC(_debug_witness, OID_AUTO, watch, CTLFLAG_RW | CTLTYPE_INT, NULL, 0,
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sysctl_debug_witness_watch, "I", "witness is watching lock operations");
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#ifdef KDB
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/*
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* When KDB is enabled and witness_kdb is 1, it will cause the system
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* to drop into kdebug() when:
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* - a lock hierarchy violation occurs
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* - locks are held when going to sleep.
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*/
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#ifdef WITNESS_KDB
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int witness_kdb = 1;
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#else
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int witness_kdb = 0;
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#endif
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TUNABLE_INT("debug.witness.kdb", &witness_kdb);
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SYSCTL_INT(_debug_witness, OID_AUTO, kdb, CTLFLAG_RW, &witness_kdb, 0, "");
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/*
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* When KDB is enabled and witness_trace is 1, it will cause the system
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* to print a stack trace:
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* - a lock hierarchy violation occurs
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* - locks are held when going to sleep.
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*/
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int witness_trace = 1;
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TUNABLE_INT("debug.witness.trace", &witness_trace);
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SYSCTL_INT(_debug_witness, OID_AUTO, trace, CTLFLAG_RW, &witness_trace, 0, "");
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#endif /* KDB */
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#ifdef WITNESS_SKIPSPIN
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int witness_skipspin = 1;
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#else
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int witness_skipspin = 0;
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#endif
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TUNABLE_INT("debug.witness.skipspin", &witness_skipspin);
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SYSCTL_INT(_debug_witness, OID_AUTO, skipspin, CTLFLAG_RDTUN, &witness_skipspin,
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0, "");
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/*
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* Call this to print out the relations between locks.
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*/
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SYSCTL_PROC(_debug_witness, OID_AUTO, fullgraph, CTLTYPE_STRING | CTLFLAG_RD,
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NULL, 0, sysctl_debug_witness_fullgraph, "A", "Show locks relation graphs");
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/*
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* Call this to print out the witness faulty stacks.
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*/
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SYSCTL_PROC(_debug_witness, OID_AUTO, badstacks, CTLTYPE_STRING | CTLFLAG_RD,
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NULL, 0, sysctl_debug_witness_badstacks, "A", "Show bad witness stacks");
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static struct mtx w_mtx;
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/* w_list */
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static struct witness_list w_free = STAILQ_HEAD_INITIALIZER(w_free);
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static struct witness_list w_all = STAILQ_HEAD_INITIALIZER(w_all);
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/* w_typelist */
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static struct witness_list w_spin = STAILQ_HEAD_INITIALIZER(w_spin);
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static struct witness_list w_sleep = STAILQ_HEAD_INITIALIZER(w_sleep);
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/* lock list */
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static struct lock_list_entry *w_lock_list_free = NULL;
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static struct witness_pendhelp pending_locks[WITNESS_PENDLIST];
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static u_int pending_cnt;
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static int w_free_cnt, w_spin_cnt, w_sleep_cnt;
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SYSCTL_INT(_debug_witness, OID_AUTO, free_cnt, CTLFLAG_RD, &w_free_cnt, 0, "");
|
|
SYSCTL_INT(_debug_witness, OID_AUTO, spin_cnt, CTLFLAG_RD, &w_spin_cnt, 0, "");
|
|
SYSCTL_INT(_debug_witness, OID_AUTO, sleep_cnt, CTLFLAG_RD, &w_sleep_cnt, 0,
|
|
"");
|
|
|
|
static struct witness *w_data;
|
|
static uint8_t w_rmatrix[WITNESS_COUNT+1][WITNESS_COUNT+1];
|
|
static struct lock_list_entry w_locklistdata[LOCK_CHILDCOUNT];
|
|
static struct witness_hash w_hash; /* The witness hash table. */
|
|
|
|
/* The lock order data hash */
|
|
static struct witness_lock_order_data w_lodata[WITNESS_LO_DATA_COUNT];
|
|
static struct witness_lock_order_data *w_lofree = NULL;
|
|
static struct witness_lock_order_hash w_lohash;
|
|
static int w_max_used_index = 0;
|
|
static unsigned int w_generation = 0;
|
|
static const char w_notrunning[] = "Witness not running\n";
|
|
static const char w_stillcold[] = "Witness is still cold\n";
|
|
|
|
|
|
static struct witness_order_list_entry order_lists[] = {
|
|
/*
|
|
* sx locks
|
|
*/
|
|
{ "proctree", &lock_class_sx },
|
|
{ "allproc", &lock_class_sx },
|
|
{ "allprison", &lock_class_sx },
|
|
{ NULL, NULL },
|
|
/*
|
|
* Various mutexes
|
|
*/
|
|
{ "Giant", &lock_class_mtx_sleep },
|
|
{ "pipe mutex", &lock_class_mtx_sleep },
|
|
{ "sigio lock", &lock_class_mtx_sleep },
|
|
{ "process group", &lock_class_mtx_sleep },
|
|
{ "process lock", &lock_class_mtx_sleep },
|
|
{ "session", &lock_class_mtx_sleep },
|
|
{ "uidinfo hash", &lock_class_rw },
|
|
#ifdef HWPMC_HOOKS
|
|
{ "pmc-sleep", &lock_class_mtx_sleep },
|
|
#endif
|
|
{ "time lock", &lock_class_mtx_sleep },
|
|
{ NULL, NULL },
|
|
/*
|
|
* Sockets
|
|
*/
|
|
{ "accept", &lock_class_mtx_sleep },
|
|
{ "so_snd", &lock_class_mtx_sleep },
|
|
{ "so_rcv", &lock_class_mtx_sleep },
|
|
{ "sellck", &lock_class_mtx_sleep },
|
|
{ NULL, NULL },
|
|
/*
|
|
* Routing
|
|
*/
|
|
{ "so_rcv", &lock_class_mtx_sleep },
|
|
{ "radix node head", &lock_class_rw },
|
|
{ "rtentry", &lock_class_mtx_sleep },
|
|
{ "ifaddr", &lock_class_mtx_sleep },
|
|
{ NULL, NULL },
|
|
/*
|
|
* IPv4 multicast:
|
|
* protocol locks before interface locks, after UDP locks.
|
|
*/
|
|
{ "udpinp", &lock_class_rw },
|
|
{ "in_multi_mtx", &lock_class_mtx_sleep },
|
|
{ "igmp_mtx", &lock_class_mtx_sleep },
|
|
{ "if_addr_mtx", &lock_class_mtx_sleep },
|
|
{ NULL, NULL },
|
|
/*
|
|
* IPv6 multicast:
|
|
* protocol locks before interface locks, after UDP locks.
|
|
*/
|
|
{ "udpinp", &lock_class_rw },
|
|
{ "in6_multi_mtx", &lock_class_mtx_sleep },
|
|
{ "mld_mtx", &lock_class_mtx_sleep },
|
|
{ "if_addr_mtx", &lock_class_mtx_sleep },
|
|
{ NULL, NULL },
|
|
/*
|
|
* UNIX Domain Sockets
|
|
*/
|
|
{ "unp_global_rwlock", &lock_class_rw },
|
|
{ "unp_list_lock", &lock_class_mtx_sleep },
|
|
{ "unp", &lock_class_mtx_sleep },
|
|
{ "so_snd", &lock_class_mtx_sleep },
|
|
{ NULL, NULL },
|
|
/*
|
|
* UDP/IP
|
|
*/
|
|
{ "udp", &lock_class_rw },
|
|
{ "udpinp", &lock_class_rw },
|
|
{ "so_snd", &lock_class_mtx_sleep },
|
|
{ NULL, NULL },
|
|
/*
|
|
* TCP/IP
|
|
*/
|
|
{ "tcp", &lock_class_rw },
|
|
{ "tcpinp", &lock_class_rw },
|
|
{ "so_snd", &lock_class_mtx_sleep },
|
|
{ NULL, NULL },
|
|
/*
|
|
* netatalk
|
|
*/
|
|
{ "ddp_list_mtx", &lock_class_mtx_sleep },
|
|
{ "ddp_mtx", &lock_class_mtx_sleep },
|
|
{ NULL, NULL },
|
|
/*
|
|
* BPF
|
|
*/
|
|
{ "bpf global lock", &lock_class_mtx_sleep },
|
|
{ "bpf interface lock", &lock_class_mtx_sleep },
|
|
{ "bpf cdev lock", &lock_class_mtx_sleep },
|
|
{ NULL, NULL },
|
|
/*
|
|
* NFS server
|
|
*/
|
|
{ "nfsd_mtx", &lock_class_mtx_sleep },
|
|
{ "so_snd", &lock_class_mtx_sleep },
|
|
{ NULL, NULL },
|
|
|
|
/*
|
|
* IEEE 802.11
|
|
*/
|
|
{ "802.11 com lock", &lock_class_mtx_sleep},
|
|
{ NULL, NULL },
|
|
/*
|
|
* Network drivers
|
|
*/
|
|
{ "network driver", &lock_class_mtx_sleep},
|
|
{ NULL, NULL },
|
|
|
|
/*
|
|
* Netgraph
|
|
*/
|
|
{ "ng_node", &lock_class_mtx_sleep },
|
|
{ "ng_worklist", &lock_class_mtx_sleep },
|
|
{ NULL, NULL },
|
|
/*
|
|
* CDEV
|
|
*/
|
|
{ "system map", &lock_class_mtx_sleep },
|
|
{ "vm page queue mutex", &lock_class_mtx_sleep },
|
|
{ "vnode interlock", &lock_class_mtx_sleep },
|
|
{ "cdev", &lock_class_mtx_sleep },
|
|
{ NULL, NULL },
|
|
/*
|
|
* VM
|
|
*
|
|
*/
|
|
{ "vm object", &lock_class_mtx_sleep },
|
|
{ "page lock", &lock_class_mtx_sleep },
|
|
{ "vm page queue mutex", &lock_class_mtx_sleep },
|
|
{ "pmap", &lock_class_mtx_sleep },
|
|
{ NULL, NULL },
|
|
/*
|
|
* kqueue/VFS interaction
|
|
*/
|
|
{ "kqueue", &lock_class_mtx_sleep },
|
|
{ "struct mount mtx", &lock_class_mtx_sleep },
|
|
{ "vnode interlock", &lock_class_mtx_sleep },
|
|
{ NULL, NULL },
|
|
/*
|
|
* ZFS locking
|
|
*/
|
|
{ "dn->dn_mtx", &lock_class_sx },
|
|
{ "dr->dt.di.dr_mtx", &lock_class_sx },
|
|
{ "db->db_mtx", &lock_class_sx },
|
|
{ NULL, NULL },
|
|
/*
|
|
* spin locks
|
|
*/
|
|
#ifdef SMP
|
|
{ "ap boot", &lock_class_mtx_spin },
|
|
#endif
|
|
{ "rm.mutex_mtx", &lock_class_mtx_spin },
|
|
{ "sio", &lock_class_mtx_spin },
|
|
{ "scrlock", &lock_class_mtx_spin },
|
|
#ifdef __i386__
|
|
{ "cy", &lock_class_mtx_spin },
|
|
#endif
|
|
#ifdef __sparc64__
|
|
{ "pcib_mtx", &lock_class_mtx_spin },
|
|
{ "rtc_mtx", &lock_class_mtx_spin },
|
|
#endif
|
|
{ "scc_hwmtx", &lock_class_mtx_spin },
|
|
{ "uart_hwmtx", &lock_class_mtx_spin },
|
|
{ "fast_taskqueue", &lock_class_mtx_spin },
|
|
{ "intr table", &lock_class_mtx_spin },
|
|
#ifdef HWPMC_HOOKS
|
|
{ "pmc-per-proc", &lock_class_mtx_spin },
|
|
#endif
|
|
{ "process slock", &lock_class_mtx_spin },
|
|
{ "sleepq chain", &lock_class_mtx_spin },
|
|
{ "umtx lock", &lock_class_mtx_spin },
|
|
{ "rm_spinlock", &lock_class_mtx_spin },
|
|
{ "turnstile chain", &lock_class_mtx_spin },
|
|
{ "turnstile lock", &lock_class_mtx_spin },
|
|
{ "sched lock", &lock_class_mtx_spin },
|
|
{ "td_contested", &lock_class_mtx_spin },
|
|
{ "callout", &lock_class_mtx_spin },
|
|
{ "entropy harvest mutex", &lock_class_mtx_spin },
|
|
{ "syscons video lock", &lock_class_mtx_spin },
|
|
#ifdef SMP
|
|
{ "smp rendezvous", &lock_class_mtx_spin },
|
|
#endif
|
|
#ifdef __powerpc__
|
|
{ "tlb0", &lock_class_mtx_spin },
|
|
#endif
|
|
/*
|
|
* leaf locks
|
|
*/
|
|
{ "intrcnt", &lock_class_mtx_spin },
|
|
{ "icu", &lock_class_mtx_spin },
|
|
#if defined(SMP) && defined(__sparc64__)
|
|
{ "ipi", &lock_class_mtx_spin },
|
|
#endif
|
|
#ifdef __i386__
|
|
{ "allpmaps", &lock_class_mtx_spin },
|
|
{ "descriptor tables", &lock_class_mtx_spin },
|
|
#endif
|
|
{ "clk", &lock_class_mtx_spin },
|
|
{ "cpuset", &lock_class_mtx_spin },
|
|
{ "mprof lock", &lock_class_mtx_spin },
|
|
{ "zombie lock", &lock_class_mtx_spin },
|
|
{ "ALD Queue", &lock_class_mtx_spin },
|
|
#ifdef __ia64__
|
|
{ "MCA spin lock", &lock_class_mtx_spin },
|
|
#endif
|
|
#if defined(__i386__) || defined(__amd64__)
|
|
{ "pcicfg", &lock_class_mtx_spin },
|
|
{ "NDIS thread lock", &lock_class_mtx_spin },
|
|
#endif
|
|
{ "tw_osl_io_lock", &lock_class_mtx_spin },
|
|
{ "tw_osl_q_lock", &lock_class_mtx_spin },
|
|
{ "tw_cl_io_lock", &lock_class_mtx_spin },
|
|
{ "tw_cl_intr_lock", &lock_class_mtx_spin },
|
|
{ "tw_cl_gen_lock", &lock_class_mtx_spin },
|
|
#ifdef HWPMC_HOOKS
|
|
{ "pmc-leaf", &lock_class_mtx_spin },
|
|
#endif
|
|
{ "blocked lock", &lock_class_mtx_spin },
|
|
{ NULL, NULL },
|
|
{ NULL, NULL }
|
|
};
|
|
|
|
#ifdef BLESSING
|
|
/*
|
|
* Pairs of locks which have been blessed
|
|
* Don't complain about order problems with blessed locks
|
|
*/
|
|
static struct witness_blessed blessed_list[] = {
|
|
};
|
|
static int blessed_count =
|
|
sizeof(blessed_list) / sizeof(struct witness_blessed);
|
|
#endif
|
|
|
|
/*
|
|
* This global is set to 0 once it becomes safe to use the witness code.
