1681 lines
39 KiB
C
1681 lines
39 KiB
C
/*-
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* Copyright (c) 1998 Berkeley Software Design, Inc. 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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* $FreeBSD$
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*/
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/*
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* Machine independent bits of mutex implementation and implementation of
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* `witness' structure & related debugging routines.
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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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#include "opt_ddb.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/kernel.h>
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#include <sys/malloc.h>
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#include <sys/proc.h>
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#include <sys/sysctl.h>
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#include <sys/systm.h>
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#include <sys/vmmeter.h>
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#include <sys/ktr.h>
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#include <machine/atomic.h>
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#include <machine/bus.h>
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#include <machine/clock.h>
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#include <machine/cpu.h>
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#include <ddb/ddb.h>
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#include <vm/vm.h>
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#include <vm/vm_extern.h>
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#include <sys/mutex.h>
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/*
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* The WITNESS-enabled mutex debug structure.
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*/
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#ifdef WITNESS
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struct mtx_debug {
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struct witness *mtxd_witness;
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LIST_ENTRY(mtx) mtxd_held;
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const char *mtxd_file;
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int mtxd_line;
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};
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#define mtx_held mtx_debug->mtxd_held
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#define mtx_file mtx_debug->mtxd_file
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#define mtx_line mtx_debug->mtxd_line
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#define mtx_witness mtx_debug->mtxd_witness
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#endif /* WITNESS */
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/*
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* Internal utility macros.
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*/
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#define mtx_unowned(m) ((m)->mtx_lock == MTX_UNOWNED)
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#define mtx_owner(m) (mtx_unowned((m)) ? NULL \
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: (struct proc *)((m)->mtx_lock & MTX_FLAGMASK))
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#define RETIP(x) *(((uintptr_t *)(&x)) - 1)
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#define SET_PRIO(p, pri) (p)->p_pri.pri_level = (pri)
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/*
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* Early WITNESS-enabled declarations.
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*/
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#ifdef WITNESS
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/*
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* Internal WITNESS routines which must be prototyped early.
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*
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* XXX: When/if witness code is cleaned up, it would be wise to place all
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* witness prototyping early in this file.
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*/
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static void witness_init(struct mtx *, int flag);
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static void witness_destroy(struct mtx *);
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static void witness_display(void(*)(const char *fmt, ...));
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MALLOC_DEFINE(M_WITNESS, "witness", "witness mtx_debug structure");
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/* All mutexes in system (used for debug/panic) */
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static struct mtx_debug all_mtx_debug = { NULL, {NULL, NULL}, NULL, 0 };
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/*
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* This global is set to 0 once it becomes safe to use the witness code.
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*/
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static int witness_cold = 1;
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#else /* WITNESS */
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/* XXX XXX XXX
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* flag++ is sleazoid way of shuting up warning
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*/
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#define witness_init(m, flag) flag++
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#define witness_destroy(m)
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#define witness_try_enter(m, t, f, l)
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#endif /* WITNESS */
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/*
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* All mutex locks in system are kept on the all_mtx list.
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*/
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static struct mtx all_mtx = { MTX_UNOWNED, 0, 0, 0, "All mutexes queue head",
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TAILQ_HEAD_INITIALIZER(all_mtx.mtx_blocked),
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{ NULL, NULL }, &all_mtx, &all_mtx,
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#ifdef WITNESS
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&all_mtx_debug
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#else
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NULL
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#endif
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};
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/*
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* Global variables for book keeping.
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*/
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static int mtx_cur_cnt;
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static int mtx_max_cnt;
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/*
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* Couple of strings for KTR_LOCK tracing in order to avoid duplicates.
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*/
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char STR_mtx_lock_slp[] = "GOT (sleep) %s [%p] r=%d at %s:%d";
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char STR_mtx_unlock_slp[] = "REL (sleep) %s [%p] r=%d at %s:%d";
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char STR_mtx_lock_spn[] = "GOT (spin) %s [%p] r=%d at %s:%d";
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char STR_mtx_unlock_spn[] = "REL (spin) %s [%p] r=%d at %s:%d";
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/*
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* Prototypes for non-exported routines.
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*
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* NOTE: Prototypes for witness routines are placed at the bottom of the file.
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*/
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static void propagate_priority(struct proc *);
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static void
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propagate_priority(struct proc *p)
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{
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int pri = p->p_pri.pri_level;
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struct mtx *m = p->p_blocked;
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mtx_assert(&sched_lock, MA_OWNED);
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for (;;) {
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struct proc *p1;
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p = mtx_owner(m);
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if (p == NULL) {
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/*
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* This really isn't quite right. Really
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* ought to bump priority of process that
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* next acquires the mutex.
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*/
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MPASS(m->mtx_lock == MTX_CONTESTED);
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return;
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}
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MPASS(p->p_magic == P_MAGIC);
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KASSERT(p->p_stat != SSLEEP, ("sleeping process owns a mutex"));
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if (p->p_pri.pri_level <= pri)
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return;
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/*
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* Bump this process' priority.
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*/
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SET_PRIO(p, pri);
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/*
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* If lock holder is actually running, just bump priority.
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*/
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if (p->p_oncpu != 0xff) {
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MPASS(p->p_stat == SRUN || p->p_stat == SZOMB);
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return;
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}
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/*
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* If on run queue move to new run queue, and
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* quit.
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*/
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if (p->p_stat == SRUN) {
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MPASS(p->p_blocked == NULL);
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remrunqueue(p);
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setrunqueue(p);
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return;
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}
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/*
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* If we aren't blocked on a mutex, we should be.
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*/
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KASSERT(p->p_stat == SMTX, (
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"process %d(%s):%d holds %s but isn't blocked on a mutex\n",
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p->p_pid, p->p_comm, p->p_stat,
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m->mtx_description));
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/*
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* Pick up the mutex that p is blocked on.
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*/
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m = p->p_blocked;
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MPASS(m != NULL);
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/*
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* Check if the proc needs to be moved up on
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* the blocked chain
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*/
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if (p == TAILQ_FIRST(&m->mtx_blocked)) {
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continue;
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}
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p1 = TAILQ_PREV(p, procqueue, p_procq);
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if (p1->p_pri.pri_level <= pri) {
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continue;
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}
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/*
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* Remove proc from blocked chain and determine where
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* it should be moved up to. Since we know that p1 has
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* a lower priority than p, we know that at least one
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* process in the chain has a lower priority and that
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* p1 will thus not be NULL after the loop.
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*/
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TAILQ_REMOVE(&m->mtx_blocked, p, p_procq);
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TAILQ_FOREACH(p1, &m->mtx_blocked, p_procq) {
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MPASS(p1->p_magic == P_MAGIC);
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if (p1->p_pri.pri_level > pri)
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break;
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}
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MPASS(p1 != NULL);
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TAILQ_INSERT_BEFORE(p1, p, p_procq);
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CTR4(KTR_LOCK,
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"propagate_priority: p %p moved before %p on [%p] %s",
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p, p1, m, m->mtx_description);
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}
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}
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/*
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* The important part of mtx_trylock{,_flags}()
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* Tries to acquire lock `m.' We do NOT handle recursion here; we assume that
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* if we're called, it's because we know we don't already own this lock.
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*/
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int
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_mtx_trylock(struct mtx *m, int opts, const char *file, int line)
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{
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int rval;
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MPASS(curproc != NULL);
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/*
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* _mtx_trylock does not accept MTX_NOSWITCH option.
