b7e554f5d6
may need the clock lock for nanotime(). - Add KTR trace events for lock list manipulations and other witness operations. - Use a temporary variable instead of setting the lock list head directly and then setting up the links to add a new lock list entry to the lock list. This small race could result in witness "forgetting" about all the locks held by this process temporarily during an interrupt. - Close a more fatal race condition when removing a lock from a list. Removing a lock from the list entails both decrementing the count of items in this bucket as well as shuffling items in the current bucket up a notch to replace the gap left by the removed item. Wrap these operations in a critical section.
1373 lines
36 KiB
C
1373 lines
36 KiB
C
/*-
|
|
* Copyright (c) 1998 Berkeley Software Design, Inc. All rights reserved.
|
|
*
|
|
* Redistribution and use in source and binary forms, with or without
|
|
* modification, are permitted provided that the following conditions
|
|
* are met:
|
|
* 1. Redistributions of source code must retain the above copyright
|
|
* notice, this list of conditions and the following disclaimer.
|
|
* 2. Redistributions in binary form must reproduce the above copyright
|
|
* notice, this list of conditions and the following disclaimer in the
|
|
* documentation and/or other materials provided with the distribution.
|
|
* 3. Berkeley Software Design Inc's name may not be used to endorse or
|
|
* promote products derived from this software without specific prior
|
|
* written permission.
|
|
*
|
|
* THIS SOFTWARE IS PROVIDED BY BERKELEY SOFTWARE DESIGN INC ``AS IS'' AND
|
|
* ANY EXPRESS OR IMPLIED WARRANTIES, INCLUDING, BUT NOT LIMITED TO, THE
|
|
* IMPLIED WARRANTIES OF MERCHANTABILITY AND FITNESS FOR A PARTICULAR PURPOSE
|
|
* ARE DISCLAIMED. IN NO EVENT SHALL BERKELEY SOFTWARE DESIGN INC BE LIABLE
|
|
* FOR ANY DIRECT, INDIRECT, INCIDENTAL, SPECIAL, EXEMPLARY, OR CONSEQUENTIAL
|
|
* DAMAGES (INCLUDING, BUT NOT LIMITED TO, PROCUREMENT OF SUBSTITUTE GOODS
|
|
* OR SERVICES; LOSS OF USE, DATA, OR PROFITS; OR BUSINESS INTERRUPTION)
|
|
* HOWEVER CAUSED AND ON ANY THEORY OF LIABILITY, WHETHER IN CONTRACT, STRICT
|
|
* LIABILITY, OR TORT (INCLUDING NEGLIGENCE OR OTHERWISE) ARISING IN ANY WAY
|
|
* OUT OF THE USE OF THIS SOFTWARE, EVEN IF ADVISED OF THE POSSIBILITY OF
|
|
* SUCH DAMAGE.
|
|
*
|
|
* from BSDI $Id: mutex_witness.c,v 1.1.2.20 2000/04/27 03:10:27 cp Exp $
|
|
* and BSDI $Id: synch_machdep.c,v 2.3.2.39 2000/04/27 03:10:25 cp Exp $
|
|
* $FreeBSD$
|
|
*/
|
|
|
|
/*
|
|
* Implementation of the `witness' lock verifier. Originally implemented for
|
|
* mutexes in BSD/OS. Extended to handle generic lock objects and lock
|
|
* classes in FreeBSD.
|
|
*/
|
|
|
|
/*
|
|
* Main Entry: witness
|
|
* Pronunciation: 'wit-n&s
|
|
* Function: noun
|
|
* Etymology: Middle English witnesse, from Old English witnes knowledge,
|
|
* testimony, witness, from 2wit
|
|
* Date: before 12th century
|
|
* 1 : attestation of a fact or event : TESTIMONY
|
|
* 2 : one that gives evidence; specifically : one who testifies in
|
|
* a cause or before a judicial tribunal
|
|
* 3 : one asked to be present at a transaction so as to be able to
|
|
* testify to its having taken place
|
|
* 4 : one who has personal knowledge of something
|
|
* 5 a : something serving as evidence or proof : SIGN
|
|
* b : public affirmation by word or example of usually
|
|
* religious faith or conviction <the heroic witness to divine
|
|
* life -- Pilot>
|
|
* 6 capitalized : a member of the Jehovah's Witnesses
|
|
*/
|
|
|
|
#include "opt_ddb.h"
|
|
#include "opt_witness.h"
|
|
|
|
#include <sys/param.h>
|
|
#include <sys/bus.h>
|
|
#include <sys/kernel.h>
|
|
#include <sys/ktr.h>
|
|
#include <sys/lock.h>
|
|
#include <sys/malloc.h>
|
|
#include <sys/mutex.h>
|
|
#include <sys/proc.h>
|
|
#include <sys/sysctl.h>
|
|
#include <sys/systm.h>
|
|
|
|
#include <ddb/ddb.h>
|
|
|
|
#define WITNESS_COUNT 200
|
|
#define WITNESS_CHILDCOUNT (WITNESS_COUNT * 4)
|
|
/*
|
|
* XXX: This is somewhat bogus, as we assume here that at most 1024 processes
|
|
* will hold LOCK_NCHILDREN * 2 locks. We handle failure ok, and we should
|
|
* probably be safe for the most part, but it's still a SWAG.