|
|
*/
|
|
static int witness_cold = 1;
|
|
|
|
/*
|
|
* This global is set to 1 once the static lock orders have been enrolled
|
|
* so that a warning can be issued for any spin locks enrolled later.
|
|
*/
|
|
static int witness_spin_warn = 0;
|
|
|
|
/*
|
|
* The WITNESS-enabled diagnostic code. Note that the witness code does
|
|
* assume that the early boot is single-threaded at least until after this
|
|
* routine is completed.
|
|
*/
|
|
static void
|
|
witness_initialize(void *dummy __unused)
|
|
{
|
|
struct lock_object *lock;
|
|
struct witness_order_list_entry *order;
|
|
struct witness *w, *w1;
|
|
int i;
|
|
|
|
w_data = malloc(sizeof (struct witness) * WITNESS_COUNT, M_WITNESS,
|
|
M_NOWAIT | M_ZERO);
|
|
|
|
/*
|
|
* We have to release Giant before initializing its witness
|
|
* structure so that WITNESS doesn't get confused.
|
|
*/
|
|
mtx_unlock(&Giant);
|
|
mtx_assert(&Giant, MA_NOTOWNED);
|
|
|
|
CTR1(KTR_WITNESS, "%s: initializing witness", __func__);
|
|
mtx_init(&w_mtx, "witness lock", NULL, MTX_SPIN | MTX_QUIET |
|
|
MTX_NOWITNESS | MTX_NOPROFILE);
|
|
for (i = WITNESS_COUNT - 1; i >= 0; i--) {
|
|
w = &w_data[i];
|
|
memset(w, 0, sizeof(*w));
|
|
w_data[i].w_index = i; /* Witness index never changes. */
|
|
witness_free(w);
|
|
}
|
|
KASSERT(STAILQ_FIRST(&w_free)->w_index == 0,
|
|
("%s: Invalid list of free witness objects", __func__));
|
|
|
|
/* Witness with index 0 is not used to aid in debugging. */
|
|
STAILQ_REMOVE_HEAD(&w_free, w_list);
|
|
w_free_cnt--;
|
|
|
|
memset(w_rmatrix, 0,
|
|
(sizeof(**w_rmatrix) * (WITNESS_COUNT+1) * (WITNESS_COUNT+1)));
|
|
|
|
for (i = 0; i < LOCK_CHILDCOUNT; i++)
|
|
witness_lock_list_free(&w_locklistdata[i]);
|
|
witness_init_hash_tables();
|
|
|
|
/* First add in all the specified order lists. */
|
|
for (order = order_lists; order->w_name != NULL; order++) {
|
|
w = enroll(order->w_name, order->w_class);
|
|
if (w == NULL)
|
|
continue;
|
|
w->w_file = "order list";
|
|
for (order++; order->w_name != NULL; order++) {
|
|
w1 = enroll(order->w_name, order->w_class);
|
|
if (w1 == NULL)
|
|
continue;
|
|
w1->w_file = "order list";
|
|
itismychild(w, w1);
|
|
w = w1;
|
|
}
|
|
}
|
|
witness_spin_warn = 1;
|
|
|
|
/* Iterate through all locks and add them to witness. */
|
|
for (i = 0; pending_locks[i].wh_lock != NULL; i++) {
|
|
lock = pending_locks[i].wh_lock;
|
|
KASSERT(lock->lo_flags & LO_WITNESS,
|
|
("%s: lock %s is on pending list but not LO_WITNESS",
|
|
__func__, lock->lo_name));
|
|
lock->lo_witness = enroll(pending_locks[i].wh_type,
|
|
LOCK_CLASS(lock));
|
|
}
|
|
|
|
/* Mark the witness code as being ready for use. */
|
|
witness_cold = 0;
|
|
|
|
mtx_lock(&Giant);
|
|
}
|
|
SYSINIT(witness_init, SI_SUB_WITNESS, SI_ORDER_FIRST, witness_initialize,
|
|
NULL);
|
|
|
|
void
|
|
witness_init(struct lock_object *lock, const char *type)
|
|
{
|
|
struct lock_class *class;
|
|
|
|
/* Various sanity checks. */
|
|
class = LOCK_CLASS(lock);
|
|
if ((lock->lo_flags & LO_RECURSABLE) != 0 &&
|
|
(class->lc_flags & LC_RECURSABLE) == 0)
|
|
panic("%s: lock (%s) %s can not be recursable", __func__,
|
|
class->lc_name, lock->lo_name);
|
|
if ((lock->lo_flags & LO_SLEEPABLE) != 0 &&
|
|
(class->lc_flags & LC_SLEEPABLE) == 0)
|
|
panic("%s: lock (%s) %s can not be sleepable", __func__,
|
|
class->lc_name, lock->lo_name);
|
|
if ((lock->lo_flags & LO_UPGRADABLE) != 0 &&
|
|
(class->lc_flags & LC_UPGRADABLE) == 0)
|
|
panic("%s: lock (%s) %s can not be upgradable", __func__,
|
|
class->lc_name, lock->lo_name);
|
|
|
|
/*
|
|
* If we shouldn't watch this lock, then just clear lo_witness.
|
|
* Otherwise, if witness_cold is set, then it is too early to
|
|
* enroll this lock, so defer it to witness_initialize() by adding
|
|
* it to the pending_locks list. If it is not too early, then enroll
|
|
* the lock now.
|
|
*/
|
|
if (witness_watch < 1 || panicstr != NULL ||
|
|
(lock->lo_flags & LO_WITNESS) == 0)
|
|
lock->lo_witness = NULL;
|
|
else if (witness_cold) {
|
|
pending_locks[pending_cnt].wh_lock = lock;
|
|
pending_locks[pending_cnt++].wh_type = type;
|
|
if (pending_cnt > WITNESS_PENDLIST)
|
|
panic("%s: pending locks list is too small, bump it\n",
|
|
__func__);
|
|
} else
|
|
lock->lo_witness = enroll(type, class);
|
|
}
|
|
|
|
void
|
|
witness_destroy(struct lock_object *lock)
|
|
{
|
|
struct lock_class *class;
|
|
struct witness *w;
|
|
|
|
class = LOCK_CLASS(lock);
|
|
|
|
if (witness_cold)
|
|
panic("lock (%s) %s destroyed while witness_cold",
|
|
class->lc_name, lock->lo_name);
|
|
|
|
/* XXX: need to verify that no one holds the lock */
|
|
if ((lock->lo_flags & LO_WITNESS) == 0 || lock->lo_witness == NULL)
|
|
return;
|
|
w = lock->lo_witness;
|
|
|
|
mtx_lock_spin(&w_mtx);
|
|
MPASS(w->w_refcount > 0);
|
|
w->w_refcount--;
|
|
|
|
if (w->w_refcount == 0)
|
|
depart(w);
|
|
mtx_unlock_spin(&w_mtx);
|
|
}
|
|
|
|
#ifdef DDB
|
|
static void
|
|
witness_ddb_compute_levels(void)
|
|
{
|
|
struct witness *w;
|
|
|
|
/*
|
|
* First clear all levels.
|
|
*/
|
|
STAILQ_FOREACH(w, &w_all, w_list)
|
|
w->w_ddb_level = -1;
|
|
|
|
/*
|
|
* Look for locks with no parents and level all their descendants.
|
|
*/
|
|
STAILQ_FOREACH(w, &w_all, w_list) {
|
|
|
|
/* If the witness has ancestors (is not a root), skip it. */
|
|
if (w->w_num_ancestors > 0)
|
|
continue;
|
|
witness_ddb_level_descendants(w, 0);
|
|
}
|
|
}
|
|
|
|
static void
|
|
witness_ddb_level_descendants(struct witness *w, int l)
|
|
{
|
|
int i;
|
|
|
|
if (w->w_ddb_level >= l)
|
|
return;
|
|
|
|
w->w_ddb_level = l;
|
|
l++;
|
|
|
|
for (i = 1; i <= w_max_used_index; i++) {
|
|
if (w_rmatrix[w->w_index][i] & WITNESS_PARENT)
|
|
witness_ddb_level_descendants(&w_data[i], l);
|
|
}
|
|
}
|
|
|
|
static void
|
|
witness_ddb_display_descendants(int(*prnt)(const char *fmt, ...),
|
|
struct witness *w, int indent)
|
|
{
|
|
int i;
|
|
|
|
for (i = 0; i < indent; i++)
|
|
prnt(" ");
|
|
prnt("%s (type: %s, depth: %d, active refs: %d)",
|
|
w->w_name, w->w_class->lc_name,
|
|
w->w_ddb_level, w->w_refcount);
|
|
if (w->w_displayed) {
|
|
prnt(" -- (already displayed)\n");
|
|
return;
|
|
}
|
|
w->w_displayed = 1;
|
|
if (w->w_file != NULL && w->w_line != 0)
|
|
prnt(" -- last acquired @ %s:%d\n", w->w_file,
|
|
w->w_line);
|
|
else
|
|
prnt(" -- never acquired\n");
|
|
indent++;
|
|
WITNESS_INDEX_ASSERT(w->w_index);
|
|
for (i = 1; i <= w_max_used_index; i++) {
|
|
if (w_rmatrix[w->w_index][i] & WITNESS_PARENT)
|
|
witness_ddb_display_descendants(prnt, &w_data[i],
|
|
indent);
|
|
}
|
|
}
|
|
|
|
static void
|
|
witness_ddb_display_list(int(*prnt)(const char *fmt, ...),
|
|
struct witness_list *list)
|
|
{
|
|
struct witness *w;
|
|
|
|
STAILQ_FOREACH(w, list, w_typelist) {
|
|
if (w->w_file == NULL || w->w_ddb_level > 0)
|
|
continue;
|
|
|
|
/* This lock has no anscestors - display its descendants. */
|
|
witness_ddb_display_descendants(prnt, w, 0);
|
|
}
|
|
}
|
|
|
|
static void
|
|
witness_ddb_display(int(*prnt)(const char *fmt, ...))
|
|
{
|
|
struct witness *w;
|
|
|
|
KASSERT(witness_cold == 0, ("%s: witness_cold", __func__));
|
|
witness_ddb_compute_levels();
|
|
|
|
/* Clear all the displayed flags. */
|
|
STAILQ_FOREACH(w, &w_all, w_list)
|
|
w->w_displayed = 0;
|
|
|
|
/*
|
|
* First, handle sleep locks which have been acquired at least
|
|
* once.
