8484de7555
mtx right now as it makes debugging harder. When we are in optimizing mode, we can revisit this. - Fix the KTR trace messages to use %p rather than 0x%p to avoid duplicate 0x's in KTR output. - During witness_fixup, release Giant so that witness doesn't get confused. Also, grab all_mtx while walking the list of mutexes. - Remove w_sleep and w_recurse. Instead, perform checks on mutexes using the mutex's mtx_flags field. - Allow debug.witness_ddb and debug.witness_skipspin to be set from the loader. - Add Giant to the front of existing order_list entries to help ensure Giant is always first. - Add an order entry for the various proc locks. Note that this only helps keep proc in order mostly as the allproc and proctree mutexes are only obtained during a lockmgr operation on the specified mutex.
1788 lines
43 KiB
C
1788 lines
43 KiB
C
/*-
|
|
* Copyright (c) 1998 Berkeley Software Design, Inc. All rights reserved.
|
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*
|
|
* 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 $
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|
* $FreeBSD$
|
|
*/
|
|
|
|
/*
|
|
* Main Entry: witness
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|
* 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
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|
* b : public affirmation by word or example of usually
|
|
* 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
|
|
*/
|
|
|
|
#include "opt_ddb.h"
|
|
#include "opt_witness.h"
|
|
|
|
/*
|
|
* Cause non-inlined mtx_*() to be compiled.
|
|
* Must be defined early because other system headers may include mutex.h.
|
|
*/
|
|
#define _KERN_MUTEX_C_
|
|
|
|
#include <sys/param.h>
|
|
#include <sys/bus.h>
|
|
#include <sys/kernel.h>
|
|
#include <sys/malloc.h>
|
|
#include <sys/proc.h>
|
|
#include <sys/sysctl.h>
|
|
#include <sys/systm.h>
|
|
#include <sys/vmmeter.h>
|
|
#include <sys/ktr.h>
|
|
|
|
#include <machine/atomic.h>
|
|
#include <machine/bus.h>
|
|
#include <machine/clock.h>
|
|
#include <machine/cpu.h>
|
|
|
|
#include <ddb/ddb.h>
|
|
|
|
#include <vm/vm.h>
|
|
#include <vm/vm_extern.h>
|
|
|
|
#include <sys/mutex.h>
|
|
|
|
/*
|
|
* Machine independent bits of the mutex implementation
|
|
*/
|
|
|
|
#ifdef WITNESS
|
|
struct mtx_debug {
|
|
struct witness *mtxd_witness;
|
|
LIST_ENTRY(mtx) mtxd_held;
|
|
const char *mtxd_file;
|
|
int mtxd_line;
|
|
};
|
|
|
|
#define mtx_held mtx_debug->mtxd_held
|
|
#define mtx_file mtx_debug->mtxd_file
|
|
#define mtx_line mtx_debug->mtxd_line
|
|
#define mtx_witness mtx_debug->mtxd_witness
|
|
#endif /* WITNESS */
|
|
|
|
/*
|
|
* Assembly macros
|
|
*------------------------------------------------------------------------------
|
|
*/
|
|
|
|
#define _V(x) __STRING(x)
|
|
|
|
/*
|
|
* Default, unoptimized mutex micro-operations
|
|
*/
|
|
|
|
#ifndef _obtain_lock
|
|
/* Actually obtain mtx_lock */
|
|
#define _obtain_lock(mp, tid) \
|
|
atomic_cmpset_acq_ptr(&(mp)->mtx_lock, (void *)MTX_UNOWNED, (tid))
|
|
#endif
|
|
|
|
#ifndef _release_lock
|
|
/* Actually release mtx_lock */
|
|
#define _release_lock(mp, tid) \
|
|
atomic_cmpset_rel_ptr(&(mp)->mtx_lock, (tid), (void *)MTX_UNOWNED)
|
|
#endif
|
|
|
|
#ifndef _release_lock_quick
|
|
/* Actually release mtx_lock quickly assuming that we own it */
|
|
#define _release_lock_quick(mp) \
|
|
atomic_store_rel_ptr(&(mp)->mtx_lock, (void *)MTX_UNOWNED)
|
|
#endif
|
|
|
|
#ifndef _getlock_sleep
|
|
/* Get a sleep lock, deal with recursion inline. */
|
|
#define _getlock_sleep(mp, tid, type) do { \
|
|
if (!_obtain_lock(mp, tid)) { \
|
|
if (((mp)->mtx_lock & MTX_FLAGMASK) != ((uintptr_t)(tid)))\
|
|
mtx_enter_hard(mp, (type) & MTX_HARDOPTS, 0); \
|
|
else { \
|
|
atomic_set_ptr(&(mp)->mtx_lock, MTX_RECURSED); \
|
|
(mp)->mtx_recurse++; \
|
|
} \
|
|
} \
|
|
} while (0)
|
|
#endif
|
|
|
|
#ifndef _getlock_spin_block
|
|
/* Get a spin lock, handle recursion inline (as the less common case) */
|
|
#define _getlock_spin_block(mp, tid, type) do { \
|
|
u_int _mtx_intr = save_intr(); \
|
|
disable_intr(); \
|
|
if (!_obtain_lock(mp, tid)) \
|
|
mtx_enter_hard(mp, (type) & MTX_HARDOPTS, _mtx_intr); \
|
|
else \
|
|
(mp)->mtx_saveintr = _mtx_intr; \
|
|
} while (0)
|
|
#endif
|
|
|
|
#ifndef _getlock_norecurse
|
|
/*
|
|
* Get a lock without any recursion handling. Calls the hard enter function if
|
|
* we can't get it inline.