|
|
*/
|
|
#define LOCK_CHILDCOUNT (MAXCPU + 1024) * 2
|
|
|
|
#define WITNESS_NCHILDREN 6
|
|
|
|
struct witness_child_list_entry;
|
|
|
|
struct witness {
|
|
const char *w_name;
|
|
struct lock_class *w_class;
|
|
STAILQ_ENTRY(witness) w_list; /* List of all witnesses. */
|
|
STAILQ_ENTRY(witness) w_typelist; /* Witnesses of a type. */
|
|
struct witness_child_list_entry *w_children; /* Great evilness... */
|
|
const char *w_file;
|
|
int w_line;
|
|
u_int w_level;
|
|
u_int w_refcount;
|
|
u_char w_Giant_squawked:1;
|
|
u_char w_other_squawked:1;
|
|
u_char w_same_squawked:1;
|
|
};
|
|
|
|
struct witness_child_list_entry {
|
|
struct witness_child_list_entry *wcl_next;
|
|
struct witness *wcl_children[WITNESS_NCHILDREN];
|
|
u_int wcl_count;
|
|
};
|
|
|
|
STAILQ_HEAD(witness_list, witness);
|
|
|
|
struct witness_blessed {
|
|
const char *b_lock1;
|
|
const char *b_lock2;
|
|
};
|
|
|
|
struct witness_order_list_entry {
|
|
const char *w_name;
|
|
struct lock_class *w_class;
|
|
};
|
|
|
|
static struct witness *enroll(const char *description,
|
|
struct lock_class *lock_class);
|
|
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_display_list(void(*prnt)(const char *fmt, ...),
|
|
struct witness_list *list);
|
|
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 struct witness_child_list_entry *witness_child_get(void);
|
|
static void witness_child_free(struct witness_child_list_entry *wcl);
|
|
static struct lock_list_entry *witness_lock_list_get(void);
|
|
static void witness_lock_list_free(struct lock_list_entry *lle);
|
|
static void witness_display(void(*)(const char *fmt, ...));
|
|
static struct lock_instance *find_instance(struct lock_list_entry *lock_list,
|
|
struct lock_object *lock);
|
|
|
|
MALLOC_DEFINE(M_WITNESS, "witness", "witness structure");
|
|
|
|
static int witness_watch = 1;
|
|
TUNABLE_INT("debug.witness_watch", &witness_watch);
|
|
SYSCTL_INT(_debug, OID_AUTO, witness_watch, CTLFLAG_RD, &witness_watch, 0, "");
|
|
|
|
#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.
|
|
*/
|
|
#ifdef WITNESS_DDB
|
|
int witness_ddb = 1;
|
|
#else
|
|
int witness_ddb = 0;
|
|
#endif
|
|
TUNABLE_INT("debug.witness_ddb", &witness_ddb);
|
|
SYSCTL_INT(_debug, OID_AUTO, witness_ddb, CTLFLAG_RW, &witness_ddb, 0, "");
|
|
#endif /* DDB */
|
|
|
|
#ifdef WITNESS_SKIPSPIN
|
|
int witness_skipspin = 1;
|
|
#else
|
|
int witness_skipspin = 0;
|
|
#endif
|
|
TUNABLE_INT("debug.witness_skipspin", &witness_skipspin);
|
|
SYSCTL_INT(_debug, OID_AUTO, witness_skipspin, CTLFLAG_RD, &witness_skipspin, 0,
|
|
"");
|
|
|
|
static struct mtx w_mtx;
|
|
static struct witness_list w_free = STAILQ_HEAD_INITIALIZER(w_free);
|
|
static struct witness_list w_all = STAILQ_HEAD_INITIALIZER(w_all);
|
|
static struct witness_list w_spin = STAILQ_HEAD_INITIALIZER(w_spin);
|
|
static struct witness_list w_sleep = STAILQ_HEAD_INITIALIZER(w_sleep);
|
|
static struct witness_child_list_entry *w_child_free = NULL;
|
|
static struct lock_list_entry *w_lock_list_free = NULL;
|
|
static int witness_dead; /* fatal error, probably no memory */
|
|
|
|
static struct witness w_data[WITNESS_COUNT];
|
|
static struct witness_child_list_entry w_childdata[WITNESS_CHILDCOUNT];
|
|
static struct lock_list_entry w_locklistdata[LOCK_CHILDCOUNT];
|
|
|
|
static struct witness_order_list_entry order_lists[] = {
|
|
{ "Giant", &lock_class_mtx_sleep },
|
|
{ "proctree", &lock_class_sx },
|
|
{ "allproc", &lock_class_sx },
|
|
{ "process lock", &lock_class_mtx_sleep },
|
|
{ "uidinfo hash", &lock_class_mtx_sleep },
|
|
{ "uidinfo struct", &lock_class_mtx_sleep },
|
|
{ NULL, NULL },
|
|
/*
|
|
* spin locks
|
|
*/
|
|
#if defined(__i386__) && defined (SMP)
|
|
{ "com", &lock_class_mtx_spin },
|
|
#endif
|
|
{ "sio", &lock_class_mtx_spin },
|
|
#ifdef __i386__
|
|
{ "cy", &lock_class_mtx_spin },
|
|
#endif
|
|
{ "ng_node", &lock_class_mtx_spin },
|
|
{ "ng_worklist", &lock_class_mtx_spin },
|
|
{ "ithread table lock", &lock_class_mtx_spin },
|
|
{ "sched lock", &lock_class_mtx_spin },
|
|
{ "callout", &lock_class_mtx_spin },
|
|
/*
|
|
* leaf locks
|
|
*/
|
|
#ifdef SMP
|
|
{ "ap boot", &lock_class_mtx_spin },
|
|
#ifdef __i386__
|
|
{ "imen", &lock_class_mtx_spin },
|
|
#endif
|
|
{ "smp rendezvous", &lock_class_mtx_spin },
|
|
#endif
|
|
{ "clk", &lock_class_mtx_spin },
|
|
{ NULL, NULL },
|
|
{ NULL, NULL }
|
|
};
|
|
|
|
static const char *dup_list[] = {
|
|
"process lock",
|
|
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);
|
|
|
|
/*
|
|
* List of all locks in the system.