|
|
*/
|
|
prnt("Sleep locks:\n");
|
|
witness_ddb_display_list(prnt, &w_sleep);
|
|
|
|
/*
|
|
* Now do spin locks which have been acquired at least once.
|
|
*/
|
|
prnt("\nSpin locks:\n");
|
|
witness_ddb_display_list(prnt, &w_spin);
|
|
|
|
/*
|
|
* Finally, any locks which have not been acquired yet.
|
|
*/
|
|
prnt("\nLocks which were never acquired:\n");
|
|
STAILQ_FOREACH(w, &w_all, w_list) {
|
|
if (w->w_file != NULL || w->w_refcount == 0)
|
|
continue;
|
|
prnt("%s (type: %s, depth: %d)\n", w->w_name,
|
|
w->w_class->lc_name, w->w_ddb_level);
|
|
}
|
|
}
|
|
#endif /* DDB */
|
|
|
|
/* Trim useless garbage from filenames. */
|
|
static const char *
|
|
fixup_filename(const char *file)
|
|
{
|
|
|
|
if (file == NULL)
|
|
return (NULL);
|
|
while (strncmp(file, "../", 3) == 0)
|
|
file += 3;
|
|
return (file);
|
|
}
|
|
|
|
int
|
|
witness_defineorder(struct lock_object *lock1, struct lock_object *lock2)
|
|
{
|
|
|
|
if (witness_watch == -1 || panicstr != NULL)
|
|
return (0);
|
|
|
|
/* Require locks that witness knows about. */
|
|
if (lock1 == NULL || lock1->lo_witness == NULL || lock2 == NULL ||
|
|
lock2->lo_witness == NULL)
|
|
return (EINVAL);
|
|
|
|
mtx_assert(&w_mtx, MA_NOTOWNED);
|
|
mtx_lock_spin(&w_mtx);
|
|
|
|
/*
|
|
* If we already have either an explicit or implied lock order that
|
|
* is the other way around, then return an error.
|
|
*/
|
|
if (witness_watch &&
|
|
isitmydescendant(lock2->lo_witness, lock1->lo_witness)) {
|
|
mtx_unlock_spin(&w_mtx);
|
|
return (EDOOFUS);
|
|
}
|
|
|
|
/* Try to add the new order. */
|
|
CTR3(KTR_WITNESS, "%s: adding %s as a child of %s", __func__,
|
|
lock2->lo_witness->w_name, lock1->lo_witness->w_name);
|
|
itismychild(lock1->lo_witness, lock2->lo_witness);
|
|
mtx_unlock_spin(&w_mtx);
|
|
return (0);
|
|
}
|
|
|
|
void
|
|
witness_checkorder(struct lock_object *lock, int flags, const char *file,
|
|
int line, struct lock_object *interlock)
|
|
{
|
|
struct lock_list_entry *lock_list, *lle;
|
|
struct lock_instance *lock1, *lock2, *plock;
|
|
struct lock_class *class;
|
|
struct witness *w, *w1;
|
|
struct thread *td;
|
|
int i, j;
|
|
|
|
if (witness_cold || witness_watch < 1 || lock->lo_witness == NULL ||
|
|
panicstr != NULL)
|
|
return;
|
|
|
|
w = lock->lo_witness;
|
|
class = LOCK_CLASS(lock);
|
|
td = curthread;
|
|
file = fixup_filename(file);
|
|
|
|
if (class->lc_flags & LC_SLEEPLOCK) {
|
|
|
|
/*
|
|
* Since spin locks include a critical section, this check
|
|
* implicitly enforces a lock order of all sleep locks before
|
|
* all spin locks.
|
|
*/
|
|
if (td->td_critnest != 0 && !kdb_active)
|
|
panic("blockable sleep lock (%s) %s @ %s:%d",
|
|
class->lc_name, lock->lo_name, file, line);
|
|
|
|
/*
|
|
* If this is the first lock acquired then just return as
|
|
* no order checking is needed.
|
|
*/
|
|
lock_list = td->td_sleeplocks;
|
|
if (lock_list == NULL || lock_list->ll_count == 0)
|
|
return;
|
|
} else {
|
|
|
|
/*
|
|
* If this is the first lock, just return as no order
|
|
* checking is needed. Avoid problems with thread
|
|
* migration pinning the thread while checking if
|
|
* spinlocks are held. If at least one spinlock is held
|
|
* the thread is in a safe path and it is allowed to
|
|
* unpin it.
|
|
*/
|
|
sched_pin();
|
|
lock_list = PCPU_GET(spinlocks);
|
|
if (lock_list == NULL || lock_list->ll_count == 0) {
|
|
sched_unpin();
|
|
return;
|
|
}
|
|
sched_unpin();
|
|
}
|
|
|
|
/*
|
|
* Check to see if we are recursing on a lock we already own. If
|
|
* so, make sure that we don't mismatch exclusive and shared lock
|
|
* acquires.
|
|
*/
|
|
lock1 = find_instance(lock_list, lock);
|
|
if (lock1 != NULL) {
|
|
if ((lock1->li_flags & LI_EXCLUSIVE) != 0 &&
|
|
(flags & LOP_EXCLUSIVE) == 0) {
|
|
printf("shared lock of (%s) %s @ %s:%d\n",
|
|
class->lc_name, lock->lo_name, file, line);
|
|
printf("while exclusively locked from %s:%d\n",
|
|
lock1->li_file, lock1->li_line);
|
|
panic("share->excl");
|
|
}
|
|
if ((lock1->li_flags & LI_EXCLUSIVE) == 0 &&
|
|
(flags & LOP_EXCLUSIVE) != 0) {
|
|
printf("exclusive lock of (%s) %s @ %s:%d\n",
|
|
class->lc_name, lock->lo_name, file, line);
|
|
printf("while share locked from %s:%d\n",
|
|
lock1->li_file, lock1->li_line);
|
|
panic("excl->share");
|
|
}
|
|
return;
|
|
}
|
|
|
|
/*
|
|
* Find the previously acquired lock, but ignore interlocks.
|
|
*/
|
|
plock = &lock_list->ll_children[lock_list->ll_count - 1];
|
|
if (interlock != NULL && plock->li_lock == interlock) {
|
|
if (lock_list->ll_count > 1)
|
|
plock =
|
|
&lock_list->ll_children[lock_list->ll_count - 2];
|
|
else {
|
|
lle = lock_list->ll_next;
|
|
|
|
/*
|
|
* The interlock is the only lock we hold, so
|
|
* simply return.
|
|
*/
|
|
if (lle == NULL)
|
|
return;
|
|
plock = &lle->ll_children[lle->ll_count - 1];
|
|
}
|
|
}
|
|
|
|
/*
|
|
* Try to perform most checks without a lock. If this succeeds we
|
|
* can skip acquiring the lock and return success.
|
|
*/
|
|
w1 = plock->li_lock->lo_witness;
|
|
if (witness_lock_order_check(w1, w))
|
|
return;
|
|
|
|
/*
|
|
* Check for duplicate locks of the same type. Note that we only
|
|
* have to check for this on the last lock we just acquired. Any
|
|
* other cases will be caught as lock order violations.
|
|
*/
|
|
mtx_lock_spin(&w_mtx);
|
|
witness_lock_order_add(w1, w);
|
|
if (w1 == w) {
|
|
i = w->w_index;
|
|
if (!(lock->lo_flags & LO_DUPOK) && !(flags & LOP_DUPOK) &&
|
|
!(w_rmatrix[i][i] & WITNESS_REVERSAL)) {
|
|
w_rmatrix[i][i] |= WITNESS_REVERSAL;
|
|
w->w_reversed = 1;
|
|
mtx_unlock_spin(&w_mtx);
|
|
printf(
|
|
"acquiring duplicate lock of same type: \"%s\"\n",
|
|
w->w_name);
|
|
printf(" 1st %s @ %s:%d\n", plock->li_lock->lo_name,
|
|
plock->li_file, plock->li_line);
|
|
printf(" 2nd %s @ %s:%d\n", lock->lo_name, file, line);
|
|
witness_debugger(1);
|
|
} else
|
|
mtx_unlock_spin(&w_mtx);
|
|
return;
|
|
}
|
|
mtx_assert(&w_mtx, MA_OWNED);
|
|
|
|
/*
|
|
* If we know that the the lock we are acquiring comes after
|
|
* the lock we most recently acquired in the lock order tree,
|
|
* then there is no need for any further checks.
|
|
*/
|
|
if (isitmychild(w1, w))
|
|
goto out;
|
|
|
|
for (j = 0, lle = lock_list; lle != NULL; lle = lle->ll_next) {
|
|
for (i = lle->ll_count - 1; i >= 0; i--, j++) {
|
|
|
|
MPASS(j < WITNESS_COUNT);
|
|
lock1 = &lle->ll_children[i];
|
|
|
|
/*
|
|
* Ignore the interlock the first time we see it.
|
|
*/
|
|
if (interlock != NULL && interlock == lock1->li_lock) {
|
|
interlock = NULL;
|
|
continue;
|
|
}
|
|
|
|
/*
|
|
* If this lock doesn't undergo witness checking,
|
|
* then skip it.
|
|
*/
|
|
w1 = lock1->li_lock->lo_witness;
|
|
if (w1 == NULL) {
|
|
KASSERT((lock1->li_lock->lo_flags & LO_WITNESS) == 0,
|
|
("lock missing witness structure"));
|
|
continue;
|
|
}
|
|
|
|
/*
|
|
* If we are locking Giant and this is a sleepable
|
|
* lock, then skip it.
|
|
*/
|
|
if ((lock1->li_lock->lo_flags & LO_SLEEPABLE) != 0 &&
|
|
lock == &Giant.lock_object)
|
|
continue;
|
|
|
|
/*
|
|
* If we are locking a sleepable lock and this lock
|
|
* is Giant, then skip it.
|
|
*/
|
|
if ((lock->lo_flags & LO_SLEEPABLE) != 0 &&
|
|
lock1->li_lock == &Giant.lock_object)
|
|
continue;
|
|
|
|
/*
|
|
* If we are locking a sleepable lock and this lock
|
|
* isn't sleepable, we want to treat it as a lock
|
|
* order violation to enfore a general lock order of
|
|
* sleepable locks before non-sleepable locks.
|
|
*/
|
|
if (((lock->lo_flags & LO_SLEEPABLE) != 0 &&
|
|
(lock1->li_lock->lo_flags & LO_SLEEPABLE) == 0))
|
|
goto reversal;
|
|
|
|
/*
|
|
* If we are locking Giant and this is a non-sleepable
|
|
* lock, then treat it as a reversal.
|
|
*/
|
|
if ((lock1->li_lock->lo_flags & LO_SLEEPABLE) == 0 &&
|
|
lock == &Giant.lock_object)
|
|
goto reversal;
|
|
|
|
/*
|
|
* Check the lock order hierarchy for a reveresal.
|
|
*/
|
|
if (!isitmydescendant(w, w1))
|
|
continue;
|
|
reversal:
|
|
|
|
/*
|
|
* We have a lock order violation, check to see if it
|
|
* is allowed or has already been yelled about.
|
|
*/
|
|
#ifdef BLESSING
|
|
|
|
/*
|
|
* If the lock order is blessed, just bail. We don't
|
|
* look for other lock order violations though, which
|
|
* may be a bug.
|
|
*/
|
|
if (blessed(w, w1))
|
|
goto out;
|
|
#endif
|
|
|
|
/* Bail if this violation is known */
|
|
if (w_rmatrix[w1->w_index][w->w_index] & WITNESS_REVERSAL)
|
|
goto out;
|
|
|
|
/* Record this as a violation */
|
|
w_rmatrix[w1->w_index][w->w_index] |= WITNESS_REVERSAL;
|
|
w_rmatrix[w->w_index][w1->w_index] |= WITNESS_REVERSAL;
|
|
w->w_reversed = w1->w_reversed = 1;
|
|
witness_increment_graph_generation();
|
|
mtx_unlock_spin(&w_mtx);
|
|
|
|
/*
|
|
* Ok, yell about it.
|
|
*/
|
|
if (((lock->lo_flags & LO_SLEEPABLE) != 0 &&
|
|
(lock1->li_lock->lo_flags & LO_SLEEPABLE) == 0))
|
|
printf(
|
|
"lock order reversal: (sleepable after non-sleepable)\n");
|
|
else if ((lock1->li_lock->lo_flags & LO_SLEEPABLE) == 0
|
|
&& lock == &Giant.lock_object)
|
|
printf(
|
|
"lock order reversal: (Giant after non-sleepable)\n");
|
|
else
|
|
printf("lock order reversal:\n");
|
|
|
|
/*
|
|
* Try to locate an earlier lock with
|
|
* witness w in our list.