|
|
*/
|
|
#define _getlock_norecurse(mp, tid, type) do { \
|
|
if (!_obtain_lock(mp, tid)) \
|
|
mtx_enter_hard((mp), (type) & MTX_HARDOPTS, 0); \
|
|
} while (0)
|
|
#endif
|
|
|
|
#ifndef _exitlock_norecurse
|
|
/*
|
|
* Release a sleep lock assuming we haven't recursed on it, recursion is handled
|
|
* in the hard function.
|
|
*/
|
|
#define _exitlock_norecurse(mp, tid, type) do { \
|
|
if (!_release_lock(mp, tid)) \
|
|
mtx_exit_hard((mp), (type) & MTX_HARDOPTS); \
|
|
} while (0)
|
|
#endif
|
|
|
|
#ifndef _exitlock
|
|
/*
|
|
* Release a sleep lock when its likely we recursed (the code to
|
|
* deal with simple recursion is inline).
|
|
*/
|
|
#define _exitlock(mp, tid, type) do { \
|
|
if (!_release_lock(mp, tid)) { \
|
|
if ((mp)->mtx_lock & MTX_RECURSED) { \
|
|
if (--((mp)->mtx_recurse) == 0) \
|
|
atomic_clear_ptr(&(mp)->mtx_lock, \
|
|
MTX_RECURSED); \
|
|
} else { \
|
|
mtx_exit_hard((mp), (type) & MTX_HARDOPTS); \
|
|
} \
|
|
} \
|
|
} while (0)
|
|
#endif
|
|
|
|
#ifndef _exitlock_spin
|
|
/* Release a spin lock (with possible recursion). */
|
|
#define _exitlock_spin(mp) do { \
|
|
if (!mtx_recursed((mp))) { \
|
|
int _mtx_intr = (mp)->mtx_saveintr; \
|
|
\
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|
_release_lock_quick(mp); \
|
|
restore_intr(_mtx_intr); \
|
|
} else { \
|
|
(mp)->mtx_recurse--; \
|
|
} \
|
|
} while (0)
|
|
#endif
|
|
|
|
#ifdef WITNESS
|
|
static void witness_init(struct mtx *, int flag);
|
|
static void witness_destroy(struct mtx *);
|
|
static void witness_display(void(*)(const char *fmt, ...));
|
|
|
|
/* All mutexes in system (used for debug/panic) */
|
|
static struct mtx_debug all_mtx_debug = { NULL, {NULL, NULL}, NULL, 0 };
|
|
/*
|
|
* Set to 0 once mutexes have been fully initialized so that witness code can be
|
|
* safely executed.