|
|
*/
|
|
STAILQ_HEAD(, lock_object) all_locks = STAILQ_HEAD_INITIALIZER(all_locks);
|
|
|
|
static struct mtx all_mtx = {
|
|
{ &lock_class_mtx_sleep, /* mtx_object.lo_class */
|
|
"All locks list", /* mtx_object.lo_name */
|
|
LO_INITIALIZED, /* mtx_object.lo_flags */
|
|
{ NULL }, /* mtx_object.lo_list */
|
|
NULL }, /* mtx_object.lo_witness */
|
|
MTX_UNOWNED, 0, /* mtx_lock, mtx_recurse */
|
|
0, /* mtx_savecrit */
|
|
TAILQ_HEAD_INITIALIZER(all_mtx.mtx_blocked),
|
|
{ NULL, NULL } /* mtx_contested */
|
|
};
|
|
|
|
/*
|
|
* This global is set to 0 once it becomes safe to use the witness code.
|
|
*/
|
|
static int witness_cold = 1;
|
|
|
|
/*
|
|
* Global variables for book keeping.
|
|
*/
|
|
static int lock_cur_cnt;
|
|
static int lock_max_cnt;
|
|
|
|
/*
|
|
* The WITNESS-enabled diagnostic code.
|
|
*/
|
|
static void
|
|
witness_initialize(void *dummy __unused)
|
|
{
|
|
struct lock_object *lock;
|
|
struct witness_order_list_entry *order;
|
|
struct witness *w, *w1;
|
|
int i;
|
|
|
|
/*
|
|
* 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__);
|
|
STAILQ_INSERT_HEAD(&all_locks, &all_mtx.mtx_object, lo_list);
|
|
mtx_init(&w_mtx, "witness lock", MTX_SPIN | MTX_QUIET | MTX_NOWITNESS);
|
|
for (i = 0; i < WITNESS_COUNT; i++)
|
|
witness_free(&w_data[i]);
|
|
for (i = 0; i < WITNESS_CHILDCOUNT; i++)
|
|
witness_child_free(&w_childdata[i]);
|
|
for (i = 0; i < LOCK_CHILDCOUNT; i++)
|
|
witness_lock_list_free(&w_locklistdata[i]);
|
|
|
|
/* 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;
|
|
}
|
|
}
|
|
|
|
/* Iterate through all locks and add them to witness. */
|
|
mtx_lock(&all_mtx);
|
|
STAILQ_FOREACH(lock, &all_locks, lo_list) {
|
|
if (lock->lo_flags & LO_WITNESS)
|
|
lock->lo_witness = enroll(lock->lo_name,
|
|
lock->lo_class);
|
|
else
|
|
lock->lo_witness = NULL;
|
|
}
|
|
mtx_unlock(&all_mtx);
|
|
|
|
/* Mark the witness code as being ready for use. */
|
|
atomic_store_rel_int(&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)
|
|
{
|
|
struct lock_class *class;
|
|
|
|
class = lock->lo_class;
|
|
if (lock->lo_flags & LO_INITIALIZED)
|
|
panic("%s: lock (%s) %s is already initialized!\n", __func__,
|
|
class->lc_name, lock->lo_name);
|
|
|
|
if ((lock->lo_flags & LO_RECURSABLE) != 0 &&
|
|
(class->lc_flags & LC_RECURSABLE) == 0)
|
|
panic("%s: lock (%s) %s can not be recursable!\n", __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!\n", __func__,
|
|
class->lc_name, lock->lo_name);
|
|
|
|
mtx_lock(&all_mtx);
|
|
STAILQ_INSERT_TAIL(&all_locks, lock, lo_list);
|
|
lock->lo_flags |= LO_INITIALIZED;
|
|
lock_cur_cnt++;
|
|
if (lock_cur_cnt > lock_max_cnt)
|
|
lock_max_cnt = lock_cur_cnt;
|
|
mtx_unlock(&all_mtx);
|
|
if (!witness_cold && !witness_dead &&
|
|
(lock->lo_flags & LO_WITNESS) != 0)
|
|
lock->lo_witness = enroll(lock->lo_name, class);
|
|
else
|
|
lock->lo_witness = NULL;
|
|
}
|
|
|
|
void
|
|
witness_destroy(struct lock_object *lock)
|
|
{
|
|
struct witness *w;
|
|
|
|
if (witness_cold)
|
|
panic("lock (%s) %s destroyed while witness_cold",
|
|
lock->lo_class->lc_name, lock->lo_name);
|
|
|
|
if ((lock->lo_flags & LO_INITIALIZED) == 0)
|
|
panic("%s: lock (%s) %s is not initialized!\n", __func__,
|
|
lock->lo_class->lc_name, lock->lo_name);
|
|
|
|
/* XXX: need to verify that no one holds the lock */
|
|
w = lock->lo_witness;
|
|
if (w != NULL) {
|
|
mtx_lock_spin(&w_mtx);
|
|
w->w_refcount--;
|
|
if (w->w_refcount == 0) {
|
|
CTR1(KTR_WITNESS, "Marking witness %s as dead",
|
|
w->w_name);
|
|
w->w_name = "(dead)";
|
|
w->w_file = "(dead)";
|
|
w->w_line = 0;
|
|
}
|
|
mtx_unlock_spin(&w_mtx);
|
|
}
|
|
|
|
mtx_lock(&all_mtx);
|
|
lock_cur_cnt--;
|
|
STAILQ_REMOVE(&all_locks, lock, lock_object, lo_list);
|
|
lock->lo_flags &= LO_INITIALIZED;
|
|
mtx_unlock(&all_mtx);
|
|
}
|
|
|
|
static void
|
|
witness_display_list(void(*prnt)(const char *fmt, ...),
|
|
struct witness_list *list)
|
|
{
|
|
struct witness *w, *w1;
|
|
int found;
|
|
|
|
STAILQ_FOREACH(w, list, w_typelist) {
|
|
if (w->w_file == NULL)
|
|
continue;
|
|
found = 0;
|
|
STAILQ_FOREACH(w1, list, w_typelist) {
|
|
if (isitmychild(w1, w)) {
|
|
found++;
|
|
break;
|
|
}
|
|
}
|
|
if (found)
|
|
continue;
|
|
/*
|
|
* This lock has no anscestors, display its descendants.