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*/
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KASSERT((opts & MTX_NOSWITCH) == 0,
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("mtx_trylock() called with invalid option flag(s) %d", opts));
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rval = _obtain_lock(m, curproc);
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#ifdef WITNESS
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if (rval && m->mtx_witness != NULL) {
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/*
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* We do not handle recursion in _mtx_trylock; see the
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* note at the top of the routine.
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*/
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KASSERT(!mtx_recursed(m),
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("mtx_trylock() called on a recursed mutex"));
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witness_try_enter(m, (opts | m->mtx_flags), file, line);
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}
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#endif /* WITNESS */
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if ((opts & MTX_QUIET) == 0)
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CTR5(KTR_LOCK, "TRY_ENTER %s [%p] result=%d at %s:%d",
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m->mtx_description, m, rval, file, line);
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return rval;
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}
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/*
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* _mtx_lock_sleep: the tougher part of acquiring an MTX_DEF lock.
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*
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* We call this if the lock is either contested (i.e. we need to go to
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* sleep waiting for it), or if we need to recurse on it.
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*/
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void
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_mtx_lock_sleep(struct mtx *m, int opts, const char *file, int line)
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{
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struct proc *p = curproc;
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if ((m->mtx_lock & MTX_FLAGMASK) == (uintptr_t)p) {
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m->mtx_recurse++;
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atomic_set_ptr(&m->mtx_lock, MTX_RECURSED);
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if ((opts & MTX_QUIET) == 0)
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CTR1(KTR_LOCK, "_mtx_lock_sleep: %p recursing", m);
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return;
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}
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if ((opts & MTX_QUIET) == 0)
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CTR3(KTR_LOCK, "_mtx_lock_sleep: %p contested (lock=%p) [%p]",
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m, (void *)m->mtx_lock, (void *)RETIP(m));
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/*
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* Save our priority. Even though p_nativepri is protected by
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* sched_lock, we don't obtain it here as it can be expensive.
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* Since this is the only place p_nativepri is set, and since two
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* CPUs will not be executing the same process concurrently, we know
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* that no other CPU is going to be messing with this. Also,
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* p_nativepri is only read when we are blocked on a mutex, so that
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* can't be happening right now either.
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*/
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p->p_pri.pri_native = p->p_pri.pri_level;
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while (!_obtain_lock(m, p)) {
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uintptr_t v;
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struct proc *p1;
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mtx_lock_spin(&sched_lock);
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/*
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* Check if the lock has been released while spinning for
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* the sched_lock.
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*/
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if ((v = m->mtx_lock) == MTX_UNOWNED) {
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mtx_unlock_spin(&sched_lock);
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continue;
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}
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/*
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* The mutex was marked contested on release. This means that
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* there are processes blocked on it.
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*/
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if (v == MTX_CONTESTED) {
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p1 = TAILQ_FIRST(&m->mtx_blocked);
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MPASS(p1 != NULL);
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m->mtx_lock = (uintptr_t)p | MTX_CONTESTED;
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if (p1->p_pri.pri_level < p->p_pri.pri_level)
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SET_PRIO(p, p1->p_pri.pri_level);
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mtx_unlock_spin(&sched_lock);
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return;
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}
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/*
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* If the mutex isn't already contested and a failure occurs
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* setting the contested bit, the mutex was either released
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* or the state of the MTX_RECURSED bit changed.
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*/
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if ((v & MTX_CONTESTED) == 0 &&
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!atomic_cmpset_ptr(&m->mtx_lock, (void *)v,
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(void *)(v | MTX_CONTESTED))) {
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mtx_unlock_spin(&sched_lock);
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continue;
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}
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/*
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* We deffinately must sleep for this lock.
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*/
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mtx_assert(m, MA_NOTOWNED);
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#ifdef notyet
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/*
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* If we're borrowing an interrupted thread's VM context, we
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* must clean up before going to sleep.
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*/
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if (p->p_flag & (P_ITHD | P_SITHD)) {
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ithd_t *it = (ithd_t *)p;
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if (it->it_interrupted) {
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if ((opts & MTX_QUIET) == 0)
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CTR2(KTR_LOCK,
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"_mtx_lock_sleep: 0x%x interrupted 0x%x",
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it, it->it_interrupted);
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intr_thd_fixup(it);
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}
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}
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#endif
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/*
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* Put us on the list of threads blocked on this mutex.
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*/
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if (TAILQ_EMPTY(&m->mtx_blocked)) {
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p1 = (struct proc *)(m->mtx_lock & MTX_FLAGMASK);
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LIST_INSERT_HEAD(&p1->p_contested, m, mtx_contested);
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TAILQ_INSERT_TAIL(&m->mtx_blocked, p, p_procq);
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} else {
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TAILQ_FOREACH(p1, &m->mtx_blocked, p_procq)
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if (p1->p_pri.pri_level > p->p_pri.pri_level)
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break;
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if (p1)
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TAILQ_INSERT_BEFORE(p1, p, p_procq);
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else
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TAILQ_INSERT_TAIL(&m->mtx_blocked, p, p_procq);
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}
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/*
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* Save who we're blocked on.
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*/
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p->p_blocked = m;
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p->p_mtxname = m->mtx_description;
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p->p_stat = SMTX;
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propagate_priority(p);
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if ((opts & MTX_QUIET) == 0)
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CTR3(KTR_LOCK,
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"_mtx_lock_sleep: p %p blocked on [%p] %s", p, m,
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m->mtx_description);
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mi_switch();
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if ((opts & MTX_QUIET) == 0)
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CTR3(KTR_LOCK,
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"_mtx_lock_sleep: p %p free from blocked on [%p] %s",
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p, m, m->mtx_description);
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mtx_unlock_spin(&sched_lock);
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}
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return;
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}
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/*
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* _mtx_lock_spin: the tougher part of acquiring an MTX_SPIN lock.
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*
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* This is only called if we need to actually spin for the lock. Recursion
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* is handled inline.
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*/
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void
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_mtx_lock_spin(struct mtx *m, int opts, u_int mtx_intr, const char *file,
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int line)
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{
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int i = 0;
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if ((opts & MTX_QUIET) == 0)
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CTR1(KTR_LOCK, "_mtx_lock_spin: %p spinning", m);
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for (;;) {
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if (_obtain_lock(m, curproc))
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break;
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while (m->mtx_lock != MTX_UNOWNED) {
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if (i++ < 1000000)
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continue;
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if (i++ < 6000000)
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DELAY(1);
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#ifdef DDB
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else if (!db_active)
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#else
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else
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#endif
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panic("spin lock %s held by %p for > 5 seconds",
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m->mtx_description, (void *)m->mtx_lock);
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}
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}
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m->mtx_saveintr = mtx_intr;
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if ((opts & MTX_QUIET) == 0)
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CTR1(KTR_LOCK, "_mtx_lock_spin: %p spin done", m);
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return;
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}
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|
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/*
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* _mtx_unlock_sleep: the tougher part of releasing an MTX_DEF lock.
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*
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* We are only called here if the lock is recursed or contested (i.e. we
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* need to wake up a blocked thread).