|
|
*/
|
|
static int witness_cold = 1;
|
|
#else /* WITNESS */
|
|
|
|
/*
|
|
* flag++ is slezoid way of shutting up unused parameter warning
|
|
* in mtx_init()
|
|
*/
|
|
#define witness_init(m, flag) flag++
|
|
#define witness_destroy(m)
|
|
#define witness_try_enter(m, t, f, l)
|
|
#endif /* WITNESS */
|
|
|
|
/* All mutexes in system (used for debug/panic) */
|
|
static struct mtx all_mtx = { MTX_UNOWNED, 0, 0, 0, "All mutexes queue head",
|
|
TAILQ_HEAD_INITIALIZER(all_mtx.mtx_blocked),
|
|
{ NULL, NULL }, &all_mtx, &all_mtx,
|
|
#ifdef WITNESS
|
|
&all_mtx_debug
|
|
#else
|
|
NULL
|
|
#endif
|
|
};
|
|
|
|
static int mtx_cur_cnt;
|
|
static int mtx_max_cnt;
|
|
|
|
static void propagate_priority(struct proc *);
|
|
static void mtx_enter_hard(struct mtx *, int type, int saveintr);
|
|
static void mtx_exit_hard(struct mtx *, int type);
|
|
|
|
#define mtx_unowned(m) ((m)->mtx_lock == MTX_UNOWNED)
|
|
#define mtx_owner(m) (mtx_unowned(m) ? NULL \
|
|
: (struct proc *)((m)->mtx_lock & MTX_FLAGMASK))
|
|
|
|
#define RETIP(x) *(((uintptr_t *)(&x)) - 1)
|
|
#define SET_PRIO(p, pri) (p)->p_priority = (pri)
|
|
|
|
static void
|
|
propagate_priority(struct proc *p)
|
|
{
|
|
int pri = p->p_priority;
|
|
struct mtx *m = p->p_blocked;
|
|
|
|
mtx_assert(&sched_lock, MA_OWNED);
|
|
for (;;) {
|
|
struct proc *p1;
|
|
|
|
p = mtx_owner(m);
|
|
|
|
if (p == NULL) {
|
|
/*
|
|
* This really isn't quite right. Really
|
|
* ought to bump priority of process that
|
|
* next acquires the mutex.
|
|
*/
|
|
MPASS(m->mtx_lock == MTX_CONTESTED);
|
|
return;
|
|
}
|
|
MPASS(p->p_magic == P_MAGIC);
|
|
KASSERT(p->p_stat != SSLEEP, ("sleeping process owns a mutex"));
|
|
if (p->p_priority <= pri)
|
|
return;
|
|
|
|
/*
|
|
* Bump this process' priority.
|
|
*/
|
|
SET_PRIO(p, pri);
|
|
|
|
/*
|
|
* If lock holder is actually running, just bump priority.
|
|
*/
|
|
#ifdef SMP
|
|
/*
|
|
* For SMP, we can check the p_oncpu field to see if we are
|
|
* running.
|
|
*/
|
|
if (p->p_oncpu != 0xff) {
|
|
MPASS(p->p_stat == SRUN || p->p_stat == SZOMB);
|
|
return;
|
|
}
|
|
#else
|
|
/*
|
|
* For UP, we check to see if p is curproc (this shouldn't
|
|
* ever happen however as it would mean we are in a deadlock.)
|
|
*/
|
|
if (p == curproc) {
|
|
panic("Deadlock detected");
|
|
return;
|
|
}
|
|
#endif
|
|
/*
|
|
* If on run queue move to new run queue, and
|
|
* quit.
|
|
*/
|
|
if (p->p_stat == SRUN) {
|
|
printf("XXX: moving process %d(%s) to a new run queue\n",
|
|
p->p_pid, p->p_comm);
|
|
MPASS(p->p_blocked == NULL);
|
|
remrunqueue(p);
|
|
setrunqueue(p);
|
|
return;
|
|
}
|
|
|
|
/*
|
|
* If we aren't blocked on a mutex, we should be.
|
|
*/
|
|
KASSERT(p->p_stat == SMTX, (
|
|
"process %d(%s):%d holds %s but isn't blocked on a mutex\n",
|
|
p->p_pid, p->p_comm, p->p_stat,
|
|
m->mtx_description));
|
|
|
|
/*
|
|
* Pick up the mutex that p is blocked on.
|
|
*/
|
|
m = p->p_blocked;
|
|
MPASS(m != NULL);
|
|
|
|
printf("XXX: process %d(%s) is blocked on %s\n", p->p_pid,
|
|
p->p_comm, m->mtx_description);
|
|
/*
|
|
* Check if the proc needs to be moved up on
|
|
* the blocked chain
|
|
*/
|
|
if (p == TAILQ_FIRST(&m->mtx_blocked)) {
|
|
printf("XXX: process at head of run queue\n");
|
|
continue;
|
|
}
|
|
p1 = TAILQ_PREV(p, rq, p_procq);
|
|
if (p1->p_priority <= pri) {
|
|
printf(
|
|
"XXX: previous process %d(%s) has higher priority\n",
|
|
p->p_pid, p->p_comm);
|
|
continue;
|
|
}
|
|
|
|
/*
|
|
* Remove proc from blocked chain and determine where
|
|
* it should be moved up to. Since we know that p1 has
|
|
* a lower priority than p, we know that at least one
|
|
* process in the chain has a lower priority and that
|
|
* p1 will thus not be NULL after the loop.