|
|
*/
|
|
witness_displaydescendants(prnt, w);
|
|
}
|
|
}
|
|
|
|
static void
|
|
witness_display(void(*prnt)(const char *fmt, ...))
|
|
{
|
|
struct witness *w;
|
|
|
|
KASSERT(!witness_cold, ("%s: witness_cold\n", __func__));
|
|
witness_levelall();
|
|
|
|
/*
|
|
* First, handle sleep locks which have been acquired at least
|
|
* once.
|
|
*/
|
|
prnt("Sleep locks:\n");
|
|
witness_display_list(prnt, &w_sleep);
|
|
|
|
/*
|
|
* Now do spin locks which have been acquired at least once.
|
|
*/
|
|
prnt("\nSpin locks:\n");
|
|
witness_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)
|
|
continue;
|
|
prnt("%s\n", w->w_name);
|
|
}
|
|
}
|
|
|
|
void
|
|
witness_lock(struct lock_object *lock, int flags, const char *file, int line)
|
|
{
|
|
struct lock_list_entry **lock_list, *lle;
|
|
struct lock_instance *lock1, *lock2;
|
|
struct lock_class *class;
|
|
struct witness *w, *w1;
|
|
struct proc *p;
|
|
int i, j;
|
|
#ifdef DDB
|
|
int go_into_ddb = 0;
|
|
#endif /* DDB */
|
|
|
|
if (witness_cold || witness_dead || lock->lo_witness == NULL ||
|
|
panicstr)
|
|
return;
|
|
w = lock->lo_witness;
|
|
class = lock->lo_class;
|
|
p = curproc;
|
|
|
|
/*
|
|
* We have to hold a spinlock to keep lock_list valid across the check
|
|
* in the LC_SLEEPLOCK case. In the LC_SPINLOCK case, it is already
|
|
* protected by the spinlock we are currently performing the witness
|
|
* checks on, so it is ok to release the lock after performing this
|
|
* check. All we have to protect is the LC_SLEEPLOCK case when no
|
|
* spinlocks are held as we may get preempted during this check and
|
|
* lock_list could end up pointing to some other CPU's spinlock list.
|
|
*/
|
|
mtx_lock_spin(&w_mtx);
|
|
lock_list = PCPU_PTR(spinlocks);
|
|
if (class->lc_flags & LC_SLEEPLOCK) {
|
|
if (*lock_list != NULL && (flags & LOP_TRYLOCK) == 0) {
|
|
mtx_unlock_spin(&w_mtx);
|
|
panic("blockable sleep lock (%s) %s @ %s:%d",
|
|
class->lc_name, lock->lo_name, file, line);
|
|
}
|
|
lock_list = &p->p_sleeplocks;
|
|
}
|
|
mtx_unlock_spin(&w_mtx);
|
|
|
|
/*
|
|
* Try locks do not block if they fail to acquire the lock, thus
|
|
* there is no danger of deadlocks or of switching while holding a
|
|
* spin lock if we acquire a lock via a try operation.
|
|
*/
|
|
if (flags & LOP_TRYLOCK)
|
|
goto out;
|
|
|
|
/*
|
|
* Is this the first lock acquired? If so, then no order checking
|
|
* is needed.
|
|
*/
|
|
if (*lock_list == NULL)
|
|
goto out;
|
|
|
|
/*
|
|
* Check to see if we are recursing on a lock we already own.
|
|
*/
|
|
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");
|
|
}
|
|
lock1->li_flags++;
|
|
if ((lock->lo_flags & LO_RECURSABLE) == 0) {
|
|
printf(
|
|
"recursed on non-recursive lock (%s) %s @ %s:%d\n",
|
|
class->lc_name, lock->lo_name, file, line);
|
|
printf("first acquired @ %s:%d\n", lock1->li_file,
|
|
lock1->li_line);
|
|
panic("recurse");
|
|
}
|
|
CTR3(KTR_WITNESS, "witness_lock: pid %d recursed on %s r=%d",
|
|
curproc->p_pid, lock->lo_name,
|
|
lock1->li_flags & LI_RECURSEMASK);
|
|
lock1->li_file = file;
|
|
lock1->li_line = line;
|
|
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.
|
|
*/
|
|
lock1 = &(*lock_list)->ll_children[(*lock_list)->ll_count - 1];
|
|
w1 = lock1->li_lock->lo_witness;
|
|
if (w1 == w) {
|
|
if (w->w_same_squawked || dup_ok(w))
|
|
goto out;
|
|
w->w_same_squawked = 1;
|
|
printf("acquiring duplicate lock of same type: \"%s\"\n",
|
|
lock->lo_name);
|
|
printf(" 1st @ %s:%d\n", lock1->li_file, lock1->li_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(&w_mtx);
|
|
/*
|
|
* If we have a known higher number just say ok
|
|
*/
|
|
if (witness_watch > 1 && w->w_level > w1->w_level) {
|
|
mtx_unlock_spin(&w_mtx);
|
|
goto out;
|
|
}
|
|
if (isitmydescendant(w1, w)) {
|
|
mtx_unlock_spin(&w_mtx);
|
|
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];
|
|
w1 = lock1->li_lock->lo_witness;
|
|
|
|
/*
|
|
* If this lock doesn't undergo witness checking,
|
|
* then skip it.
|
|
*/
|
|
if (w1 == NULL) {
|
|
KASSERT((lock1->li_lock->lo_flags & LO_WITNESS) == 0,
|
|
("lock missing witness structure"));
|
|
continue;
|
|
}
|
|
/*
|
|
* If we are locking Giant and we slept with this
|
|
* lock, then skip it.
|
|
*/
|
|
if ((lock1->li_flags & LI_SLEPT) != 0 &&
|
|
lock == &Giant.mtx_object)
|
|
continue;
|
|
if (!isitmydescendant(w, w1))
|
|
continue;
|
|
/*
|
|
* We have a lock order violation, check to see if it
|
|
* is allowed or has already been yelled about.