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*/
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void
|
|
_mtx_unlock_sleep(struct mtx *m, int opts, const char *file, int line)
|
|
{
|
|
struct proc *p, *p1;
|
|
struct mtx *m1;
|
|
int pri;
|
|
|
|
p = curproc;
|
|
MPASS4(mtx_owned(m), "mtx_owned(mpp)", file, line);
|
|
|
|
if (mtx_recursed(m)) {
|
|
if (--(m->mtx_recurse) == 0)
|
|
atomic_clear_ptr(&m->mtx_lock, MTX_RECURSED);
|
|
if ((opts & MTX_QUIET) == 0)
|
|
CTR1(KTR_LOCK, "_mtx_unlock_sleep: %p unrecurse", m);
|
|
return;
|
|
}
|
|
|
|
mtx_lock_spin(&sched_lock);
|
|
if ((opts & MTX_QUIET) == 0)
|
|
CTR1(KTR_LOCK, "_mtx_unlock_sleep: %p contested", m);
|
|
|
|
p1 = TAILQ_FIRST(&m->mtx_blocked);
|
|
MPASS(p->p_magic == P_MAGIC);
|
|
MPASS(p1->p_magic == P_MAGIC);
|
|
|
|
TAILQ_REMOVE(&m->mtx_blocked, p1, p_procq);
|
|
|
|
if (TAILQ_EMPTY(&m->mtx_blocked)) {
|
|
LIST_REMOVE(m, mtx_contested);
|
|
_release_lock_quick(m);
|
|
if ((opts & MTX_QUIET) == 0)
|
|
CTR1(KTR_LOCK, "_mtx_unlock_sleep: %p not held", m);
|
|
} else
|
|
atomic_store_rel_ptr(&m->mtx_lock, (void *)MTX_CONTESTED);
|
|
|
|
pri = PRI_MAX;
|
|
LIST_FOREACH(m1, &p->p_contested, mtx_contested) {
|
|
int cp = TAILQ_FIRST(&m1->mtx_blocked)->p_pri.pri_level;
|
|
if (cp < pri)
|
|
pri = cp;
|
|
}
|
|
|
|
if (pri > p->p_pri.pri_native)
|
|
pri = p->p_pri.pri_native;
|
|
SET_PRIO(p, pri);
|
|
|
|
if ((opts & MTX_QUIET) == 0)
|
|
CTR2(KTR_LOCK, "_mtx_unlock_sleep: %p contested setrunqueue %p",
|
|
m, p1);
|
|
|
|
p1->p_blocked = NULL;
|
|
p1->p_mtxname = NULL;
|
|
p1->p_stat = SRUN;
|
|
setrunqueue(p1);
|
|
|
|
if ((opts & MTX_NOSWITCH) == 0 && p1->p_pri.pri_level < pri) {
|
|
#ifdef notyet
|
|
if (p->p_flag & (P_ITHD | P_SITHD)) {
|
|
ithd_t *it = (ithd_t *)p;
|
|
|
|
if (it->it_interrupted) {
|
|
if ((opts & MTX_QUIET) == 0)
|
|
CTR2(KTR_LOCK,
|
|
"_mtx_unlock_sleep: 0x%x interrupted 0x%x",
|
|
it, it->it_interrupted);
|
|
intr_thd_fixup(it);
|
|
}
|
|
}
|
|
#endif
|
|
setrunqueue(p);
|
|
if ((opts & MTX_QUIET) == 0)
|
|
CTR2(KTR_LOCK,
|
|
"_mtx_unlock_sleep: %p switching out lock=%p", m,
|
|
(void *)m->mtx_lock);
|
|
|
|
mi_switch();
|
|
if ((opts & MTX_QUIET) == 0)
|
|
CTR2(KTR_LOCK, "_mtx_unlock_sleep: %p resuming lock=%p",
|
|
m, (void *)m->mtx_lock);
|
|
}
|
|
|
|
mtx_unlock_spin(&sched_lock);
|
|
|
|
return;
|
|
}
|
|
|
|
/*
|
|
* All the unlocking of MTX_SPIN locks is done inline.
|
|
* See the _rel_spin_lock() macro for the details.
|
|
*/
|
|
|
|
/*
|
|
* The INVARIANTS-enabled mtx_assert()
|
|
*/
|
|
#ifdef INVARIANTS
|
|
void
|
|
_mtx_assert(struct mtx *m, int what, const char *file, int line)
|
|
{
|
|
switch ((what)) {
|
|
case MA_OWNED:
|
|
case MA_OWNED | MA_RECURSED:
|
|
case MA_OWNED | MA_NOTRECURSED:
|
|
if (!mtx_owned((m)))
|
|
panic("mutex %s not owned at %s:%d",
|
|
(m)->mtx_description, file, line);
|
|
if (mtx_recursed((m))) {
|
|
if (((what) & MA_NOTRECURSED) != 0)
|
|
panic("mutex %s recursed at %s:%d",
|
|
(m)->mtx_description, file, line);
|
|
} else if (((what) & MA_RECURSED) != 0) {
|
|
panic("mutex %s unrecursed at %s:%d",
|
|
(m)->mtx_description, file, line);
|
|
}
|
|
break;
|
|
case MA_NOTOWNED:
|
|
if (mtx_owned((m)))
|
|
panic("mutex %s owned at %s:%d",
|
|
(m)->mtx_description, file, line);
|
|
break;
|
|
default:
|
|
panic("unknown mtx_assert at %s:%d", file, line);
|
|
}
|
|
}
|
|
#endif
|
|
|
|
/*
|
|
* The MUTEX_DEBUG-enabled mtx_validate()
|
|
*/
|
|
#define MV_DESTROY 0 /* validate before destory */
|
|
#define MV_INIT 1 /* validate before init */
|
|
|
|
#ifdef MUTEX_DEBUG
|
|
|
|
int mtx_validate __P((struct mtx *, int));
|
|
|
|
int
|
|
mtx_validate(struct mtx *m, int when)
|
|
{
|
|
struct mtx *mp;
|
|
int i;
|
|
int retval = 0;
|
|
|
|
#ifdef WITNESS
|
|
if (witness_cold)
|
|
return 0;
|
|
#endif
|
|
if (m == &all_mtx || cold)
|
|
return 0;
|
|
|
|
mtx_lock(&all_mtx);
|
|
/*
|
|
* XXX - When kernacc() is fixed on the alpha to handle K0_SEG memory properly
|
|
* we can re-enable the kernacc() checks.
|
|
*/
|
|
#ifndef __alpha__
|
|
MPASS(kernacc((caddr_t)all_mtx.mtx_next, sizeof(uintptr_t),
|
|
VM_PROT_READ) == 1);
|
|
#endif
|
|
MPASS(all_mtx.mtx_next->mtx_prev == &all_mtx);
|
|
for (i = 0, mp = all_mtx.mtx_next; mp != &all_mtx; mp = mp->mtx_next) {
|
|
#ifndef __alpha__
|
|
if (kernacc((caddr_t)mp->mtx_next, sizeof(uintptr_t),
|
|
VM_PROT_READ) != 1) {
|
|
panic("mtx_validate: mp=%p mp->mtx_next=%p",
|
|
mp, mp->mtx_next);
|
|
}
|
|
#endif
|
|
i++;
|
|
if (i > mtx_cur_cnt) {
|
|
panic("mtx_validate: too many in chain, known=%d\n",
|
|
mtx_cur_cnt);
|
|
}
|
|
}
|
|
MPASS(i == mtx_cur_cnt);
|
|
switch (when) {
|
|
case MV_DESTROY:
|
|
for (mp = all_mtx.mtx_next; mp != &all_mtx; mp = mp->mtx_next)
|
|
if (mp == m)
|
|
break;
|
|
MPASS(mp == m);
|
|
break;
|
|
case MV_INIT:
|
|
for (mp = all_mtx.mtx_next; mp != &all_mtx; mp = mp->mtx_next)
|
|
if (mp == m) {
|
|
/*
|
|
* Not good. This mutex already exists.