|
|
*/
|
|
do {
|
|
lock2 = &lle->ll_children[i];
|
|
MPASS(lock2->li_lock != NULL);
|
|
if (lock2->li_lock->lo_witness == w)
|
|
break;
|
|
if (i == 0 && lle->ll_next != NULL) {
|
|
lle = lle->ll_next;
|
|
i = lle->ll_count - 1;
|
|
MPASS(i >= 0 && i < LOCK_NCHILDREN);
|
|
} else
|
|
i--;
|
|
} while (i >= 0);
|
|
if (i < 0) {
|
|
printf(" 1st %p %s (%s) @ %s:%d\n",
|
|
lock1->li_lock, lock1->li_lock->lo_name,
|
|
w1->w_name, lock1->li_file, lock1->li_line);
|
|
printf(" 2nd %p %s (%s) @ %s:%d\n", lock,
|
|
lock->lo_name, w->w_name, file, line);
|
|
} else {
|
|
printf(" 1st %p %s (%s) @ %s:%d\n",
|
|
lock2->li_lock, lock2->li_lock->lo_name,
|
|
lock2->li_lock->lo_witness->w_name,
|
|
lock2->li_file, lock2->li_line);
|
|
printf(" 2nd %p %s (%s) @ %s:%d\n",
|
|
lock1->li_lock, lock1->li_lock->lo_name,
|
|
w1->w_name, lock1->li_file, lock1->li_line);
|
|
printf(" 3rd %p %s (%s) @ %s:%d\n", lock,
|
|
lock->lo_name, w->w_name, file, line);
|
|
}
|
|
witness_debugger(1);
|
|
return;
|
|
}
|
|
}
|
|
|
|
/*
|
|
* If requested, build a new lock order. However, don't build a new
|
|
* relationship between a sleepable lock and Giant if it is in the
|
|
* wrong direction. The correct lock order is that sleepable locks
|
|
* always come before Giant.
|
|
*/
|
|
if (flags & LOP_NEWORDER &&
|
|
!(plock->li_lock == &Giant.lock_object &&
|
|
(lock->lo_flags & LO_SLEEPABLE) != 0)) {
|
|
CTR3(KTR_WITNESS, "%s: adding %s as a child of %s", __func__,
|
|
w->w_name, plock->li_lock->lo_witness->w_name);
|
|
itismychild(plock->li_lock->lo_witness, w);
|
|
}
|
|
out:
|
|
mtx_unlock_spin(&w_mtx);
|
|
}
|
|
|
|
void
|
|
witness_lock(struct lock_object *lock, int flags, const char *file, int line)
|
|
{
|
|
struct lock_list_entry **lock_list, *lle;
|
|
struct lock_instance *instance;
|
|
struct witness *w;
|
|
struct thread *td;
|
|
|
|
if (witness_cold || witness_watch == -1 || lock->lo_witness == NULL ||
|
|
panicstr != NULL)
|
|
return;
|
|
w = lock->lo_witness;
|
|
td = curthread;
|
|
file = fixup_filename(file);
|
|
|
|
/* Determine lock list for this lock. */
|
|
if (LOCK_CLASS(lock)->lc_flags & LC_SLEEPLOCK)
|
|
lock_list = &td->td_sleeplocks;
|
|
else
|
|
lock_list = PCPU_PTR(spinlocks);
|
|
|
|
/* Check to see if we are recursing on a lock we already own. */
|
|
instance = find_instance(*lock_list, lock);
|
|
if (instance != NULL) {
|
|
instance->li_flags++;
|
|
CTR4(KTR_WITNESS, "%s: pid %d recursed on %s r=%d", __func__,
|
|
td->td_proc->p_pid, lock->lo_name,
|
|
instance->li_flags & LI_RECURSEMASK);
|
|
instance->li_file = file;
|
|
instance->li_line = line;
|
|
return;
|
|
}
|
|
|
|
/* Update per-witness last file and line acquire. */
|
|
w->w_file = file;
|
|
w->w_line = line;
|
|
|
|
/* Find the next open lock instance in the list and fill it. */
|
|
lle = *lock_list;
|
|
if (lle == NULL || lle->ll_count == LOCK_NCHILDREN) {
|
|
lle = witness_lock_list_get();
|
|
if (lle == NULL)
|
|
return;
|
|
lle->ll_next = *lock_list;
|
|
CTR3(KTR_WITNESS, "%s: pid %d added lle %p", __func__,
|
|
td->td_proc->p_pid, lle);
|
|
*lock_list = lle;
|
|
}
|
|
instance = &lle->ll_children[lle->ll_count++];
|
|
instance->li_lock = lock;
|
|
instance->li_line = line;
|
|
instance->li_file = file;
|
|
if ((flags & LOP_EXCLUSIVE) != 0)
|
|
instance->li_flags = LI_EXCLUSIVE;
|
|
else
|
|
instance->li_flags = 0;
|
|
CTR4(KTR_WITNESS, "%s: pid %d added %s as lle[%d]", __func__,
|
|
td->td_proc->p_pid, lock->lo_name, lle->ll_count - 1);
|
|
}
|
|
|
|
void
|
|
witness_upgrade(struct lock_object *lock, int flags, const char *file, int line)
|
|
{
|
|
struct lock_instance *instance;
|
|
struct lock_class *class;
|
|
|
|
KASSERT(witness_cold == 0, ("%s: witness_cold", __func__));
|
|
if (lock->lo_witness == NULL || witness_watch == -1 || panicstr != NULL)
|
|
return;
|
|
class = LOCK_CLASS(lock);
|
|
file = fixup_filename(file);
|
|
if (witness_watch) {
|
|
if ((lock->lo_flags & LO_UPGRADABLE) == 0)
|
|
panic("upgrade of non-upgradable lock (%s) %s @ %s:%d",
|
|
class->lc_name, lock->lo_name, file, line);
|
|
if ((class->lc_flags & LC_SLEEPLOCK) == 0)
|
|
panic("upgrade of non-sleep lock (%s) %s @ %s:%d",
|
|
class->lc_name, lock->lo_name, file, line);
|
|
}
|
|
instance = find_instance(curthread->td_sleeplocks, lock);
|
|
if (instance == NULL)
|
|
panic("upgrade of unlocked lock (%s) %s @ %s:%d",
|
|
class->lc_name, lock->lo_name, file, line);
|
|
if (witness_watch) {
|
|
if ((instance->li_flags & LI_EXCLUSIVE) != 0)
|
|
panic("upgrade of exclusive lock (%s) %s @ %s:%d",
|
|
class->lc_name, lock->lo_name, file, line);
|
|
if ((instance->li_flags & LI_RECURSEMASK) != 0)
|
|
panic("upgrade of recursed lock (%s) %s r=%d @ %s:%d",
|
|
class->lc_name, lock->lo_name,
|
|
instance->li_flags & LI_RECURSEMASK, file, line);
|
|
}
|
|
instance->li_flags |= LI_EXCLUSIVE;
|
|
}
|
|
|
|
void
|
|
witness_downgrade(struct lock_object *lock, int flags, const char *file,
|
|
int line)
|
|
{
|
|
struct lock_instance *instance;
|
|
struct lock_class *class;
|
|
|
|
KASSERT(witness_cold == 0, ("%s: witness_cold", __func__));
|
|
if (lock->lo_witness == NULL || witness_watch == -1 || panicstr != NULL)
|
|
return;
|
|
class = LOCK_CLASS(lock);
|
|
file = fixup_filename(file);
|
|
if (witness_watch) {
|
|
if ((lock->lo_flags & LO_UPGRADABLE) == 0)
|
|
panic("downgrade of non-upgradable lock (%s) %s @ %s:%d",
|
|
class->lc_name, lock->lo_name, file, line);
|
|
if ((class->lc_flags & LC_SLEEPLOCK) == 0)
|
|
panic("downgrade of non-sleep lock (%s) %s @ %s:%d",
|
|
class->lc_name, lock->lo_name, file, line);
|
|
}
|
|
instance = find_instance(curthread->td_sleeplocks, lock);
|
|
if (instance == NULL)
|
|
panic("downgrade of unlocked lock (%s) %s @ %s:%d",
|
|
class->lc_name, lock->lo_name, file, line);
|
|
if (witness_watch) {
|
|
if ((instance->li_flags & LI_EXCLUSIVE) == 0)
|
|
panic("downgrade of shared lock (%s) %s @ %s:%d",
|
|
class->lc_name, lock->lo_name, file, line);
|
|
if ((instance->li_flags & LI_RECURSEMASK) != 0)
|
|
panic("downgrade of recursed lock (%s) %s r=%d @ %s:%d",
|
|
class->lc_name, lock->lo_name,
|
|
instance->li_flags & LI_RECURSEMASK, file, line);
|
|
}
|
|
instance->li_flags &= ~LI_EXCLUSIVE;
|
|
}
|
|
|
|
void
|
|
witness_unlock(struct lock_object *lock, int flags, const char *file, int line)
|
|
{
|
|
struct lock_list_entry **lock_list, *lle;
|
|
struct lock_instance *instance;
|
|
struct lock_class *class;
|
|
struct thread *td;
|
|
register_t s;
|
|
int i, j;
|
|
|
|
if (witness_cold || lock->lo_witness == NULL || panicstr != NULL)
|
|
return;
|
|
td = curthread;
|
|
class = LOCK_CLASS(lock);
|
|
file = fixup_filename(file);
|
|
|
|
/* Find lock instance associated with this lock. */
|
|
if (class->lc_flags & LC_SLEEPLOCK)
|
|
lock_list = &td->td_sleeplocks;
|
|
else
|
|
lock_list = PCPU_PTR(spinlocks);
|
|
lle = *lock_list;
|
|
for (; *lock_list != NULL; lock_list = &(*lock_list)->ll_next)
|
|
for (i = 0; i < (*lock_list)->ll_count; i++) {
|
|
instance = &(*lock_list)->ll_children[i];
|
|
if (instance->li_lock == lock)
|
|
goto found;
|
|
}
|
|
|
|
/*
|
|
* When disabling WITNESS through witness_watch we could end up in
|
|
* having registered locks in the td_sleeplocks queue.
|
|
* We have to make sure we flush these queues, so just search for
|
|
* eventual register locks and remove them.
|
|
*/
|
|
if (witness_watch > 0)
|
|
panic("lock (%s) %s not locked @ %s:%d", class->lc_name,
|
|
lock->lo_name, file, line);
|
|
else
|
|
return;
|
|
found:
|
|
|
|
/* First, check for shared/exclusive mismatches. */
|
|
if ((instance->li_flags & LI_EXCLUSIVE) != 0 && witness_watch > 0 &&
|
|
(flags & LOP_EXCLUSIVE) == 0) {
|
|
printf("shared unlock of (%s) %s @ %s:%d\n", class->lc_name,
|
|
lock->lo_name, file, line);
|
|
printf("while exclusively locked from %s:%d\n",
|
|
instance->li_file, instance->li_line);
|
|
panic("excl->ushare");
|
|
}
|
|
if ((instance->li_flags & LI_EXCLUSIVE) == 0 && witness_watch > 0 &&
|
|
(flags & LOP_EXCLUSIVE) != 0) {
|
|
printf("exclusive unlock of (%s) %s @ %s:%d\n", class->lc_name,
|
|
lock->lo_name, file, line);
|
|
printf("while share locked from %s:%d\n", instance->li_file,
|
|
instance->li_line);
|
|
panic("share->uexcl");
|
|
}
|
|
/* If we are recursed, unrecurse. */
|
|
if ((instance->li_flags & LI_RECURSEMASK) > 0) {
|
|
CTR4(KTR_WITNESS, "%s: pid %d unrecursed on %s r=%d", __func__,
|
|
td->td_proc->p_pid, instance->li_lock->lo_name,
|
|
instance->li_flags);
|
|
instance->li_flags--;
|
|
return;
|
|
}
|
|
/* The lock is now being dropped, check for NORELEASE flag */
|
|
if ((instance->li_flags & LI_NORELEASE) != 0 && witness_watch > 0) {
|
|
printf("forbidden unlock of (%s) %s @ %s:%d\n", class->lc_name,
|
|
lock->lo_name, file, line);
|
|
panic("lock marked norelease");
|
|
}
|
|
|
|
/* Otherwise, remove this item from the list. */
|
|
s = intr_disable();
|
|
CTR4(KTR_WITNESS, "%s: pid %d removed %s from lle[%d]", __func__,
|
|
td->td_proc->p_pid, instance->li_lock->lo_name,
|
|
(*lock_list)->ll_count - 1);
|
|
for (j = i; j < (*lock_list)->ll_count - 1; j++)
|
|
(*lock_list)->ll_children[j] =
|
|
(*lock_list)->ll_children[j + 1];
|
|
(*lock_list)->ll_count--;
|
|
intr_restore(s);
|
|
|
|
/*
|
|
* In order to reduce contention on w_mtx, we want to keep always an
|
|
* head object into lists so that frequent allocation from the
|
|
* free witness pool (and subsequent locking) is avoided.