|
|
*/
|
|
mtx_unlock_spin(&w_mtx);
|
|
if (blessed(w, w1))
|
|
goto out;
|
|
if (lock1->li_lock == &Giant.mtx_object) {
|
|
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;
|
|
}
|
|
/*
|
|
* Ok, yell about it.
|
|
*/
|
|
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;
|
|
i--;
|
|
if (i == 0 && lle->ll_next != NULL) {
|
|
lle = lle->ll_next;
|
|
i = lle->ll_count - 1;
|
|
MPASS(i != 0);
|
|
}
|
|
} while (i >= 0);
|
|
if (i < 0) {
|
|
printf(" 1st %p %s @ %s:%d\n", lock1->li_lock,
|
|
lock1->li_lock->lo_name, lock1->li_file,
|
|
lock1->li_line);
|
|
printf(" 2nd %p %s @ %s:%d\n", lock,
|
|
lock->lo_name, file, line);
|
|
} else {
|
|
printf(" 1st %p %s @ %s:%d\n", lock2->li_lock,
|
|
lock2->li_lock->lo_name, lock2->li_file,
|
|
lock2->li_line);
|
|
printf(" 2nd %p %s @ %s:%d\n", lock1->li_lock,
|
|
lock1->li_lock->lo_name, lock1->li_file,
|
|
lock1->li_line);
|
|
printf(" 3rd %p %s @ %s:%d\n", lock,
|
|
lock->lo_name, file, line);
|
|
}
|
|
#ifdef DDB
|
|
go_into_ddb = 1;
|
|
#endif /* DDB */
|
|
goto out;
|
|
}
|
|
}
|
|
lock1 = &(*lock_list)->ll_children[(*lock_list)->ll_count - 1];
|
|
CTR2(KTR_WITNESS, "Adding %s as a child of %s", lock->lo_name,
|
|
lock1->li_lock->lo_name);
|
|
if (!itismychild(lock1->li_lock->lo_witness, w))
|
|
mtx_unlock_spin(&w_mtx);
|
|
|
|
out:
|
|
#ifdef DDB
|
|
if (witness_ddb && go_into_ddb)
|
|
Debugger(__func__);
|
|
#endif /* DDB */
|
|
w->w_file = file;
|
|
w->w_line = line;
|
|
|
|
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;
|
|
CTR2(KTR_WITNESS, "witness_lock: pid %d added lle %p",
|
|
curproc->p_pid, lle);
|
|
*lock_list = lle;
|
|
}
|
|
lock1 = &lle->ll_children[lle->ll_count++];
|
|
lock1->li_lock = lock;
|
|
lock1->li_line = line;
|
|
lock1->li_file = file;
|
|
if ((flags & LOP_EXCLUSIVE) != 0)
|
|
lock1->li_flags = LI_EXCLUSIVE;
|
|
else
|
|
lock1->li_flags = 0;
|
|
CTR3(KTR_WITNESS, "witness_lock: pid %d added %s as lle[%d]",
|
|
curproc->p_pid, lock->lo_name, lle->ll_count - 1);
|
|
}
|
|
|
|
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 proc *p;
|
|
critical_t s;
|
|
int i, j;
|
|
|
|
if (witness_cold || witness_dead || lock->lo_witness == NULL ||
|
|
panicstr)
|
|
return;
|
|
p = curproc;
|
|
class = lock->lo_class;
|
|
if (class->lc_flags & LC_SLEEPLOCK)
|
|
lock_list = &p->p_sleeplocks;
|
|
else
|
|
lock_list = PCPU_PTR(spinlocks);
|
|
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) {
|
|
if ((instance->li_flags & LI_EXCLUSIVE) != 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 &&
|
|
(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) {
|
|
CTR3(KTR_WITNESS,
|
|
"witness_unlock: pid %d unrecursed on %s r=%d",
|
|
curproc->p_pid,
|
|
instance->li_lock->lo_name,
|
|
instance->li_flags);
|
|
instance->li_flags--;
|
|
goto out;
|
|
}
|
|
s = critical_enter();
|
|
CTR3(KTR_WITNESS,
|
|
"witness_unlock: pid %d removed %s from lle[%d]",
|
|
curproc->p_pid, instance->li_lock->lo_name,
|
|
(*lock_list)->ll_count - 1);
|
|
(*lock_list)->ll_count--;
|
|
for (j = i; j < (*lock_list)->ll_count; j++)
|
|
(*lock_list)->ll_children[j] =
|
|
(*lock_list)->ll_children[j + 1];
|
|
critical_exit(s);
|
|
if ((*lock_list)->ll_count == 0) {
|
|
lle = *lock_list;
|
|
*lock_list = lle->ll_next;
|
|
CTR2(KTR_WITNESS,
|
|
"witness_unlock: pid %d removed lle %p",
|
|
curproc->p_pid, lle);
|
|
witness_lock_list_free(lle);
|
|
}
|
|
goto out;
|
|
}
|
|
}
|
|
panic("lock (%s) %s not locked @ %s:%d", class->lc_name, lock->lo_name,
|
|
file, line);
|
|
out:
|
|
/*
|
|
* We don't need to protect this PCPU_GET() here against preemption
|
|
* because if we hold any spinlocks then we are already protected,
|
|
* and if we don't we will get NULL if we hold no spinlocks even if
|
|
* we switch CPU's while reading it.
|
|
*/
|
|
if (class->lc_flags & LC_SLEEPLOCK) {
|
|
if ((flags & LOP_NOSWITCH) == 0 && PCPU_GET(spinlocks) != NULL)
|
|
panic("switchable sleep unlock (%s) %s @ %s:%d",
|
|
class->lc_name, lock->lo_name, file, line);
|
|
}
|
|
}
|
|
|
|
/*
|
|
* Warn if any held locks are not sleepable. Note that Giant and the lock
|
|
* passed in are both special cases since they are both released during the
|
|
* sleep process and aren't actually held while the process is asleep.