|
|
*/
|
|
printf("re-initing existing mutex %s\n",
|
|
m->mtx_description);
|
|
MPASS(m->mtx_lock == MTX_UNOWNED);
|
|
retval = 1;
|
|
}
|
|
}
|
|
mtx_unlock(&all_mtx);
|
|
return (retval);
|
|
}
|
|
#endif
|
|
|
|
/*
|
|
* Mutex initialization routine; initialize lock `m' of type contained in
|
|
* `opts' with options contained in `opts' and description `description.'
|
|
* Place on "all_mtx" queue.
|
|
*/
|
|
void
|
|
mtx_init(struct mtx *m, const char *description, int opts)
|
|
{
|
|
|
|
if ((opts & MTX_QUIET) == 0)
|
|
CTR2(KTR_LOCK, "mtx_init %p (%s)", m, description);
|
|
|
|
#ifdef MUTEX_DEBUG
|
|
/* Diagnostic and error correction */
|
|
if (mtx_validate(m, MV_INIT))
|
|
return;
|
|
#endif
|
|
|
|
bzero((void *)m, sizeof *m);
|
|
TAILQ_INIT(&m->mtx_blocked);
|
|
|
|
#ifdef WITNESS
|
|
if (!witness_cold) {
|
|
m->mtx_debug = malloc(sizeof(struct mtx_debug),
|
|
M_WITNESS, M_NOWAIT | M_ZERO);
|
|
MPASS(m->mtx_debug != NULL);
|
|
}
|
|
#endif
|
|
|
|
m->mtx_description = description;
|
|
m->mtx_flags = opts;
|
|
m->mtx_lock = MTX_UNOWNED;
|
|
|
|
/* Put on all mutex queue */
|
|
mtx_lock(&all_mtx);
|
|
m->mtx_next = &all_mtx;
|
|
m->mtx_prev = all_mtx.mtx_prev;
|
|
m->mtx_prev->mtx_next = m;
|
|
all_mtx.mtx_prev = m;
|
|
if (++mtx_cur_cnt > mtx_max_cnt)
|
|
mtx_max_cnt = mtx_cur_cnt;
|
|
mtx_unlock(&all_mtx);
|
|
|
|
#ifdef WITNESS
|
|
if (!witness_cold)
|
|
witness_init(m, opts);
|
|
#endif
|
|
}
|
|
|
|
/*
|
|
* Remove lock `m' from all_mtx queue.
|
|
*/
|
|
void
|
|
mtx_destroy(struct mtx *m)
|
|
{
|
|
|
|
#ifdef WITNESS
|
|
KASSERT(!witness_cold, ("%s: Cannot destroy while still cold\n",
|
|
__FUNCTION__));
|
|
#endif
|
|
|
|
CTR2(KTR_LOCK, "mtx_destroy %p (%s)", m, m->mtx_description);
|
|
|
|
#ifdef MUTEX_DEBUG
|
|
if (m->mtx_next == NULL)
|
|
panic("mtx_destroy: %p (%s) already destroyed",
|
|
m, m->mtx_description);
|
|
|
|
if (!mtx_owned(m)) {
|
|
MPASS(m->mtx_lock == MTX_UNOWNED);
|
|
} else {
|
|
MPASS((m->mtx_lock & (MTX_RECURSED|MTX_CONTESTED)) == 0);
|
|
}
|
|
|
|
/* diagnostic */
|
|
mtx_validate(m, MV_DESTROY);
|
|
#endif
|
|
|
|
#ifdef WITNESS
|
|
if (m->mtx_witness)
|
|
witness_destroy(m);
|
|
#endif /* WITNESS */
|
|
|
|
/* Remove from the all mutex queue */
|
|
mtx_lock(&all_mtx);
|
|
m->mtx_next->mtx_prev = m->mtx_prev;
|
|
m->mtx_prev->mtx_next = m->mtx_next;
|
|
|
|
#ifdef MUTEX_DEBUG
|
|
m->mtx_next = m->mtx_prev = NULL;
|
|
#endif
|
|
|
|
#ifdef WITNESS
|
|
free(m->mtx_debug, M_WITNESS);
|
|
m->mtx_debug = NULL;
|
|
#endif
|
|
|
|
mtx_cur_cnt--;
|
|
mtx_unlock(&all_mtx);
|
|
}
|
|
|
|
|
|
/*
|
|
* The WITNESS-enabled diagnostic code.
|
|
*/
|
|
#ifdef WITNESS
|
|
static void
|
|
witness_fixup(void *dummy __unused)
|
|
{
|
|
struct mtx *mp;
|
|
|
|
/*
|
|
* 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);
|
|
|
|
mtx_lock(&all_mtx);
|
|
|
|
/* Iterate through all mutexes and finish up mutex initialization. */
|
|
for (mp = all_mtx.mtx_next; mp != &all_mtx; mp = mp->mtx_next) {
|
|
|
|
mp->mtx_debug = malloc(sizeof(struct mtx_debug),
|
|
M_WITNESS, M_NOWAIT | M_ZERO);
|
|
MPASS(mp->mtx_debug != NULL);
|
|
|
|
witness_init(mp, mp->mtx_flags);
|
|
}
|
|
mtx_unlock(&all_mtx);
|
|
|
|
/* Mark the witness code as being ready for use. */
|
|
atomic_store_rel_int(&witness_cold, 0);
|
|
|
|
mtx_lock(&Giant);
|
|
}
|
|
SYSINIT(wtnsfxup, SI_SUB_MUTEX, SI_ORDER_FIRST, witness_fixup, NULL)
|
|
|
|
#define WITNESS_COUNT 200
|
|
#define WITNESS_NCHILDREN 2
|
|
|
|
int witness_watch = 1;
|
|
|
|
struct witness {
|
|
struct witness *w_next;
|
|
const char *w_description;
|
|
const char *w_file;
|
|
int w_line;
|
|
struct witness *w_morechildren;
|
|
u_char w_childcnt;
|
|
u_char w_Giant_squawked:1;
|
|
u_char w_other_squawked:1;
|
|
u_char w_same_squawked:1;
|
|
u_char w_spin:1; /* MTX_SPIN type mutex. */
|
|
u_int w_level;
|
|
struct witness *w_children[WITNESS_NCHILDREN];
|
|
};
|
|
|
|
struct witness_blessed {
|
|
char *b_lock1;
|
|
char *b_lock2;
|
|
};
|
|
|
|
#ifdef DDB
|
|
/*
|
|
* When DDB is enabled and witness_ddb is set to 1, it will cause the system to
|
|
* drop into kdebug() when:
|
|
* - a lock heirarchy violation occurs
|
|
* - locks are held when going to sleep.