|
|
*/
|
|
TAILQ_REMOVE(&m->mtx_blocked, p, p_procq);
|
|
TAILQ_FOREACH(p1, &m->mtx_blocked, p_procq) {
|
|
MPASS(p1->p_magic == P_MAGIC);
|
|
if (p1->p_priority > pri)
|
|
break;
|
|
}
|
|
MPASS(p1 != NULL);
|
|
TAILQ_INSERT_BEFORE(p1, p, p_procq);
|
|
CTR4(KTR_LOCK,
|
|
"propagate_priority: p %p moved before %p on [%p] %s",
|
|
p, p1, m, m->mtx_description);
|
|
}
|
|
}
|
|
|
|
/*
|
|
* Get lock 'm', the macro handles the easy (and most common cases) and leaves
|
|
* the slow stuff to the mtx_enter_hard() function.
|
|
*
|
|
* Note: since type is usually a constant much of this code is optimized out.
|
|
*/
|
|
void
|
|
_mtx_enter(struct mtx *mtxp, int type, const char *file, int line)
|
|
{
|
|
struct mtx *mpp = mtxp;
|
|
|
|
/* bits only valid on mtx_exit() */
|
|
MPASS4(((type) & (MTX_NORECURSE | MTX_NOSWITCH)) == 0,
|
|
STR_mtx_bad_type, file, line);
|
|
|
|
if ((type) & MTX_SPIN) {
|
|
/*
|
|
* Easy cases of spin locks:
|
|
*
|
|
* 1) We already own the lock and will simply recurse on it (if
|
|
* RLIKELY)
|
|
*
|
|
* 2) The lock is free, we just get it
|
|
*/
|
|
if ((type) & MTX_RLIKELY) {
|
|
/*
|
|
* Check for recursion, if we already have this
|
|
* lock we just bump the recursion count.
|
|
*/
|
|
if (mpp->mtx_lock == (uintptr_t)CURTHD) {
|
|
mpp->mtx_recurse++;
|
|
goto done;
|
|
}
|
|
}
|
|
|
|
if (((type) & MTX_TOPHALF) == 0) {
|
|
/*
|
|
* If an interrupt thread uses this we must block
|
|
* interrupts here.
|
|
*/
|
|
if ((type) & MTX_FIRST) {
|
|
ASS_IEN;
|
|
disable_intr();
|
|
_getlock_norecurse(mpp, CURTHD,
|
|
(type) & MTX_HARDOPTS);
|
|
} else {
|
|
_getlock_spin_block(mpp, CURTHD,
|
|
(type) & MTX_HARDOPTS);
|
|
}
|
|
} else
|
|
_getlock_norecurse(mpp, CURTHD, (type) & MTX_HARDOPTS);
|
|
} else {
|
|
/* Sleep locks */
|
|
if ((type) & MTX_RLIKELY)
|
|
_getlock_sleep(mpp, CURTHD, (type) & MTX_HARDOPTS);
|
|
else
|
|
_getlock_norecurse(mpp, CURTHD, (type) & MTX_HARDOPTS);
|
|
}
|
|
done:
|
|
WITNESS_ENTER(mpp, type, file, line);
|
|
if (((type) & MTX_QUIET) == 0)
|
|
CTR5(KTR_LOCK, STR_mtx_enter_fmt,
|
|
mpp->mtx_description, mpp, mpp->mtx_recurse, file, line);
|
|
|
|
}
|
|
|
|
/*
|
|
* Attempt to get MTX_DEF lock, return non-zero if lock acquired.
|
|
*
|
|
* XXX DOES NOT HANDLE RECURSION
|
|
*/
|
|
int
|
|
_mtx_try_enter(struct mtx *mtxp, int type, const char *file, int line)
|
|
{
|
|
struct mtx *const mpp = mtxp;
|
|
int rval;
|
|
|
|
rval = _obtain_lock(mpp, CURTHD);
|
|
#ifdef WITNESS
|
|
if (rval && mpp->mtx_witness != NULL) {
|
|
MPASS(mpp->mtx_recurse == 0);
|
|
witness_try_enter(mpp, type, file, line);
|
|
}
|
|
#endif /* WITNESS */
|
|
if (((type) & MTX_QUIET) == 0)
|
|
CTR5(KTR_LOCK, STR_mtx_try_enter_fmt,
|
|
mpp->mtx_description, mpp, rval, file, line);
|
|
|
|
return rval;
|
|
}
|
|
|
|
/*
|
|
* Release lock m.