|
|
*/
|
|
int
|
|
witness_sleep(int check_only, struct lock_object *lock, const char *file,
|
|
int line)
|
|
{
|
|
struct lock_list_entry **lock_list, *lle;
|
|
struct lock_instance *lock1;
|
|
struct proc *p;
|
|
critical_t savecrit;
|
|
int i, n;
|
|
|
|
if (witness_dead || panicstr)
|
|
return (0);
|
|
KASSERT(!witness_cold, ("%s: witness_cold\n", __func__));
|
|
n = 0;
|
|
/*
|
|
* Preemption bad because we need PCPU_PTR(spinlocks) to not change.
|
|
*/
|
|
savecrit = critical_enter();
|
|
p = curproc;
|
|
lock_list = &p->p_sleeplocks;
|
|
again:
|
|
for (lle = *lock_list; 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 ||
|
|
lock1->li_lock == &Giant.mtx_object)
|
|
continue;
|
|
if ((lock1->li_lock->lo_flags & LO_SLEEPABLE) != 0) {
|
|
if (check_only == 0) {
|
|
CTR3(KTR_WITNESS,
|
|
"pid %d: sleeping with (%s) %s held",
|
|
curproc->p_pid,
|
|
lock1->li_lock->lo_class->lc_name,
|
|
lock1->li_lock->lo_name);
|
|
lock1->li_flags |= LI_SLEPT;
|
|
}
|
|
continue;
|
|
}
|
|
n++;
|
|
printf("%s:%d: %s with \"%s\" locked from %s:%d\n",
|
|
file, line, check_only ? "could sleep" : "sleeping",
|
|
lock1->li_lock->lo_name, lock1->li_file,
|
|
lock1->li_line);
|
|
}
|
|
if (lock_list == &p->p_sleeplocks) {
|
|
lock_list = PCPU_PTR(spinlocks);
|
|
goto again;
|
|
}
|
|
#ifdef DDB
|
|
if (witness_ddb && n)
|
|
Debugger(__func__);
|
|
#endif /* DDB */
|
|
critical_exit(savecrit);
|
|
return (n);
|
|
}
|
|
|
|
static struct witness *
|
|
enroll(const char *description, struct lock_class *lock_class)
|
|
{
|
|
struct witness *w;
|
|
|
|
if (!witness_watch || witness_dead)
|
|
return (NULL);
|
|
|
|
if ((lock_class->lc_flags & LC_SPINLOCK) && witness_skipspin)
|
|
return (NULL);
|
|
mtx_lock_spin(&w_mtx);
|
|
STAILQ_FOREACH(w, &w_all, w_list) {
|
|
if (strcmp(description, w->w_name) == 0) {
|
|
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);
|
|
}
|
|
}
|
|
/*
|
|
* This isn't quite right, as witness_cold is still 0 while we
|
|
* enroll all the locks initialized before witness_initialize().
|
|
*/
|
|
if ((lock_class->lc_flags & LC_SPINLOCK) && !witness_cold) {
|
|
mtx_unlock_spin(&w_mtx);
|
|
panic("spin lock %s not in order list", description);
|
|
}
|
|
if ((w = witness_get()) == NULL)
|
|
return (NULL);
|
|
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);
|
|
else if (lock_class->lc_flags & LC_SLEEPLOCK)
|
|
STAILQ_INSERT_HEAD(&w_sleep, w, w_typelist);
|
|
else {
|
|
mtx_unlock_spin(&w_mtx);
|
|
panic("lock class %s is not sleep or spin",
|
|
lock_class->lc_name);
|
|
}
|
|
mtx_unlock_spin(&w_mtx);
|
|
|
|
return (w);
|
|
}
|
|
|
|
static int
|
|
itismychild(struct witness *parent, struct witness *child)
|
|
{
|
|
static int recursed;
|
|
struct witness_child_list_entry **wcl;
|
|
struct witness_list *list;
|
|
|
|
MPASS(child != NULL && parent != NULL);
|
|
if ((parent->w_class->lc_flags & (LC_SLEEPLOCK | LC_SPINLOCK)) !=
|
|
(child->w_class->lc_flags & (LC_SLEEPLOCK | LC_SPINLOCK)))
|
|
panic(
|
|
"%s: parent (%s) and child (%s) are not the same lock type",
|
|
__func__, parent->w_class->lc_name,
|
|
child->w_class->lc_name);
|
|
|
|
/*
|
|
* Insert "child" after "parent"
|
|
*/
|
|
wcl = &parent->w_children;
|
|
while (*wcl != NULL && (*wcl)->wcl_count == WITNESS_NCHILDREN)
|
|
wcl = &(*wcl)->wcl_next;
|
|
|
|
if (*wcl == NULL) {
|
|
*wcl = witness_child_get();
|
|
if (*wcl == NULL)
|
|
return (1);
|
|
}
|
|
|
|
(*wcl)->wcl_children[(*wcl)->wcl_count++] = child;
|
|
|
|
/*
|
|
* Now prune whole tree. We look for cases where a lock is now
|
|
* both a descendant and a direct child of a given lock. In that
|
|
* case, we want to remove the direct child link from the tree.