|
|
*/
|
|
int witness_ddb;
|
|
#ifdef WITNESS_DDB
|
|
TUNABLE_INT_DECL("debug.witness_ddb", 1, witness_ddb);
|
|
#else
|
|
TUNABLE_INT_DECL("debug.witness_ddb", 0, witness_ddb);
|
|
#endif
|
|
SYSCTL_INT(_debug, OID_AUTO, witness_ddb, CTLFLAG_RW, &witness_ddb, 0, "");
|
|
#endif /* DDB */
|
|
|
|
int witness_skipspin;
|
|
#ifdef WITNESS_SKIPSPIN
|
|
TUNABLE_INT_DECL("debug.witness_skipspin", 1, witness_skipspin);
|
|
#else
|
|
TUNABLE_INT_DECL("debug.witness_skipspin", 0, witness_skipspin);
|
|
#endif
|
|
SYSCTL_INT(_debug, OID_AUTO, witness_skipspin, CTLFLAG_RD, &witness_skipspin, 0,
|
|
"");
|
|
|
|
/*
|
|
* Witness-enabled globals
|
|
*/
|
|
static struct mtx w_mtx;
|
|
static struct witness *w_free;
|
|
static struct witness *w_all;
|
|
static int w_inited;
|
|
static int witness_dead; /* fatal error, probably no memory */
|
|
|
|
static struct witness w_data[WITNESS_COUNT];
|
|
|
|
/*
|
|
* Internal witness routine prototypes
|
|
*/
|
|
static struct witness *enroll(const char *description, int flag);
|
|
static int itismychild(struct witness *parent, struct witness *child);
|
|
static void removechild(struct witness *parent, struct witness *child);
|
|
static int isitmychild(struct witness *parent, struct witness *child);
|
|
static int isitmydescendant(struct witness *parent, struct witness *child);
|
|
static int dup_ok(struct witness *);
|
|
static int blessed(struct witness *, struct witness *);
|
|
static void
|
|
witness_displaydescendants(void(*)(const char *fmt, ...), struct witness *);
|
|
static void witness_leveldescendents(struct witness *parent, int level);
|
|
static void witness_levelall(void);
|
|
static struct witness * witness_get(void);
|
|
static void witness_free(struct witness *m);
|
|
|
|
static char *ignore_list[] = {
|
|
"witness lock",
|
|
NULL
|
|
};
|
|
|
|
static char *spin_order_list[] = {
|
|
#if defined(__i386__) && defined (SMP)
|
|
"com",
|
|
#endif
|
|
"sio",
|
|
#ifdef __i386__
|
|
"cy",
|
|
#endif
|
|
"sched lock",
|
|
#ifdef __i386__
|
|
"clk",
|
|
#endif
|
|
"callout",
|
|
/*
|
|
* leaf locks
|
|
*/
|
|
"ithread table lock",
|
|
"ithread list lock",
|
|
#ifdef SMP
|
|
#ifdef __i386__
|
|
"ap boot",
|
|
"imen",
|
|
#endif
|
|
"smp rendezvous",
|
|
#endif
|
|
NULL
|
|
};
|
|
|
|
static char *order_list[] = {
|
|
"Giant", "proctree", "allproc", "process lock", "uidinfo hash",
|
|
"uidinfo struct", NULL,
|
|
NULL
|
|
};
|
|
|
|
static char *dup_list[] = {
|
|
NULL
|
|
};
|
|
|
|
static char *sleep_list[] = {
|
|
"Giant",
|
|
NULL
|
|
};
|
|
|
|
/*
|
|
* 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);
|
|
|
|
static void
|
|
witness_init(struct mtx *m, int flag)
|
|
{
|
|
m->mtx_witness = enroll(m->mtx_description, flag);
|
|
}
|
|
|
|
static void
|
|
witness_destroy(struct mtx *m)
|
|
{
|
|
struct mtx *m1;
|
|
struct proc *p;
|
|
p = curproc;
|
|
LIST_FOREACH(m1, &p->p_heldmtx, mtx_held) {
|
|
if (m1 == m) {
|
|
LIST_REMOVE(m, mtx_held);
|
|
break;
|
|
}
|
|
}
|
|
return;
|
|
|
|
}
|
|
|
|
static void
|
|
witness_display(void(*prnt)(const char *fmt, ...))
|
|
{
|
|
struct witness *w, *w1;
|
|
int level, found;
|
|
|
|
KASSERT(!witness_cold, ("%s: witness_cold\n", __FUNCTION__));
|
|
witness_levelall();
|
|
|
|
/*
|
|
* First, handle sleep mutexes which have been acquired at least
|
|
* once.
|
|
*/
|
|
prnt("Sleep mutexes:\n");
|
|
for (w = w_all; w; w = w->w_next) {
|
|
if (w->w_file == NULL || w->w_spin)
|
|
continue;
|
|
for (w1 = w_all; w1; w1 = w1->w_next) {
|
|
if (isitmychild(w1, w))
|
|
break;
|
|
}
|
|
if (w1 != NULL)
|
|
continue;
|
|
/*
|
|
* This lock has no anscestors, display its descendants.
|
|
*/
|
|
witness_displaydescendants(prnt, w);
|
|
}
|
|
|
|
/*
|
|
* Now do spin mutexes which have been acquired at least once.
|
|
*/
|
|
prnt("\nSpin mutexes:\n");
|
|
level = 0;
|
|
while (level < sizeof(spin_order_list) / sizeof(char *)) {
|
|
found = 0;
|
|
for (w = w_all; w; w = w->w_next) {
|
|
if (w->w_file == NULL || !w->w_spin)
|
|
continue;
|
|
if (w->w_level == 1 << level) {
|
|
witness_displaydescendants(prnt, w);
|
|
level++;
|
|
found = 1;
|
|
}
|
|
}
|
|
if (found == 0)
|
|
level++;
|
|
}
|
|
|
|
/*
|
|
* Finally, any mutexes which have not been acquired yet.