|
|
* In order to maintain the current code simple, when the head
|
|
* object is totally unloaded it means also that we do not have
|
|
* further objects in the list, so the list ownership needs to be
|
|
* hand over to another object if the current head needs to be freed.
|
|
*/
|
|
if ((*lock_list)->ll_count == 0) {
|
|
if (*lock_list == lle) {
|
|
if (lle->ll_next == NULL)
|
|
return;
|
|
} else
|
|
lle = *lock_list;
|
|
*lock_list = lle->ll_next;
|
|
CTR3(KTR_WITNESS, "%s: pid %d removed lle %p", __func__,
|
|
td->td_proc->p_pid, lle);
|
|
witness_lock_list_free(lle);
|
|
}
|
|
}
|
|
|
|
void
|
|
witness_thread_exit(struct thread *td)
|
|
{
|
|
struct lock_list_entry *lle;
|
|
int i, n;
|
|
|
|
lle = td->td_sleeplocks;
|
|
if (lle == NULL || panicstr != NULL)
|
|
return;
|
|
if (lle->ll_count != 0) {
|
|
for (n = 0; lle != NULL; lle = lle->ll_next)
|
|
for (i = lle->ll_count - 1; i >= 0; i--) {
|
|
if (n == 0)
|
|
printf("Thread %p exiting with the following locks held:\n",
|
|
td);
|
|
n++;
|
|
witness_list_lock(&lle->ll_children[i], printf);
|
|
|
|
}
|
|
panic("Thread %p cannot exit while holding sleeplocks\n", td);
|
|
}
|
|
witness_lock_list_free(lle);
|
|
}
|
|
|
|
/*
|
|
* Warn if any locks other than 'lock' are held. Flags can be passed in to
|
|
* exempt Giant and sleepable locks from the checks as well. If any
|
|
* non-exempt locks are held, then a supplied message is printed to the
|
|
* console along with a list of the offending locks. If indicated in the
|
|
* flags then a failure results in a panic as well.
|
|
*/
|
|
int
|
|
witness_warn(int flags, struct lock_object *lock, const char *fmt, ...)
|
|
{
|
|
struct lock_list_entry *lock_list, *lle;
|
|
struct lock_instance *lock1;
|
|
struct thread *td;
|
|
va_list ap;
|
|
int i, n;
|
|
|
|
if (witness_cold || witness_watch < 1 || panicstr != NULL)
|
|
return (0);
|
|
n = 0;
|
|
td = curthread;
|
|
for (lle = td->td_sleeplocks; lle != NULL; lle = lle->ll_next)
|
|
for (i = lle->ll_count - 1; i >= 0; i--) {
|
|
lock1 = &lle->ll_children[i];
|
|
if (lock1->li_lock == lock)
|
|
continue;
|
|
if (flags & WARN_GIANTOK &&
|
|
lock1->li_lock == &Giant.lock_object)
|
|
continue;
|
|
if (flags & WARN_SLEEPOK &&
|
|
(lock1->li_lock->lo_flags & LO_SLEEPABLE) != 0)
|
|
continue;
|
|
if (n == 0) {
|
|
va_start(ap, fmt);
|
|
vprintf(fmt, ap);
|
|
va_end(ap);
|
|
printf(" with the following");
|
|
if (flags & WARN_SLEEPOK)
|
|
printf(" non-sleepable");
|
|
printf(" locks held:\n");
|
|
}
|
|
n++;
|
|
witness_list_lock(lock1, printf);
|
|
}
|
|
|
|
/*
|
|
* Pin the thread in order to avoid problems with thread migration.
|
|
* Once that all verifies are passed about spinlocks ownership,
|
|
* the thread is in a safe path and it can be unpinned.
|
|
*/
|
|
sched_pin();
|
|
lock_list = PCPU_GET(spinlocks);
|
|
if (lock_list != NULL && lock_list->ll_count != 0) {
|
|
sched_unpin();
|
|
|
|
/*
|
|
* We should only have one spinlock and as long as
|
|
* the flags cannot match for this locks class,
|
|
* check if the first spinlock is the one curthread
|
|
* should hold.
|
|
*/
|
|
lock1 = &lock_list->ll_children[lock_list->ll_count - 1];
|
|
if (lock_list->ll_count == 1 && lock_list->ll_next == NULL &&
|
|
lock1->li_lock == lock && n == 0)
|
|
return (0);
|
|
|
|
va_start(ap, fmt);
|
|
vprintf(fmt, ap);
|
|
va_end(ap);
|
|
printf(" with the following");
|
|
if (flags & WARN_SLEEPOK)
|
|
printf(" non-sleepable");
|
|
printf(" locks held:\n");
|
|
n += witness_list_locks(&lock_list, printf);
|
|
} else
|
|
sched_unpin();
|
|
if (flags & WARN_PANIC && n)
|
|
panic("%s", __func__);
|
|
else
|
|
witness_debugger(n);
|
|
return (n);
|
|
}
|
|
|
|
const char *
|
|
witness_file(struct lock_object *lock)
|
|
{
|
|
struct witness *w;
|
|
|
|
if (witness_cold || witness_watch < 1 || lock->lo_witness == NULL)
|
|
return ("?");
|
|
w = lock->lo_witness;
|
|
return (w->w_file);
|
|
}
|
|
|
|
int
|
|
witness_line(struct lock_object *lock)
|
|
{
|
|
struct witness *w;
|
|
|
|
if (witness_cold || witness_watch < 1 || lock->lo_witness == NULL)
|
|
return (0);
|
|
w = lock->lo_witness;
|
|
return (w->w_line);
|
|
}
|
|
|
|
static struct witness *
|
|
enroll(const char *description, struct lock_class *lock_class)
|
|
{
|
|
struct witness *w;
|
|
struct witness_list *typelist;
|
|
|
|
MPASS(description != NULL);
|
|
|
|
if (witness_watch == -1 || panicstr != NULL)
|
|
return (NULL);
|
|
if ((lock_class->lc_flags & LC_SPINLOCK)) {
|
|
if (witness_skipspin)
|
|
return (NULL);
|
|
else
|
|
typelist = &w_spin;
|
|
} else if ((lock_class->lc_flags & LC_SLEEPLOCK))
|
|
typelist = &w_sleep;
|
|
else
|
|
panic("lock class %s is not sleep or spin",
|
|
lock_class->lc_name);
|
|
|
|
mtx_lock_spin(&w_mtx);
|
|
w = witness_hash_get(description);
|
|
if (w)
|
|
goto found;
|
|
if ((w = witness_get()) == NULL)
|
|
return (NULL);
|
|
MPASS(strlen(description) < MAX_W_NAME);
|
|
strcpy(w->w_name, description);
|
|
w->w_class = lock_class;
|
|
w->w_refcount = 1;
|
|
STAILQ_INSERT_HEAD(&w_all, w, w_list);
|
|
if (lock_class->lc_flags & LC_SPINLOCK) {
|
|
STAILQ_INSERT_HEAD(&w_spin, w, w_typelist);
|
|
w_spin_cnt++;
|
|
} else if (lock_class->lc_flags & LC_SLEEPLOCK) {
|
|
STAILQ_INSERT_HEAD(&w_sleep, w, w_typelist);
|
|
w_sleep_cnt++;
|
|
}
|
|
|
|
/* Insert new witness into the hash */
|
|
witness_hash_put(w);
|
|
witness_increment_graph_generation();
|
|
mtx_unlock_spin(&w_mtx);
|
|
return (w);
|
|
found:
|
|
w->w_refcount++;
|
|
mtx_unlock_spin(&w_mtx);
|
|
if (lock_class != w->w_class)
|
|
panic(
|
|
"lock (%s) %s does not match earlier (%s) lock",
|
|
description, lock_class->lc_name,
|
|
w->w_class->lc_name);
|
|
return (w);
|
|
}
|
|
|
|
static void
|
|
depart(struct witness *w)
|
|
{
|
|
struct witness_list *list;
|
|
|
|
MPASS(w->w_refcount == 0);
|
|
if (w->w_class->lc_flags & LC_SLEEPLOCK) {
|
|
list = &w_sleep;
|
|
w_sleep_cnt--;
|
|
} else {
|
|
list = &w_spin;
|
|
w_spin_cnt--;
|
|
}
|
|
/*
|
|
* Set file to NULL as it may point into a loadable module.
|
|
*/
|
|
w->w_file = NULL;
|
|
w->w_line = 0;
|
|
witness_increment_graph_generation();
|
|
}
|
|
|
|
|
|
static void
|
|
adopt(struct witness *parent, struct witness *child)
|
|
{
|
|
int pi, ci, i, j;
|
|
|
|
if (witness_cold == 0)
|
|
mtx_assert(&w_mtx, MA_OWNED);
|
|
|
|
/* If the relationship is already known, there's no work to be done. */
|
|
if (isitmychild(parent, child))
|
|
return;
|
|
|
|
/* When the structure of the graph changes, bump up the generation. */
|
|
witness_increment_graph_generation();
|
|
|
|
/*
|
|
* The hard part ... create the direct relationship, then propagate all
|
|
* indirect relationships.
|
|
*/
|
|
pi = parent->w_index;
|
|
ci = child->w_index;
|
|
WITNESS_INDEX_ASSERT(pi);
|
|
WITNESS_INDEX_ASSERT(ci);
|
|
MPASS(pi != ci);
|
|
w_rmatrix[pi][ci] |= WITNESS_PARENT;
|
|
w_rmatrix[ci][pi] |= WITNESS_CHILD;
|
|
|
|
/*
|
|
* If parent was not already an ancestor of child,
|
|
* then we increment the descendant and ancestor counters.
|
|
*/
|
|
if ((w_rmatrix[pi][ci] & WITNESS_ANCESTOR) == 0) {
|
|
parent->w_num_descendants++;
|
|
child->w_num_ancestors++;
|
|
}
|
|
|
|
/*
|
|
* Find each ancestor of 'pi'. Note that 'pi' itself is counted as
|
|
* an ancestor of 'pi' during this loop.
|
|
*/
|
|
for (i = 1; i <= w_max_used_index; i++) {
|
|
if ((w_rmatrix[i][pi] & WITNESS_ANCESTOR_MASK) == 0 &&
|
|
(i != pi))
|
|
continue;
|
|
|
|
/* Find each descendant of 'i' and mark it as a descendant. */
|
|
for (j = 1; j <= w_max_used_index; j++) {
|
|
|
|
/*
|
|
* Skip children that are already marked as
|
|
* descendants of 'i'.
|
|
*/
|
|
if (w_rmatrix[i][j] & WITNESS_ANCESTOR_MASK)
|
|
continue;
|
|
|
|
/*
|
|
* We are only interested in descendants of 'ci'. Note
|
|
* that 'ci' itself is counted as a descendant of 'ci'.
|
|
*/
|
|
if ((w_rmatrix[ci][j] & WITNESS_ANCESTOR_MASK) == 0 &&
|
|
(j != ci))
|
|
continue;
|
|
w_rmatrix[i][j] |= WITNESS_ANCESTOR;
|
|
w_rmatrix[j][i] |= WITNESS_DESCENDANT;
|
|
w_data[i].w_num_descendants++;
|
|
w_data[j].w_num_ancestors++;
|
|
|
|
/*
|
|
* Make sure we aren't marking a node as both an
|
|
* ancestor and descendant. We should have caught
|
|
* this as a lock order reversal earlier.