|
|
*/
|
|
if (recursed)
|
|
return (0);
|
|
recursed = 1;
|
|
if (parent->w_class->lc_flags & LC_SLEEPLOCK)
|
|
list = &w_sleep;
|
|
else
|
|
list = &w_spin;
|
|
STAILQ_FOREACH(child, list, w_typelist) {
|
|
STAILQ_FOREACH(parent, list, w_typelist) {
|
|
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_child_list_entry **wcl, *wcl1;
|
|
int i;
|
|
|
|
for (wcl = &parent->w_children; *wcl != NULL; wcl = &(*wcl)->wcl_next)
|
|
for (i = 0; i < (*wcl)->wcl_count; i++)
|
|
if ((*wcl)->wcl_children[i] == child)
|
|
goto found;
|
|
return;
|
|
found:
|
|
(*wcl)->wcl_count--;
|
|
if ((*wcl)->wcl_count > i)
|
|
(*wcl)->wcl_children[i] =
|
|
(*wcl)->wcl_children[(*wcl)->wcl_count];
|
|
MPASS((*wcl)->wcl_children[i] != NULL);
|
|
|
|
if ((*wcl)->wcl_count != 0)
|
|
return;
|
|
|
|
wcl1 = *wcl;
|
|
*wcl = wcl1->wcl_next;
|
|
witness_child_free(wcl1);
|
|
}
|
|
|
|
static int
|
|
isitmychild(struct witness *parent, struct witness *child)
|
|
{
|
|
struct witness_child_list_entry *wcl;
|
|
int i;
|
|
|
|
for (wcl = parent->w_children; wcl != NULL; wcl = wcl->wcl_next) {
|
|
for (i = 0; i < wcl->wcl_count; i++) {
|
|
if (wcl->wcl_children[i] == child)
|
|
return (1);
|
|
}
|
|
}
|
|
return (0);
|
|
}
|
|
|
|
static int
|
|
isitmydescendant(struct witness *parent, struct witness *child)
|
|
{
|
|
struct witness_child_list_entry *wcl;
|
|
int i, j;
|
|
|
|
if (isitmychild(parent, child))
|
|
return (1);
|
|
j = 0;
|
|
for (wcl = parent->w_children; wcl != NULL; wcl = wcl->wcl_next) {
|
|
MPASS(j < 1000);
|
|
for (i = 0; i < wcl->wcl_count; i++) {
|
|
if (isitmydescendant(wcl->wcl_children[i], child))
|
|
return (1);
|
|
}
|
|
j++;
|
|
}
|
|
return (0);
|
|
}
|
|
|
|
void
|
|
witness_levelall (void)
|
|
{
|
|
struct witness_list *list;
|
|
struct witness *w, *w1;
|
|
|
|
/*
|
|
* First clear all levels.
|
|
*/
|
|
STAILQ_FOREACH(w, &w_all, w_list) {
|
|
w->w_level = 0;
|
|
}
|
|
|
|
/*
|
|
* Look for locks with no parent and level all their descendants.
|
|
*/
|
|
STAILQ_FOREACH(w, &w_all, w_list) {
|
|
/*
|
|
* This is just an optimization, technically we could get
|
|
* away just walking the all list each time.
|
|
*/
|
|
if (w->w_class->lc_flags & LC_SLEEPLOCK)
|
|
list = &w_sleep;
|
|
else
|
|
list = &w_spin;
|
|
STAILQ_FOREACH(w1, list, w_typelist) {
|
|
if (isitmychild(w1, w))
|
|
goto skip;
|
|
}
|
|
witness_leveldescendents(w, 0);
|
|
skip:
|
|
}
|
|
}
|
|
|
|
static void
|
|
witness_leveldescendents(struct witness *parent, int level)
|
|
{
|
|
struct witness_child_list_entry *wcl;
|
|
int i;
|
|
|
|
if (parent->w_level < level)
|
|
parent->w_level = level;
|
|
level++;
|
|
for (wcl = parent->w_children; wcl != NULL; wcl = wcl->wcl_next)
|
|
for (i = 0; i < wcl->wcl_count; i++)
|
|
witness_leveldescendents(wcl->wcl_children[i], level);
|
|
}
|
|
|
|
static void
|
|
witness_displaydescendants(void(*prnt)(const char *fmt, ...),
|
|
struct witness *parent)
|
|
{
|
|
struct witness_child_list_entry *wcl;
|
|
int i, level;
|
|
|
|
level = parent->w_level;
|
|
|
|
prnt("%-2d", level);
|
|
for (i = 0; i < level; i++)
|
|
prnt(" ");
|
|
prnt("%s", parent->w_name);
|
|
if (parent->w_file != NULL)
|
|
prnt(" -- last acquired @ %s:%d\n", parent->w_file,
|
|
parent->w_line);
|
|
|
|
for (wcl = parent->w_children; wcl != NULL; wcl = wcl->wcl_next)
|
|
for (i = 0; i < wcl->wcl_count; i++)
|
|
witness_displaydescendants(prnt,
|
|
wcl->wcl_children[i]);
|
|
}
|
|
|
|
static int
|
|
dup_ok(struct witness *w)
|
|
{
|
|
const char **dup;
|
|
|
|
for (dup = dup_list; *dup != NULL; dup++)
|
|
if (strcmp(w->w_name, *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_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);
|
|
}
|
|
|
|
static struct witness *
|
|
witness_get(void)
|
|
{
|
|
struct witness *w;
|
|
|
|
if (witness_dead) {
|
|
mtx_unlock_spin(&w_mtx);
|
|
return (NULL);
|
|
}
|
|
if (STAILQ_EMPTY(&w_free)) {
|
|
witness_dead = 1;
|
|
mtx_unlock_spin(&w_mtx);
|
|
printf("%s: witness exhausted\n", __func__);
|
|
return (NULL);
|
|
}
|
|
w = STAILQ_FIRST(&w_free);
|
|
STAILQ_REMOVE_HEAD(&w_free, w_list);
|
|
bzero(w, sizeof(*w));
|
|
return (w);
|
|
}
|
|
|
|
static void
|
|
witness_free(struct witness *w)
|
|
{
|
|
|
|
STAILQ_INSERT_HEAD(&w_free, w, w_list);
|
|
}
|
|
|
|
static struct witness_child_list_entry *
|
|
witness_child_get(void)
|
|
{
|
|
struct witness_child_list_entry *wcl;
|
|
|
|
if (witness_dead) {
|
|