|
|
*/
|
|
prnt("\nMutexes which were never acquired:\n");
|
|
for (w = w_all; w; w = w->w_next) {
|
|
if (w->w_file != NULL)
|
|
continue;
|
|
prnt("%s\n", w->w_description);
|
|
}
|
|
}
|
|
|
|
void
|
|
witness_enter(struct mtx *m, int flags, const char *file, int line)
|
|
{
|
|
struct witness *w, *w1;
|
|
struct mtx *m1;
|
|
struct proc *p;
|
|
int i;
|
|
#ifdef DDB
|
|
int go_into_ddb = 0;
|
|
#endif /* DDB */
|
|
|
|
if (witness_cold || m->mtx_witness == NULL || panicstr)
|
|
return;
|
|
w = m->mtx_witness;
|
|
p = curproc;
|
|
|
|
if (flags & MTX_SPIN) {
|
|
if ((m->mtx_flags & MTX_SPIN) == 0)
|
|
panic("mutex_enter: MTX_SPIN on MTX_DEF mutex %s @"
|
|
" %s:%d", m->mtx_description, file, line);
|
|
if (mtx_recursed(m)) {
|
|
if ((m->mtx_flags & MTX_RECURSE) == 0)
|
|
panic("mutex_enter: recursion on non-recursive"
|
|
" mutex %s @ %s:%d", m->mtx_description,
|
|
file, line);
|
|
return;
|
|
}
|
|
mtx_lock_spin_flags(&w_mtx, MTX_QUIET);
|
|
i = PCPU_GET(witness_spin_check);
|
|
if (i != 0 && w->w_level < i) {
|
|
mtx_unlock_spin_flags(&w_mtx, MTX_QUIET);
|
|
panic("mutex_enter(%s:%x, MTX_SPIN) out of order @"
|
|
" %s:%d already holding %s:%x",
|
|
m->mtx_description, w->w_level, file, line,
|
|
spin_order_list[ffs(i)-1], i);
|
|
}
|
|
PCPU_SET(witness_spin_check, i | w->w_level);
|
|
mtx_unlock_spin_flags(&w_mtx, MTX_QUIET);
|
|
w->w_file = file;
|
|
w->w_line = line;
|
|
m->mtx_line = line;
|
|
m->mtx_file = file;
|
|
return;
|
|
}
|
|
if ((m->mtx_flags & MTX_SPIN) != 0)
|
|
panic("mutex_enter: MTX_DEF on MTX_SPIN mutex %s @ %s:%d",
|
|
m->mtx_description, file, line);
|
|
|
|
if (mtx_recursed(m)) {
|
|
if ((m->mtx_flags & MTX_RECURSE) == 0)
|
|
panic("mutex_enter: recursion on non-recursive"
|
|
" mutex %s @ %s:%d", m->mtx_description,
|
|
file, line);
|
|
return;
|
|
}
|
|
if (witness_dead)
|
|
goto out;
|
|
if (cold)
|
|
goto out;
|
|
|
|
if (!mtx_legal2block())
|
|
panic("blockable mtx_lock() of %s when not legal @ %s:%d",
|
|
m->mtx_description, file, line);
|
|
/*
|
|
* Is this the first mutex acquired
|
|
*/
|
|
if ((m1 = LIST_FIRST(&p->p_heldmtx)) == NULL)
|
|
goto out;
|
|
|
|
if ((w1 = m1->mtx_witness) == w) {
|
|
if (w->w_same_squawked || dup_ok(w))
|
|
goto out;
|
|
w->w_same_squawked = 1;
|
|
printf("acquring duplicate lock of same type: \"%s\"\n",
|
|
m->mtx_description);
|
|
printf(" 1st @ %s:%d\n", w->w_file, w->w_line);
|
|
printf(" 2nd @ %s:%d\n", file, line);
|
|
#ifdef DDB
|
|
go_into_ddb = 1;
|
|
#endif /* DDB */
|
|
goto out;
|
|
}
|
|
MPASS(!mtx_owned(&w_mtx));
|
|
mtx_lock_spin_flags(&w_mtx, MTX_QUIET);
|
|
/*
|
|
* If we have a known higher number just say ok
|
|
*/
|
|
if (witness_watch > 1 && w->w_level > w1->w_level) {
|
|
mtx_unlock_spin_flags(&w_mtx, MTX_QUIET);
|
|
goto out;
|
|
}
|
|
if (isitmydescendant(m1->mtx_witness, w)) {
|
|
mtx_unlock_spin_flags(&w_mtx, MTX_QUIET);
|
|
goto out;
|
|
}
|
|
for (i = 0; m1 != NULL; m1 = LIST_NEXT(m1, mtx_held), i++) {
|
|
|
|
MPASS(i < 200);
|
|
w1 = m1->mtx_witness;
|
|
if (isitmydescendant(w, w1)) {
|
|
mtx_unlock_spin_flags(&w_mtx, MTX_QUIET);
|
|
if (blessed(w, w1))
|
|
goto out;
|
|
if (m1 == &Giant) {
|
|
if (w1->w_Giant_squawked)
|
|
goto out;
|
|
else
|
|
w1->w_Giant_squawked = 1;
|
|
} else {
|
|
if (w1->w_other_squawked)
|
|
goto out;
|
|
else
|
|
w1->w_other_squawked = 1;
|
|
}
|
|
printf("lock order reversal\n");
|
|
printf(" 1st %s last acquired @ %s:%d\n",
|
|
w->w_description, w->w_file, w->w_line);
|
|
printf(" 2nd %p %s @ %s:%d\n",
|
|
m1, w1->w_description, w1->w_file, w1->w_line);
|
|
printf(" 3rd %p %s @ %s:%d\n",
|
|
m, w->w_description, file, line);
|
|
#ifdef DDB
|
|
go_into_ddb = 1;
|
|
#endif /* DDB */
|
|
goto out;
|
|
}
|
|
}
|
|
m1 = LIST_FIRST(&p->p_heldmtx);
|
|
if (!itismychild(m1->mtx_witness, w))
|
|
mtx_unlock_spin_flags(&w_mtx, MTX_QUIET);
|
|
|
|
out:
|
|
#ifdef DDB
|
|
if (witness_ddb && go_into_ddb)
|
|
Debugger("witness_enter");
|
|
#endif /* DDB */
|
|
w->w_file = file;
|
|
w->w_line = line;
|
|
m->mtx_line = line;
|
|
m->mtx_file = file;
|
|
|
|
/*
|
|
* If this pays off it likely means that a mutex being witnessed
|
|
* is acquired in hardclock. Put it in the ignore list. It is
|
|
* likely not the mutex this assert fails on.
|
|
*/
|
|
MPASS(m->mtx_held.le_prev == NULL);
|
|
LIST_INSERT_HEAD(&p->p_heldmtx, (struct mtx*)m, mtx_held);
|
|
}
|
|
|
|
void
|
|
witness_try_enter(struct mtx *m, int flags, const char *file, int line)
|
|
{
|
|
struct proc *p;
|
|
struct witness *w = m->mtx_witness;
|
|
|
|
if (witness_cold)
|
|
return;
|
|
if (panicstr)
|
|
return;
|
|
if (flags & MTX_SPIN) {
|
|
if ((m->mtx_flags & MTX_SPIN) == 0)
|
|
panic("mutex_try_enter: "
|
|
"MTX_SPIN on MTX_DEF mutex %s @ %s:%d",
|
|
m->mtx_description, file, line);
|
|
if (mtx_recursed(m)) {
|
|
if ((m->mtx_flags & MTX_RECURSE) == 0)
|
|
panic("mutex_try_enter: recursion on"
|
|
" non-recursive mutex %s @ %s:%d",
|
|
m->mtx_description, file, line);
|
|
return;
|
|
}
|
|
mtx_lock_spin_flags(&w_mtx, MTX_QUIET);
|
|
PCPU_SET(witness_spin_check,
|
|
PCPU_GET(witness_spin_check) | w->w_level);
|
|
mtx_unlock_spin_flags(&w_mtx, MTX_QUIET);
|
|
w->w_file = file;
|
|
w->w_line = line;
|
|
m->mtx_line = line;
|
|