|
|
*/
|
|
if ((w_rmatrix[i][j] & WITNESS_ANCESTOR_MASK) &&
|
|
(w_rmatrix[i][j] & WITNESS_DESCENDANT_MASK)) {
|
|
printf("witness rmatrix paradox! [%d][%d]=%d "
|
|
"both ancestor and descendant\n",
|
|
i, j, w_rmatrix[i][j]);
|
|
kdb_backtrace();
|
|
printf("Witness disabled.\n");
|
|
witness_watch = -1;
|
|
}
|
|
if ((w_rmatrix[j][i] & WITNESS_ANCESTOR_MASK) &&
|
|
(w_rmatrix[j][i] & WITNESS_DESCENDANT_MASK)) {
|
|
printf("witness rmatrix paradox! [%d][%d]=%d "
|
|
"both ancestor and descendant\n",
|
|
j, i, w_rmatrix[j][i]);
|
|
kdb_backtrace();
|
|
printf("Witness disabled.\n");
|
|
witness_watch = -1;
|
|
}
|
|
}
|
|
}
|
|
}
|
|
|
|
static void
|
|
itismychild(struct witness *parent, struct witness *child)
|
|
{
|
|
|
|
MPASS(child != NULL && parent != NULL);
|
|
if (witness_cold == 0)
|
|
mtx_assert(&w_mtx, MA_OWNED);
|
|
|
|
if (!witness_lock_type_equal(parent, child)) {
|
|
if (witness_cold == 0)
|
|
mtx_unlock_spin(&w_mtx);
|
|
panic("%s: parent \"%s\" (%s) and child \"%s\" (%s) are not "
|
|
"the same lock type", __func__, parent->w_name,
|
|
parent->w_class->lc_name, child->w_name,
|
|
child->w_class->lc_name);
|
|
}
|
|
adopt(parent, child);
|
|
}
|
|
|
|
/*
|
|
* Generic code for the isitmy*() functions. The rmask parameter is the
|
|
* expected relationship of w1 to w2.
|
|
*/
|
|
static int
|
|
_isitmyx(struct witness *w1, struct witness *w2, int rmask, const char *fname)
|
|
{
|
|
unsigned char r1, r2;
|
|
int i1, i2;
|
|
|
|
i1 = w1->w_index;
|
|
i2 = w2->w_index;
|
|
WITNESS_INDEX_ASSERT(i1);
|
|
WITNESS_INDEX_ASSERT(i2);
|
|
r1 = w_rmatrix[i1][i2] & WITNESS_RELATED_MASK;
|
|
r2 = w_rmatrix[i2][i1] & WITNESS_RELATED_MASK;
|
|
|
|
/* The flags on one better be the inverse of the flags on the other */
|
|
if (!((WITNESS_ATOD(r1) == r2 && WITNESS_DTOA(r2) == r1) ||
|
|
(WITNESS_DTOA(r1) == r2 && WITNESS_ATOD(r2) == r1))) {
|
|
printf("%s: rmatrix mismatch between %s (index %d) and %s "
|
|
"(index %d): w_rmatrix[%d][%d] == %hhx but "
|
|
"w_rmatrix[%d][%d] == %hhx\n",
|
|
fname, w1->w_name, i1, w2->w_name, i2, i1, i2, r1,
|
|
i2, i1, r2);
|
|
kdb_backtrace();
|
|
printf("Witness disabled.\n");
|
|
witness_watch = -1;
|
|
}
|
|
return (r1 & rmask);
|
|
}
|
|
|
|
/*
|
|
* Checks if @child is a direct child of @parent.
|
|
*/
|
|
static int
|
|
isitmychild(struct witness *parent, struct witness *child)
|
|
{
|
|
|
|
return (_isitmyx(parent, child, WITNESS_PARENT, __func__));
|
|
}
|
|
|
|
/*
|
|
* Checks if @descendant is a direct or inderect descendant of @ancestor.
|
|
*/
|
|
static int
|
|
isitmydescendant(struct witness *ancestor, struct witness *descendant)
|
|
{
|
|
|
|
return (_isitmyx(ancestor, descendant, WITNESS_ANCESTOR_MASK,
|
|
__func__));
|
|
}
|
|
|
|
#ifdef BLESSING
|
|
static int
|
|
blessed(struct witness *w1, struct witness *w2)
|
|
{
|
|
int i;
|
|
struct witness_blessed *b;
|
|
|
|
for (i = 0; i < blessed_count; i++) {
|
|
b = &blessed_list[i];
|
|
if (strcmp(w1->w_name, b->b_lock1) == 0) {
|
|
if (strcmp(w2->w_name, b->b_lock2) == 0)
|
|
return (1);
|
|
continue;
|
|
}
|
|
if (strcmp(w1->w_name, b->b_lock2) == 0)
|
|
if (strcmp(w2->w_name, b->b_lock1) == 0)
|
|
return (1);
|
|
}
|
|
return (0);
|
|
}
|
|
#endif
|
|
|
|
static struct witness *
|
|
witness_get(void)
|
|
{
|
|
struct witness *w;
|
|
int index;
|
|
|
|
if (witness_cold == 0)
|
|
mtx_assert(&w_mtx, MA_OWNED);
|
|
|
|
if (witness_watch == -1) {
|
|
mtx_unlock_spin(&w_mtx);
|
|
return (NULL);
|
|
}
|
|
if (STAILQ_EMPTY(&w_free)) {
|
|
witness_watch = -1;
|
|
mtx_unlock_spin(&w_mtx);
|
|
printf("WITNESS: unable to allocate a new witness object\n");
|
|
return (NULL);
|
|
}
|
|
w = STAILQ_FIRST(&w_free);
|
|
STAILQ_REMOVE_HEAD(&w_free, w_list);
|
|
w_free_cnt--;
|
|
index = w->w_index;
|
|
MPASS(index > 0 && index == w_max_used_index+1 &&
|
|
index < WITNESS_COUNT);
|
|
bzero(w, sizeof(*w));
|
|
w->w_index = index;
|
|
if (index > w_max_used_index)
|
|
w_max_used_index = index;
|
|
return (w);
|
|
}
|
|
|
|
static void
|
|
witness_free(struct witness *w)
|
|
{
|
|
|
|
STAILQ_INSERT_HEAD(&w_free, w, w_list);
|
|
w_free_cnt++;
|
|
}
|
|
|
|
static struct lock_list_entry *
|
|
witness_lock_list_get(void)
|
|
{
|
|
struct lock_list_entry *lle;
|
|
|
|
if (witness_watch == -1)
|
|
return (NULL);
|
|
mtx_lock_spin(&w_mtx);
|
|
lle = w_lock_list_free;
|
|
if (lle == NULL) {
|
|
witness_watch = -1;
|
|
mtx_unlock_spin(&w_mtx);
|
|
printf("%s: witness exhausted\n", __func__);
|
|
return (NULL);
|
|
}
|
|
w_lock_list_free = lle->ll_next;
|
|
mtx_unlock_spin(&w_mtx);
|
|
bzero(lle, sizeof(*lle));
|
|
return (lle);
|
|
}
|
|
|
|
static void
|
|
witness_lock_list_free(struct lock_list_entry *lle)
|
|
{
|
|
|
|
mtx_lock_spin(&w_mtx);
|
|
lle->ll_next = w_lock_list_free;
|
|
w_lock_list_free = lle;
|
|
mtx_unlock_spin(&w_mtx);
|
|
}
|
|
|
|
static struct lock_instance *
|
|
find_instance(struct lock_list_entry *list, struct lock_object *lock)
|
|
{
|
|
struct lock_list_entry *lle;
|
|
struct lock_instance *instance;
|
|
int i;
|
|
|
|
for (lle = list; lle != NULL; lle = lle->ll_next)
|
|
for (i = lle->ll_count - 1; i >= 0; i--) {
|
|
instance = &lle->ll_children[i];
|
|
if (instance->li_lock == lock)
|
|
return (instance);
|
|
}
|
|
return (NULL);
|
|
}
|
|
|
|
static void
|
|
witness_list_lock(struct lock_instance *instance,
|
|
int (*prnt)(const char *fmt, ...))
|
|
{
|
|
struct lock_object *lock;
|
|
|
|
lock = instance->li_lock;
|
|
prnt("%s %s %s", (instance->li_flags & LI_EXCLUSIVE) != 0 ?
|
|
"exclusive" : "shared", LOCK_CLASS(lock)->lc_name, lock->lo_name);
|
|
if (lock->lo_witness->w_name != lock->lo_name)
|
|
prnt(" (%s)", lock->lo_witness->w_name);
|
|
prnt(" r = %d (%p) locked @ %s:%d\n",
|
|
instance->li_flags & LI_RECURSEMASK, lock, instance->li_file,
|
|
instance->li_line);
|
|
}
|
|
|
|
#ifdef DDB
|
|
static int
|
|
witness_thread_has_locks(struct thread *td)
|
|
{
|
|
|
|
if (td->td_sleeplocks == NULL)
|
|
return (0);
|
|
return (td->td_sleeplocks->ll_count != 0);
|
|
}
|
|
|
|
static int
|
|
witness_proc_has_locks(struct proc *p)
|
|
{
|
|
struct thread *td;
|
|
|
|
FOREACH_THREAD_IN_PROC(p, td) {
|
|
if (witness_thread_has_locks(td))
|
|
return (1);
|
|
}
|
|
return (0);
|
|
}
|
|
#endif
|
|
|
|
int
|
|
witness_list_locks(struct lock_list_entry **lock_list,
|
|
int (*prnt)(const char *fmt, ...))
|
|
{
|
|
struct lock_list_entry *lle;
|
|
int i, nheld;
|
|
|
|
nheld = 0;
|
|
for (lle = *lock_list; lle != NULL; lle = lle->ll_next)
|
|
for (i = lle->ll_count - 1; i >= 0; i--) {
|
|
witness_list_lock(&lle->ll_children[i], prnt);
|
|
nheld++;
|
|
}
|
|
return (nheld);
|
|
}
|
|
|
|
/*
|
|
* This is a bit risky at best. We call this function when we have timed
|
|
* out acquiring a spin lock, and we assume that the other CPU is stuck
|
|
* with this lock held. So, we go groveling around in the other CPU's
|
|
* per-cpu data to try to find the lock instance for this spin lock to
|
|
* see when it was last acquired.
|
|
*/
|
|
void
|
|
witness_display_spinlock(struct lock_object *lock, struct thread *owner,
|
|
int (*prnt)(const char *fmt, ...))