mtx_unlock_spin(&w_mtx);
|
|
return (NULL);
|
|
}
|
|
wcl = w_child_free;
|
|
if (wcl == NULL) {
|
|
witness_dead = 1;
|
|
mtx_unlock_spin(&w_mtx);
|
|
printf("%s: witness exhausted\n", __func__);
|
|
return (NULL);
|
|
}
|
|
w_child_free = wcl->wcl_next;
|
|
bzero(wcl, sizeof(*wcl));
|
|
return (wcl);
|
|
}
|
|
|
|
static void
|
|
witness_child_free(struct witness_child_list_entry *wcl)
|
|
{
|
|
|
|
wcl->wcl_next = w_child_free;
|
|
w_child_free = wcl;
|
|
}
|
|
|
|
static struct lock_list_entry *
|
|
witness_lock_list_get(void)
|
|
{
|
|
struct lock_list_entry *lle;
|
|
|
|
if (witness_dead)
|
|
return (NULL);
|
|
mtx_lock_spin(&w_mtx);
|
|
lle = w_lock_list_free;
|
|
if (lle == NULL) {
|
|
witness_dead = 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 *lock_list, struct lock_object *lock)
|
|
{
|
|
struct lock_list_entry *lle;
|
|
struct lock_instance *instance;
|
|
int i;
|
|
|
|
for (lle = lock_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);
|
|
}
|
|
|
|
int
|
|
witness_list_locks(struct lock_list_entry **lock_list)
|
|
{
|
|
struct lock_list_entry *lle;
|
|
struct lock_instance *instance;
|
|
struct lock_object *lock;
|
|
int i, nheld;
|
|
|
|
nheld = 0;
|
|
for (lle = *lock_list; lle != NULL; lle = lle->ll_next)
|
|
for (i = lle->ll_count - 1; i >= 0; i--) {
|
|
instance = &lle->ll_children[i];
|
|
lock = instance->li_lock;
|
|
printf("%s (%s) %s (%p) locked @ %s:%d\n",
|
|
(instance->li_flags & LI_EXCLUSIVE) != 0 ?
|
|
"exclusive" : "shared",
|
|
lock->lo_class->lc_name, lock->lo_name, lock,
|
|
instance->li_file, instance->li_line);
|
|
nheld++;
|
|
}
|
|
return (nheld);
|
|
}
|
|
|
|
/*
|
|
* Calling this on p != curproc is bad unless we are in ddb.
|
|
*/
|
|
int
|
|
witness_list(struct proc *p)
|
|
{
|
|
critical_t savecrit;
|
|
int nheld;
|
|
|
|
KASSERT(p == curproc || db_active,
|
|
("%s: p != curproc and we aren't in the debugger", __func__));
|
|
KASSERT(!witness_cold, ("%s: witness_cold", __func__));
|
|
|
|
if (!db_active && witness_dead)
|
|
return (0);
|
|
|
|
nheld = witness_list_locks(&p->p_sleeplocks);
|
|
|
|
/*
|
|
* We only handle spinlocks if p == curproc. This is somewhat broken
|
|
* if p 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 p->p_oncpu to
|
|
* get the list of spinlocks for this process and "fix" this.
|
|
*/
|
|
if (p == curproc) {
|
|
/*
|
|
* Preemption bad because we need PCPU_PTR(spinlocks) to not
|
|
* change.
|
|
*/
|
|
savecrit = critical_enter();
|
|
nheld += witness_list_locks(PCPU_PTR(spinlocks));
|
|
critical_exit(savecrit);
|
|
}
|
|
|
|
return (nheld);
|
|
}
|
|
|
|
void
|
|
witness_save(struct lock_object *lock, const char **filep, int *linep)
|
|
{
|
|
struct lock_instance *instance;
|
|
|
|
KASSERT(!witness_cold, ("%s: witness_cold\n", __func__));
|
|
if (lock->lo_witness == NULL || witness_dead)
|
|
return;
|
|
|
|
KASSERT(lock->lo_class->lc_flags & LC_SLEEPLOCK,
|
|
("%s: lock (%s) %s is not a sleep lock", __func__,
|
|
lock->lo_class->lc_name, lock->lo_name));
|
|
instance = find_instance(curproc->p_sleeplocks, lock);
|
|
KASSERT(instance != NULL, ("%s: lock (%s) %s not locked", __func__,
|
|
lock->lo_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_instance *instance;
|
|
|
|
KASSERT(!witness_cold, ("%s: witness_cold\n", __func__));
|
|
if (lock->lo_witness == NULL || witness_dead)
|
|
return;
|
|
|
|
KASSERT(lock->lo_class->lc_flags & LC_SLEEPLOCK,
|
|
("%s: lock (%s) %s is not a sleep lock", __func__,
|
|
lock->lo_class->lc_name, lock->lo_name));
|
|
instance = find_instance(curproc->p_sleeplocks, lock);
|
|
KASSERT(instance != NULL, ("%s: lock (%s) %s not locked", __func__,
|
|
lock->lo_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;
|
|
}
|
|
|
|
#ifdef DDB
|
|
|
|
DB_SHOW_COMMAND(locks, db_witness_list)
|
|
{
|
|
struct proc *p;
|
|
pid_t pid;
|
|
|
|
if (have_addr) {
|
|
pid = (addr % 16) + ((addr >> 4) % 16) * 10 +
|
|
((addr >> 8) % 16) * 100 + ((addr >> 12) % 16) * 1000 +
|
|
((addr >> 16) % 16) * 10000;
|
|
|
|
/* sx_slock(&allproc_lock); */
|
|
LIST_FOREACH(p, &allproc, p_list) {
|
|
if (p->p_pid == pid)
|
|
break;
|
|
}
|
|
/* sx_sunlock(&allproc_lock); */
|
|
if (p == NULL) {
|
|
db_printf("pid %d not found\n", pid);
|
|
return;
|
|
}
|
|
} else
|
|
p = curproc;
|
|
|
|
witness_list(p);
|
|
}
|
|
|
|
DB_SHOW_COMMAND(witness, db_witness_display)
|
|
{
|
|
|
|
witness_display(db_printf);
|
|
}
|
|
#endif
|