m->mtx_file = file;
|
|
return;
|
|
}
|
|
|
|
if ((m->mtx_flags & MTX_SPIN) != 0)
|
|
panic("mutex_try_enter: MTX_DEF on MTX_SPIN mutex %s @ %s:%d",
|
|
m->mtx_description, file, line);
|
|
|
|
if (mtx_recursed(m)) {
|
|
if ((m->mtx_flags & MTX_RECURSE) == 0)
|
|
panic("mutex_try_enter: recursion on non-recursive"
|
|
" mutex %s @ %s:%d", m->mtx_description, file,
|
|
line);
|
|
return;
|
|
}
|
|
w->w_file = file;
|
|
w->w_line = line;
|
|
m->mtx_line = line;
|
|
m->mtx_file = file;
|
|
p = curproc;
|
|
MPASS(m->mtx_held.le_prev == NULL);
|
|
LIST_INSERT_HEAD(&p->p_heldmtx, (struct mtx*)m, mtx_held);
|
|
}
|
|
|
|
void
|
|
witness_exit(struct mtx *m, int flags, const char *file, int line)
|
|
{
|
|
struct witness *w;
|
|
|
|
if (witness_cold || m->mtx_witness == NULL || panicstr)
|
|
return;
|
|
w = m->mtx_witness;
|
|
|
|
if (flags & MTX_SPIN) {
|
|
if ((m->mtx_flags & MTX_SPIN) == 0)
|
|
panic("mutex_exit: MTX_SPIN on MTX_DEF mutex %s @"
|
|
" %s:%d", m->mtx_description, file, line);
|
|
if (mtx_recursed(m)) {
|
|
if ((m->mtx_flags & MTX_RECURSE) == 0)
|
|
panic("mutex_exit: recursion on non-recursive"
|
|
" mutex %s @ %s:%d", m->mtx_description,
|
|
file, line);
|
|
return;
|
|
}
|
|
mtx_lock_spin_flags(&w_mtx, MTX_QUIET);
|
|
PCPU_SET(witness_spin_check,
|
|
PCPU_GET(witness_spin_check) & ~w->w_level);
|
|
mtx_unlock_spin_flags(&w_mtx, MTX_QUIET);
|
|
return;
|
|
}
|
|
if ((m->mtx_flags & MTX_SPIN) != 0)
|
|
panic("mutex_exit: MTX_DEF on MTX_SPIN mutex %s @ %s:%d",
|
|
m->mtx_description, file, line);
|
|
|
|
if (mtx_recursed(m)) {
|
|
if ((m->mtx_flags & MTX_RECURSE) == 0)
|
|
panic("mutex_exit: recursion on non-recursive"
|
|
" mutex %s @ %s:%d", m->mtx_description,
|
|
file, line);
|
|
return;
|
|
}
|
|
|
|
if ((flags & MTX_NOSWITCH) == 0 && !mtx_legal2block() && !cold)
|
|
panic("switchable mtx_unlock() of %s when not legal @ %s:%d",
|
|
m->mtx_description, file, line);
|
|
LIST_REMOVE(m, mtx_held);
|
|
m->mtx_held.le_prev = NULL;
|
|
}
|
|
|
|
int
|
|
witness_sleep(int check_only, struct mtx *mtx, const char *file, int line)
|
|
{
|
|
struct mtx *m;
|
|
struct proc *p;
|
|
char **sleep;
|
|
int n = 0;
|
|
|
|
KASSERT(!witness_cold, ("%s: witness_cold\n", __FUNCTION__));
|
|
p = curproc;
|
|
LIST_FOREACH(m, &p->p_heldmtx, mtx_held) {
|
|
if (m == mtx)
|
|
continue;
|
|
for (sleep = sleep_list; *sleep!= NULL; sleep++)
|
|
if (strcmp(m->mtx_description, *sleep) == 0)
|
|
goto next;
|
|
if (n == 0)
|
|
printf("Whee!\n");
|
|
printf("%s:%d: %s with \"%s\" locked from %s:%d\n",
|
|
file, line, check_only ? "could sleep" : "sleeping",
|
|
m->mtx_description,
|
|
m->mtx_witness->w_file, m->mtx_witness->w_line);
|
|
n++;
|
|
next:
|
|
}
|
|
#ifdef DDB
|
|
if (witness_ddb && n)
|
|
Debugger("witness_sleep");
|
|
#endif /* DDB */
|
|
return (n);
|
|
}
|
|
|
|
static struct witness *
|
|
enroll(const char *description, int flag)
|
|
{
|
|
int i;
|
|
struct witness *w, *w1;
|
|
char **ignore;
|
|
char **order;
|
|
|
|
if (!witness_watch)
|
|
return (NULL);
|
|
for (ignore = ignore_list; *ignore != NULL; ignore++)
|
|
if (strcmp(description, *ignore) == 0)
|
|
return (NULL);
|
|
|
|
if (w_inited == 0) {
|
|
mtx_init(&w_mtx, "witness lock", MTX_SPIN);
|
|
for (i = 0; i < WITNESS_COUNT; i++) {
|
|
w = &w_data[i];
|
|
witness_free(w);
|
|
}
|
|
w_inited = 1;
|
|
for (order = order_list; *order != NULL; order++) {
|
|
w = enroll(*order, MTX_DEF);
|
|
w->w_file = "order list";
|
|
for (order++; *order != NULL; order++) {
|
|
w1 = enroll(*order, MTX_DEF);
|
|
w1->w_file = "order list";
|
|
itismychild(w, w1);
|
|
w = w1;
|
|
}
|
|
}
|
|
}
|
|
if ((flag & MTX_SPIN) && witness_skipspin)
|
|
return (NULL);
|
|
mtx_lock_spin_flags(&w_mtx, MTX_QUIET);
|
|
for (w = w_all; w; w = w->w_next) {
|
|
if (strcmp(description, w->w_description) == 0) {
|
|
mtx_unlock_spin_flags(&w_mtx, MTX_QUIET);
|
|
return (w);
|
|
}
|
|
}
|
|
if ((w = witness_get()) == NULL)
|
|
return (NULL);
|
|
w->w_next = w_all;
|
|
w_all = w;
|
|
w->w_description = description;
|
|
mtx_unlock_spin_flags(&w_mtx, MTX_QUIET);
|
|
if (flag & MTX_SPIN) {
|
|
w->w_spin = 1;
|
|
|
|
i = 1;
|
|
for (order = spin_order_list; *order != NULL; order++) {
|
|
if (strcmp(description, *order) == 0)
|
|
break;
|
|
i <<= 1;
|
|
}
|
|
if (*order == NULL)
|
|
panic("spin lock %s not in order list", description);
|
|
w->w_level = i;
|
|
}
|
|
|
|
return (w);
|
|
}
|
|
|
|
static int
|
|
itismychild(struct witness *parent, struct witness *child)
|
|
{
|
|
static int recursed;
|
|
|
|
/*
|
|
* Insert "child" after "parent"
|
|
*/
|
|
while (parent->w_morechildren)
|
|
parent = parent->w_morechildren;
|
|
|
|
if (parent->w_childcnt == WITNESS_NCHILDREN) {
|
|
if ((parent->w_morechildren = witness_get()) == NULL)
|
|
return (1);
|
|
parent = parent->w_morechildren;
|
|
}
|
|
MPASS(child != NULL);
|
|
parent->w_children[parent->w_childcnt++] = child;
|
|
/*
|
|
* now prune whole tree
|
|
*/
|
|
if (recursed)
|
|
return (0);
|
|
recursed = 1;
|
|
for (child = w_all; child != NULL; child = child->w_next) {
|
|
for (parent = w_all; parent != NULL;
|
|
parent = parent->w_next) {
|
|
if (!isitmychild(parent, child))
|
|
continue;
|
|
removechild(parent, child);
|
|
if (isitmydescendant(parent, child))