|
|
{
|
|
struct lock_instance *instance;
|
|
struct pcpu *pc;
|
|
|
|
if (owner->td_critnest == 0 || owner->td_oncpu == NOCPU)
|
|
return;
|
|
pc = pcpu_find(owner->td_oncpu);
|
|
instance = find_instance(pc->pc_spinlocks, lock);
|
|
if (instance != NULL)
|
|
witness_list_lock(instance, prnt);
|
|
}
|
|
|
|
void
|
|
witness_save(struct lock_object *lock, const char **filep, int *linep)
|
|
{
|
|
struct lock_list_entry *lock_list;
|
|
struct lock_instance *instance;
|
|
struct lock_class *class;
|
|
|
|
KASSERT(witness_cold == 0, ("%s: witness_cold", __func__));
|
|
if (lock->lo_witness == NULL || witness_watch == -1 || panicstr != NULL)
|
|
return;
|
|
class = LOCK_CLASS(lock);
|
|
if (class->lc_flags & LC_SLEEPLOCK)
|
|
lock_list = curthread->td_sleeplocks;
|
|
else {
|
|
if (witness_skipspin)
|
|
return;
|
|
lock_list = PCPU_GET(spinlocks);
|
|
}
|
|
instance = find_instance(lock_list, lock);
|
|
if (instance == NULL)
|
|
panic("%s: lock (%s) %s not locked", __func__,
|
|
class->lc_name, lock->lo_name);
|
|
*filep = instance->li_file;
|
|
*linep = instance->li_line;
|
|
}
|
|
|
|
void
|
|
witness_restore(struct lock_object *lock, const char *file, int line)
|
|
{
|
|
struct lock_list_entry *lock_list;
|
|
struct lock_instance *instance;
|
|
struct lock_class *class;
|
|
|
|
KASSERT(witness_cold == 0, ("%s: witness_cold", __func__));
|
|
if (lock->lo_witness == NULL || witness_watch == -1 || panicstr != NULL)
|
|
return;
|
|
class = LOCK_CLASS(lock);
|
|
if (class->lc_flags & LC_SLEEPLOCK)
|
|
lock_list = curthread->td_sleeplocks;
|
|
else {
|
|
if (witness_skipspin)
|
|
return;
|
|
lock_list = PCPU_GET(spinlocks);
|
|
}
|
|
instance = find_instance(lock_list, lock);
|
|
if (instance == NULL)
|
|
panic("%s: lock (%s) %s not locked", __func__,
|
|
class->lc_name, lock->lo_name);
|
|
lock->lo_witness->w_file = file;
|
|
lock->lo_witness->w_line = line;
|
|
instance->li_file = file;
|
|
instance->li_line = line;
|
|
}
|
|
|
|
void
|
|
witness_assert(struct lock_object *lock, int flags, const char *file, int line)
|
|
{
|
|
#ifdef INVARIANT_SUPPORT
|
|
struct lock_instance *instance;
|
|
struct lock_class *class;
|
|
|
|
if (lock->lo_witness == NULL || witness_watch < 1 || panicstr != NULL)
|
|
return;
|
|
class = LOCK_CLASS(lock);
|
|
if ((class->lc_flags & LC_SLEEPLOCK) != 0)
|
|
instance = find_instance(curthread->td_sleeplocks, lock);
|
|
else if ((class->lc_flags & LC_SPINLOCK) != 0)
|
|
instance = find_instance(PCPU_GET(spinlocks), lock);
|
|
else {
|
|
panic("Lock (%s) %s is not sleep or spin!",
|
|
class->lc_name, lock->lo_name);
|
|
}
|
|
file = fixup_filename(file);
|
|
switch (flags) {
|
|
case LA_UNLOCKED:
|
|
if (instance != NULL)
|
|
panic("Lock (%s) %s locked @ %s:%d.",
|
|
class->lc_name, lock->lo_name, file, line);
|
|
break;
|
|
case LA_LOCKED:
|
|
case LA_LOCKED | LA_RECURSED:
|
|
case LA_LOCKED | LA_NOTRECURSED:
|
|
case LA_SLOCKED:
|
|
case LA_SLOCKED | LA_RECURSED:
|
|
case LA_SLOCKED | LA_NOTRECURSED:
|
|
case LA_XLOCKED:
|
|
case LA_XLOCKED | LA_RECURSED:
|
|
case LA_XLOCKED | LA_NOTRECURSED:
|
|
if (instance == NULL) {
|
|
panic("Lock (%s) %s not locked @ %s:%d.",
|
|
class->lc_name, lock->lo_name, file, line);
|
|
break;
|
|
}
|
|
if ((flags & LA_XLOCKED) != 0 &&
|
|
(instance->li_flags & LI_EXCLUSIVE) == 0)
|
|
panic("Lock (%s) %s not exclusively locked @ %s:%d.",
|
|
class->lc_name, lock->lo_name, file, line);
|
|
if ((flags & LA_SLOCKED) != 0 &&
|
|
(instance->li_flags & LI_EXCLUSIVE) != 0)
|
|
panic("Lock (%s) %s exclusively locked @ %s:%d.",
|
|
class->lc_name, lock->lo_name, file, line);
|
|
if ((flags & LA_RECURSED) != 0 &&
|
|
(instance->li_flags & LI_RECURSEMASK) == 0)
|
|
panic("Lock (%s) %s not recursed @ %s:%d.",
|
|
class->lc_name, lock->lo_name, file, line);
|
|
if ((flags & LA_NOTRECURSED) != 0 &&
|
|
(instance->li_flags & LI_RECURSEMASK) != 0)
|
|
panic("Lock (%s) %s recursed @ %s:%d.",
|
|
class->lc_name, lock->lo_name, file, line);
|
|
break;
|
|
default:
|
|
panic("Invalid lock assertion at %s:%d.", file, line);
|
|
|
|
}
|
|
#endif /* INVARIANT_SUPPORT */
|
|
}
|
|
|
|
static void
|
|
witness_setflag(struct lock_object *lock, int flag, int set)
|
|
{
|
|
struct lock_list_entry *lock_list;
|
|
struct lock_instance *instance;
|
|
struct lock_class *class;
|
|
|
|
if (lock->lo_witness == NULL || witness_watch == -1 || panicstr != NULL)
|
|
return;
|
|
class = LOCK_CLASS(lock);
|
|
if (class->lc_flags & LC_SLEEPLOCK)
|
|
lock_list = curthread->td_sleeplocks;
|
|
else {
|
|
if (witness_skipspin)
|
|
return;
|
|
lock_list = PCPU_GET(spinlocks);
|
|
}
|
|
instance = find_instance(lock_list, lock);
|
|
if (instance == NULL)
|
|
panic("%s: lock (%s) %s not locked", __func__,
|
|
class->lc_name, lock->lo_name);
|
|
|
|
if (set)
|
|
instance->li_flags |= flag;
|
|
else
|
|
instance->li_flags &= ~flag;
|
|
}
|
|
|
|
void
|
|
witness_norelease(struct lock_object *lock)
|
|
{
|
|
|
|
witness_setflag(lock, LI_NORELEASE, 1);
|
|
}
|
|
|
|
void
|
|
witness_releaseok(struct lock_object *lock)
|
|
{
|
|
|
|
witness_setflag(lock, LI_NORELEASE, 0);
|
|
}
|
|
|
|
#ifdef DDB
|
|
static void
|
|
witness_ddb_list(struct thread *td)
|
|
{
|
|
|
|
KASSERT(witness_cold == 0, ("%s: witness_cold", __func__));
|
|
KASSERT(kdb_active, ("%s: not in the debugger", __func__));
|
|
|
|
if (witness_watch < 1)
|
|
return;
|
|
|
|
witness_list_locks(&td->td_sleeplocks, db_printf);
|
|
|
|
/*
|
|
* We only handle spinlocks if td == curthread. This is somewhat broken
|
|
* if td is currently executing on some other CPU and holds spin locks
|
|
* as we won't display those locks. If we had a MI way of getting
|
|
* the per-cpu data for a given cpu then we could use
|
|
* td->td_oncpu to get the list of spinlocks for this thread
|
|
* and "fix" this.
|
|
*
|
|
* That still wouldn't really fix this unless we locked the scheduler
|
|
* lock or stopped the other CPU to make sure it wasn't changing the
|
|
* list out from under us. It is probably best to just not try to
|
|
* handle threads on other CPU's for now.
|
|
*/
|
|
if (td == curthread && PCPU_GET(spinlocks) != NULL)
|
|
witness_list_locks(PCPU_PTR(spinlocks), db_printf);
|
|
}
|
|
|
|
DB_SHOW_COMMAND(locks, db_witness_list)
|
|
{
|
|
struct thread *td;
|
|
|
|
if (have_addr)
|
|
td = db_lookup_thread(addr, TRUE);
|
|
else
|
|
td = kdb_thread;
|
|
witness_ddb_list(td);
|
|
}
|
|
|
|
DB_SHOW_ALL_COMMAND(locks, db_witness_list_all)
|
|
{
|
|
struct thread *td;
|
|
struct proc *p;
|
|
|
|
/*
|
|
* It would be nice to list only threads and processes that actually
|
|
* held sleep locks, but that information is currently not exported
|
|
* by WITNESS.
|
|
*/
|
|
FOREACH_PROC_IN_SYSTEM(p) {
|
|
if (!witness_proc_has_locks(p))
|
|
continue;
|
|
FOREACH_THREAD_IN_PROC(p, td) {
|
|
if (!witness_thread_has_locks(td))
|
|
continue;
|
|
db_printf("Process %d (%s) thread %p (%d)\n", p->p_pid,
|
|
p->p_comm, td, td->td_tid);
|
|
witness_ddb_list(td);
|
|
}
|
|
}
|
|
}
|
|
DB_SHOW_ALIAS(alllocks, db_witness_list_all)
|
|
|
|
DB_SHOW_COMMAND(witness, db_witness_display)
|
|
{
|
|
|
|
witness_ddb_display(db_printf);
|
|
}
|
|
#endif
|
|
|
|
static int
|
|
sysctl_debug_witness_badstacks(SYSCTL_HANDLER_ARGS)
|
|
{
|
|
struct witness_lock_order_data *data1, *data2, *tmp_data1, *tmp_data2;
|
|
struct witness *tmp_w1, *tmp_w2, *w1, *w2;
|
|
struct sbuf *sb;
|
|
u_int w_rmatrix1, w_rmatrix2;
|
|
int error, generation, i, j;
|
|
|
|
tmp_data1 = NULL;
|
|
tmp_data2 = NULL;
|
|
tmp_w1 = NULL;
|
|
tmp_w2 = NULL;
|
|
if (witness_watch < 1) {
|
|
error = SYSCTL_OUT(req, w_notrunning, sizeof(w_notrunning));
|
|
return (error);
|
|
}
|
|
if (witness_cold) {
|
|
error = SYSCTL_OUT(req, w_stillcold, sizeof(w_stillcold));
|
|
return (error);
|
|
}
|
|
error = 0;
|
|
sb = sbuf_new(NULL, NULL, BADSTACK_SBUF_SIZE, SBUF_AUTOEXTEND);
|
|
if (sb == NULL)
|
|
return (ENOMEM);
|
|
|
|
/* Allocate and init temporary storage space. */
|
|
tmp_w1 = malloc(sizeof(struct witness), M_TEMP, M_WAITOK | M_ZERO);
|
|
tmp_w2 = malloc(sizeof(struct witness), M_TEMP, M_WAITOK | M_ZERO);
|
|
tmp_data1 = malloc(sizeof(struct witness_lock_order_data), M_TEMP,
|
|
M_WAITOK | M_ZERO);
|
|
tmp_data2 = malloc(sizeof(struct witness_lock_order_data), M_TEMP,
|
|
M_WAITOK | M_ZERO);
|
|
stack_zero(&tmp_data1->wlod_stack);
|
|
stack_zero(&tmp_data2->wlod_stack);
|
|
|
|
restart:
|
|
mtx_lock_spin(&w_mtx);
|
|
generation = w_generation;
|
|
mtx_unlock_spin(&w_mtx);
|
|
sbuf_printf(sb, "Number of known direct relationships is %d\n",
|
|
w_lohash.wloh_count);
|
|
for (i = 1; i < w_max_used_index; i++) {
|
|
mtx_lock_spin(&w_mtx);
|
|
if (generation != w_generation) {
|
|
mtx_unlock_spin(&w_mtx);
|
|
|
|
/* The graph has changed, try again. */
|
|
req->oldidx = 0;
|
|
sbuf_clear(sb);
|
|
goto restart;
|
|
}
|
|
|
|
w1 = &w_data[i];
|
|
if (w1->w_reversed == 0) {
|
|
mtx_unlock_spin(&w_mtx);
|
|
continue;
|
|
}
|
|
|
|
/* Copy w1 locally so we can release the spin lock. */
|
|
*tmp_w1 = *w1;
|
|
mtx_unlock_spin(&w_mtx);
|
|
|
|
if (tmp_w1->w_reversed == 0)
|
|
continue;
|
|
for (j = 1; j < w_max_used_index; j++) {
|
|
if ((w_rmatrix[i][j] & WITNESS_REVERSAL) == 0 || i > j)
|
|
continue;
|
|
|
|
mtx_lock_spin(&w_mtx);
|
|
if (generation != w_generation) {
|
|
mtx_unlock_spin(&w_mtx);
|
|
|
|
/* The graph has changed, try again. */
|
|
req->oldidx = 0;
|
|
sbuf_clear(sb);
|
|
goto restart;
|
|
}
|
|
|
|
w2 = &w_data[j];
|
|
data1 = witness_lock_order_get(w1, w2);
|
|
data2 = witness_lock_order_get(w2, w1);
|
|
|
|
/*
|
|
* Copy information locally so we can release the
|
|
* spin lock.
|
|
*/
|
|
*tmp_w2 = *w2;
|
|
w_rmatrix1 = (unsigned int)w_rmatrix[i][j];
|
|
w_rmatrix2 = (unsigned int)w_rmatrix[j][i];
|
|
|
|
if (data1) {
|
|
stack_zero(&tmp_data1->wlod_stack);
|
|
stack_copy(&data1->wlod_stack,
|
|
&tmp_data1->wlod_stack);
|
|
}
|
|
if (data2 && data2 != data1) {
|
|
stack_zero(&tmp_data2->wlod_stack);
|
|
stack_copy(&data2->wlod_stack,
|
|
&tmp_data2->wlod_stack);
|
|
}
|
|
mtx_unlock_spin(&w_mtx);
|
|
|
|
sbuf_printf(sb,
|
|
"\nLock order reversal between \"%s\"(%s) and \"%s\"(%s)!\n",
|
|
tmp_w1->w_name, tmp_w1->w_class->lc_name,
|
|
tmp_w2->w_name, tmp_w2->w_class->lc_name);
|
|
#if 0
|
|
sbuf_printf(sb,
|
|
"w_rmatrix[%s][%s] == %x, w_rmatrix[%s][%s] == %x\n",
|
|
tmp_w1->name, tmp_w2->w_name, w_rmatrix1,
|
|
tmp_w2->name, tmp_w1->w_name, w_rmatrix2);
|
|
#endif
|
|
if (data1) {
|
|
sbuf_printf(sb,
|
|
"Lock order \"%s\"(%s) -> \"%s\"(%s) first seen at:\n",
|
|
tmp_w1->w_name, tmp_w1->w_class->lc_name,
|
|
tmp_w2->w_name, tmp_w2->w_class->lc_name);
|
|
stack_sbuf_print(sb, &tmp_data1->wlod_stack);
|
|
sbuf_printf(sb, "\n");
|
|
}
|
|
if (data2 && data2 != data1) {
|
|
sbuf_printf(sb,
|
|
"Lock order \"%s\"(%s) -> \"%s\"(%s) first seen at:\n",
|
|
tmp_w2->w_name, tmp_w2->w_class->lc_name,
|
|
tmp_w1->w_name, tmp_w1->w_class->lc_name);
|
|
stack_sbuf_print(sb, &tmp_data2->wlod_stack);
|
|
sbuf_printf(sb, "\n");
|
|
}
|
|
}
|
|
}
|
|
mtx_lock_spin(&w_mtx);
|
|
if (generation != w_generation) {
|
|
mtx_unlock_spin(&w_mtx);
|
|
|
|
/*
|
|
* The graph changed while we were printing stack data,
|
|
* try again.