|
|
continue;
|
|
itismychild(parent, child);
|
|
}
|
|
}
|
|
recursed = 0;
|
|
witness_levelall();
|
|
return (0);
|
|
}
|
|
|
|
static void
|
|
removechild(struct witness *parent, struct witness *child)
|
|
{
|
|
struct witness *w, *w1;
|
|
int i;
|
|
|
|
for (w = parent; w != NULL; w = w->w_morechildren)
|
|
for (i = 0; i < w->w_childcnt; i++)
|
|
if (w->w_children[i] == child)
|
|
goto found;
|
|
return;
|
|
found:
|
|
for (w1 = w; w1->w_morechildren != NULL; w1 = w1->w_morechildren)
|
|
continue;
|
|
w->w_children[i] = w1->w_children[--w1->w_childcnt];
|
|
MPASS(w->w_children[i] != NULL);
|
|
|
|
if (w1->w_childcnt != 0)
|
|
return;
|
|
|
|
if (w1 == parent)
|
|
return;
|
|
for (w = parent; w->w_morechildren != w1; w = w->w_morechildren)
|
|
continue;
|
|
w->w_morechildren = 0;
|
|
witness_free(w1);
|
|
}
|
|
|
|
static int
|
|
isitmychild(struct witness *parent, struct witness *child)
|
|
{
|
|
struct witness *w;
|
|
int i;
|
|
|
|
for (w = parent; w != NULL; w = w->w_morechildren) {
|
|
for (i = 0; i < w->w_childcnt; i++) {
|
|
if (w->w_children[i] == child)
|
|
return (1);
|
|
}
|
|
}
|
|
return (0);
|
|
}
|
|
|
|
static int
|
|
isitmydescendant(struct witness *parent, struct witness *child)
|
|
{
|
|
struct witness *w;
|
|
int i;
|
|
int j;
|
|
|
|
for (j = 0, w = parent; w != NULL; w = w->w_morechildren, j++) {
|
|
MPASS(j < 1000);
|
|
for (i = 0; i < w->w_childcnt; i++) {
|
|
if (w->w_children[i] == child)
|
|
return (1);
|
|
}
|
|
for (i = 0; i < w->w_childcnt; i++) {
|
|
if (isitmydescendant(w->w_children[i], child))
|
|
return (1);
|
|
}
|
|
}
|
|
return (0);
|
|
}
|
|
|
|
void
|
|
witness_levelall (void)
|
|
{
|
|
struct witness *w, *w1;
|
|
|
|
for (w = w_all; w; w = w->w_next)
|
|
if (!(w->w_spin))
|
|
w->w_level = 0;
|
|
for (w = w_all; w; w = w->w_next) {
|
|
if (w->w_spin)
|
|
continue;
|
|
for (w1 = w_all; w1; w1 = w1->w_next) {
|
|
if (isitmychild(w1, w))
|
|
break;
|
|
}
|
|
if (w1 != NULL)
|
|
continue;
|
|
witness_leveldescendents(w, 0);
|
|
}
|
|
}
|
|
|
|
static void
|
|
witness_leveldescendents(struct witness *parent, int level)
|
|
{
|
|
int i;
|
|
struct witness *w;
|
|
|
|
if (parent->w_level < level)
|
|
parent->w_level = level;
|
|
level++;
|
|
for (w = parent; w != NULL; w = w->w_morechildren)
|
|
for (i = 0; i < w->w_childcnt; i++)
|
|
witness_leveldescendents(w->w_children[i], level);
|
|
}
|
|
|
|
static void
|
|
witness_displaydescendants(void(*prnt)(const char *fmt, ...),
|
|
struct witness *parent)
|
|
{
|
|
struct witness *w;
|
|
int i;
|
|
int level;
|
|
|
|
level = parent->w_spin ? ffs(parent->w_level) : parent->w_level;
|
|
|
|
prnt("%d", level);
|
|
if (level < 10)
|
|
prnt(" ");
|
|
for (i = 0; i < level; i++)
|
|
prnt(" ");
|
|
prnt("%s", parent->w_description);
|
|
if (parent->w_file != NULL)
|
|
prnt(" -- last acquired @ %s:%d\n", parent->w_file,
|
|
parent->w_line);
|
|
|
|
for (w = parent; w != NULL; w = w->w_morechildren)
|
|
for (i = 0; i < w->w_childcnt; i++)
|
|
witness_displaydescendants(prnt, w->w_children[i]);
|
|
}
|
|
|
|
static int
|
|
dup_ok(struct witness *w)
|
|
{
|
|
char **dup;
|
|
|
|
for (dup = dup_list; *dup!= NULL; dup++)
|
|
if (strcmp(w->w_description, *dup) == 0)
|
|
return (1);
|
|
return (0);
|
|
}
|
|
|
|
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_description, b->b_lock1) == 0) {
|
|
if (strcmp(w2->w_description, b->b_lock2) == 0)
|
|
return (1);
|
|
continue;
|
|
}
|
|
if (strcmp(w1->w_description, b->b_lock2) == 0)
|
|
if (strcmp(w2->w_description, b->b_lock1) == 0)
|
|
return (1);
|
|
}
|
|
return (0);
|
|
}
|
|
|
|
static struct witness *
|
|
witness_get()
|
|
{
|
|
struct witness *w;
|
|
|
|
if ((w = w_free) == NULL) {
|
|
witness_dead = 1;
|
|
mtx_unlock_spin_flags(&w_mtx, MTX_QUIET);
|
|
printf("witness exhausted\n");
|
|
return (NULL);
|
|
}
|
|
w_free = w->w_next;
|
|
bzero(w, sizeof(*w));
|
|
return (w);
|
|
}
|
|
|
|
static void
|
|
witness_free(struct witness *w)
|
|
{
|
|
w->w_next = w_free;
|
|
w_free = w;
|
|
}
|
|
|
|
int
|
|
witness_list(struct proc *p)
|
|
{
|
|
struct mtx *m;
|
|
int nheld;
|
|
|
|
KASSERT(!witness_cold, ("%s: witness_cold\n", __FUNCTION__));
|
|
nheld = 0;
|
|
LIST_FOREACH(m, &p->p_heldmtx, mtx_held) {
|
|
printf("\t\"%s\" (%p) locked at %s:%d\n",
|
|
m->mtx_description, m,
|
|
m->mtx_witness->w_file, m->mtx_witness->w_line);
|
|
nheld++;
|
|
}
|
|
|
|
return (nheld);
|
|
}
|
|
|
|
#ifdef DDB
|
|
|
|
DB_SHOW_COMMAND(mutexes, db_witness_list)
|
|
{
|
|
|
|
witness_list(curproc);
|
|
}
|
|
|
|
DB_SHOW_COMMAND(witness, db_witness_display)
|
|
{
|
|
|
|
witness_display(db_printf);
|
|
}
|
|
#endif
|
|
|
|
void
|
|
witness_save(struct mtx *m, const char **filep, int *linep)
|
|
{
|
|
|
|
KASSERT(!witness_cold, ("%s: witness_cold\n", __FUNCTION__));
|
|
if (m->mtx_witness == NULL)
|
|
return;
|
|
|
|
*filep = m->mtx_witness->w_file;
|
|
*linep = m->mtx_witness->w_line;
|
|
}
|
|
|
|
void
|
|
witness_restore(struct mtx *m, const char *file, int line)
|
|
{
|
|
|
|
KASSERT(!witness_cold, ("%s: witness_cold\n", __FUNCTION__));
|
|
if (m->mtx_witness == NULL)
|
|
return;
|
|
|
|
m->mtx_witness->w_file = file;
|
|
m->mtx_witness->w_line = line;
|
|
}
|
|
|
|
#endif /* WITNESS */
|