|
|
*/
|
|
req->oldidx = 0;
|
|
sbuf_clear(sb);
|
|
goto restart;
|
|
}
|
|
mtx_unlock_spin(&w_mtx);
|
|
|
|
/* Free temporary storage space. */
|
|
free(tmp_data1, M_TEMP);
|
|
free(tmp_data2, M_TEMP);
|
|
free(tmp_w1, M_TEMP);
|
|
free(tmp_w2, M_TEMP);
|
|
|
|
sbuf_finish(sb);
|
|
error = SYSCTL_OUT(req, sbuf_data(sb), sbuf_len(sb) + 1);
|
|
sbuf_delete(sb);
|
|
|
|
return (error);
|
|
}
|
|
|
|
static int
|
|
sysctl_debug_witness_fullgraph(SYSCTL_HANDLER_ARGS)
|
|
{
|
|
struct witness *w;
|
|
struct sbuf *sb;
|
|
int error;
|
|
|
|
if (witness_watch < 1) {
|
|
error = SYSCTL_OUT(req, w_notrunning, sizeof(w_notrunning));
|
|
return (error);
|
|
}
|
|
if (witness_cold) {
|
|
error = SYSCTL_OUT(req, w_stillcold, sizeof(w_stillcold));
|
|
return (error);
|
|
}
|
|
error = 0;
|
|
sb = sbuf_new(NULL, NULL, FULLGRAPH_SBUF_SIZE, SBUF_FIXEDLEN);
|
|
if (sb == NULL)
|
|
return (ENOMEM);
|
|
sbuf_printf(sb, "\n");
|
|
|
|
mtx_lock_spin(&w_mtx);
|
|
STAILQ_FOREACH(w, &w_all, w_list)
|
|
w->w_displayed = 0;
|
|
STAILQ_FOREACH(w, &w_all, w_list)
|
|
witness_add_fullgraph(sb, w);
|
|
mtx_unlock_spin(&w_mtx);
|
|
|
|
/*
|
|
* While using SBUF_FIXEDLEN, check if the sbuf overflowed.
|
|
*/
|
|
if (sbuf_overflowed(sb)) {
|
|
sbuf_delete(sb);
|
|
panic("%s: sbuf overflowed, bump FULLGRAPH_SBUF_SIZE value\n",
|
|
__func__);
|
|
}
|
|
|
|
/*
|
|
* Close the sbuf and return to userland.
|
|
*/
|
|
sbuf_finish(sb);
|
|
error = SYSCTL_OUT(req, sbuf_data(sb), sbuf_len(sb) + 1);
|
|
sbuf_delete(sb);
|
|
|
|
return (error);
|
|
}
|
|
|
|
static int
|
|
sysctl_debug_witness_watch(SYSCTL_HANDLER_ARGS)
|
|
{
|
|
int error, value;
|
|
|
|
value = witness_watch;
|
|
error = sysctl_handle_int(oidp, &value, 0, req);
|
|
if (error != 0 || req->newptr == NULL)
|
|
return (error);
|
|
if (value > 1 || value < -1 ||
|
|
(witness_watch == -1 && value != witness_watch))
|
|
return (EINVAL);
|
|
witness_watch = value;
|
|
return (0);
|
|
}
|
|
|
|
static void
|
|
witness_add_fullgraph(struct sbuf *sb, struct witness *w)
|
|
{
|
|
int i;
|
|
|
|
if (w->w_displayed != 0 || (w->w_file == NULL && w->w_line == 0))
|
|
return;
|
|
w->w_displayed = 1;
|
|
|
|
WITNESS_INDEX_ASSERT(w->w_index);
|
|
for (i = 1; i <= w_max_used_index; i++) {
|
|
if (w_rmatrix[w->w_index][i] & WITNESS_PARENT) {
|
|
sbuf_printf(sb, "\"%s\",\"%s\"\n", w->w_name,
|
|
w_data[i].w_name);
|
|
witness_add_fullgraph(sb, &w_data[i]);
|
|
}
|
|
}
|
|
}
|
|
|
|
/*
|
|
* A simple hash function. Takes a key pointer and a key size. If size == 0,
|
|
* interprets the key as a string and reads until the null
|
|
* terminator. Otherwise, reads the first size bytes. Returns an unsigned 32-bit
|
|
* hash value computed from the key.
|
|
*/
|
|
static uint32_t
|
|
witness_hash_djb2(const uint8_t *key, uint32_t size)
|
|
{
|
|
unsigned int hash = 5381;
|
|
int i;
|
|
|
|
/* hash = hash * 33 + key[i] */
|
|
if (size)
|
|
for (i = 0; i < size; i++)
|
|
hash = ((hash << 5) + hash) + (unsigned int)key[i];
|
|
else
|
|
for (i = 0; key[i] != 0; i++)
|
|
hash = ((hash << 5) + hash) + (unsigned int)key[i];
|
|
|
|
return (hash);
|
|
}
|
|
|
|
|
|
/*
|
|
* Initializes the two witness hash tables. Called exactly once from
|
|
* witness_initialize().
|
|
*/
|
|
static void
|
|
witness_init_hash_tables(void)
|
|
{
|
|
int i;
|
|
|
|
MPASS(witness_cold);
|
|
|
|
/* Initialize the hash tables. */
|
|
for (i = 0; i < WITNESS_HASH_SIZE; i++)
|
|
w_hash.wh_array[i] = NULL;
|
|
|
|
w_hash.wh_size = WITNESS_HASH_SIZE;
|
|
w_hash.wh_count = 0;
|
|
|
|
/* Initialize the lock order data hash. */
|
|
w_lofree = NULL;
|
|
for (i = 0; i < WITNESS_LO_DATA_COUNT; i++) {
|
|
memset(&w_lodata[i], 0, sizeof(w_lodata[i]));
|
|
w_lodata[i].wlod_next = w_lofree;
|
|
w_lofree = &w_lodata[i];
|
|
}
|
|
w_lohash.wloh_size = WITNESS_LO_HASH_SIZE;
|
|
w_lohash.wloh_count = 0;
|
|
for (i = 0; i < WITNESS_LO_HASH_SIZE; i++)
|
|
w_lohash.wloh_array[i] = NULL;
|
|
}
|
|
|
|
static struct witness *
|
|
witness_hash_get(const char *key)
|
|
{
|
|
struct witness *w;
|
|
uint32_t hash;
|
|
|
|
MPASS(key != NULL);
|
|
if (witness_cold == 0)
|
|
mtx_assert(&w_mtx, MA_OWNED);
|
|
hash = witness_hash_djb2(key, 0) % w_hash.wh_size;
|
|
w = w_hash.wh_array[hash];
|
|
while (w != NULL) {
|
|
if (strcmp(w->w_name, key) == 0)
|
|
goto out;
|
|
w = w->w_hash_next;
|
|
}
|
|
|
|
out:
|
|
return (w);
|
|
}
|
|
|
|
static void
|
|
witness_hash_put(struct witness *w)
|
|
{
|
|
uint32_t hash;
|
|
|
|
MPASS(w != NULL);
|
|
MPASS(w->w_name != NULL);
|
|
if (witness_cold == 0)
|
|
mtx_assert(&w_mtx, MA_OWNED);
|
|
KASSERT(witness_hash_get(w->w_name) == NULL,
|
|
("%s: trying to add a hash entry that already exists!", __func__));
|
|
KASSERT(w->w_hash_next == NULL,
|
|
("%s: w->w_hash_next != NULL", __func__));
|
|
|
|
hash = witness_hash_djb2(w->w_name, 0) % w_hash.wh_size;
|
|
w->w_hash_next = w_hash.wh_array[hash];
|
|
w_hash.wh_array[hash] = w;
|
|
w_hash.wh_count++;
|
|
}
|
|
|
|
|
|
static struct witness_lock_order_data *
|
|
witness_lock_order_get(struct witness *parent, struct witness *child)
|
|
{
|
|
struct witness_lock_order_data *data = NULL;
|
|
struct witness_lock_order_key key;
|
|
unsigned int hash;
|
|
|
|
MPASS(parent != NULL && child != NULL);
|
|
key.from = parent->w_index;
|
|
key.to = child->w_index;
|
|
WITNESS_INDEX_ASSERT(key.from);
|
|
WITNESS_INDEX_ASSERT(key.to);
|
|
if ((w_rmatrix[parent->w_index][child->w_index]
|
|
& WITNESS_LOCK_ORDER_KNOWN) == 0)
|
|
goto out;
|
|
|
|
hash = witness_hash_djb2((const char*)&key,
|
|
sizeof(key)) % w_lohash.wloh_size;
|
|
data = w_lohash.wloh_array[hash];
|
|
while (data != NULL) {
|
|
if (witness_lock_order_key_equal(&data->wlod_key, &key))
|
|
break;
|
|
data = data->wlod_next;
|
|
}
|
|
|
|
out:
|
|
return (data);
|
|
}
|
|
|
|
/*
|
|
* Verify that parent and child have a known relationship, are not the same,
|
|
* and child is actually a child of parent. This is done without w_mtx
|
|
* to avoid contention in the common case.
|
|
*/
|
|
static int
|
|
witness_lock_order_check(struct witness *parent, struct witness *child)
|
|
{
|
|
|
|
if (parent != child &&
|
|
w_rmatrix[parent->w_index][child->w_index]
|
|
& WITNESS_LOCK_ORDER_KNOWN &&
|
|
isitmychild(parent, child))
|
|
return (1);
|
|
|
|
return (0);
|
|
}
|
|
|
|
static int
|
|
witness_lock_order_add(struct witness *parent, struct witness *child)
|
|
{
|
|
struct witness_lock_order_data *data = NULL;
|
|
struct witness_lock_order_key key;
|
|
unsigned int hash;
|
|
|
|
MPASS(parent != NULL && child != NULL);
|
|
key.from = parent->w_index;
|
|
key.to = child->w_index;
|
|
WITNESS_INDEX_ASSERT(key.from);
|
|
WITNESS_INDEX_ASSERT(key.to);
|
|
if (w_rmatrix[parent->w_index][child->w_index]
|
|
& WITNESS_LOCK_ORDER_KNOWN)
|
|
return (1);
|
|
|
|
hash = witness_hash_djb2((const char*)&key,
|
|
sizeof(key)) % w_lohash.wloh_size;
|
|
w_rmatrix[parent->w_index][child->w_index] |= WITNESS_LOCK_ORDER_KNOWN;
|
|
data = w_lofree;
|
|
if (data == NULL)
|
|
return (0);
|
|
w_lofree = data->wlod_next;
|
|
data->wlod_next = w_lohash.wloh_array[hash];
|
|
data->wlod_key = key;
|
|
w_lohash.wloh_array[hash] = data;
|
|
w_lohash.wloh_count++;
|
|
stack_zero(&data->wlod_stack);
|
|
stack_save(&data->wlod_stack);
|
|
return (1);
|
|
}
|
|
|
|
/* Call this whenver the structure of the witness graph changes. */
|
|
static void
|
|
witness_increment_graph_generation(void)
|
|
{
|
|
|
|
if (witness_cold == 0)
|
|
mtx_assert(&w_mtx, MA_OWNED);
|
|
w_generation++;
|
|
}
|
|
|
|
#ifdef KDB
|
|
static void
|
|
_witness_debugger(int cond, const char *msg)
|
|
{
|
|
|
|
if (witness_trace && cond)
|
|
kdb_backtrace();
|
|
if (witness_kdb && cond)
|
|
kdb_enter(KDB_WHY_WITNESS, msg);
|
|
}
|
|
#endif
|