|
|
*/
|
|
void
|
|
_mtx_exit(struct mtx *mtxp, int type, const char *file, int line)
|
|
{
|
|
struct mtx *const mpp = mtxp;
|
|
|
|
MPASS4(mtx_owned(mpp), STR_mtx_owned, file, line);
|
|
WITNESS_EXIT(mpp, type, file, line);
|
|
if (((type) & MTX_QUIET) == 0)
|
|
CTR5(KTR_LOCK, STR_mtx_exit_fmt,
|
|
mpp->mtx_description, mpp, mpp->mtx_recurse, file, line);
|
|
if ((type) & MTX_SPIN) {
|
|
if ((type) & MTX_NORECURSE) {
|
|
int mtx_intr = mpp->mtx_saveintr;
|
|
|
|
MPASS4(mpp->mtx_recurse == 0, STR_mtx_recurse,
|
|
file, line);
|
|
_release_lock_quick(mpp);
|
|
if (((type) & MTX_TOPHALF) == 0) {
|
|
if ((type) & MTX_FIRST) {
|
|
ASS_IDIS;
|
|
enable_intr();
|
|
} else
|
|
restore_intr(mtx_intr);
|
|
}
|
|
} else {
|
|
if (((type & MTX_TOPHALF) == 0) &&
|
|
(type & MTX_FIRST)) {
|
|
ASS_IDIS;
|
|
ASS_SIEN(mpp);
|
|
}
|
|
_exitlock_spin(mpp);
|
|
}
|
|
} else {
|
|
/* Handle sleep locks */
|
|
if ((type) & MTX_RLIKELY)
|
|
_exitlock(mpp, CURTHD, (type) & MTX_HARDOPTS);
|
|
else {
|
|
_exitlock_norecurse(mpp, CURTHD,
|
|
(type) & MTX_HARDOPTS);
|
|
}
|
|
}
|
|
}
|
|
|
|
void
|
|
mtx_enter_hard(struct mtx *m, int type, int saveintr)
|
|
{
|
|
struct proc *p = CURPROC;
|
|
|
|
KASSERT(p != NULL, ("curproc is NULL in mutex"));
|
|
|
|
switch (type) {
|
|
case MTX_DEF:
|
|
if ((m->mtx_lock & MTX_FLAGMASK) == (uintptr_t)p) {
|
|
m->mtx_recurse++;
|
|
atomic_set_ptr(&m->mtx_lock, MTX_RECURSED);
|
|
if ((type & MTX_QUIET) == 0)
|
|
CTR1(KTR_LOCK, "mtx_enter: %p recurse", m);
|
|
return;
|
|
}
|
|
if ((type & MTX_QUIET) == 0)
|
|
CTR3(KTR_LOCK,
|
|
"mtx_enter: %p contested (lock=%p) [%p]",
|
|
m, (void *)m->mtx_lock, (void *)RETIP(m));
|
|
|
|
/*
|
|
* Save our priority. Even though p_nativepri is protected
|
|
* by sched_lock, we don't obtain it here as it can be
|
|
* expensive. Since this is the only place p_nativepri is
|
|
* set, and since two CPUs will not be executing the same
|
|
* process concurrently, we know that no other CPU is going
|
|
* to be messing with this. Also, p_nativepri is only read
|
|
* when we are blocked on a mutex, so that can't be happening
|
|
* right now either.
|
|
*/
|
|
p->p_nativepri = p->p_priority;
|
|
while (!_obtain_lock(m, p)) {
|
|
uintptr_t v;
|
|
struct proc *p1;
|
|
|
|
mtx_enter(&sched_lock, MTX_SPIN | MTX_RLIKELY);
|
|
/*
|
|
* check if the lock has been released while
|
|
* waiting for the schedlock.
|
|
*/
|
|
if ((v = m->mtx_lock) == MTX_UNOWNED) {
|
|
mtx_exit(&sched_lock, MTX_SPIN);
|
|
continue;
|
|
}
|
|
/*
|
|
* The mutex was marked contested on release. This
|
|
* means that there are processes blocked on it.
|
|
*/
|
|
if (v == MTX_CONTESTED) {
|
|
p1 = TAILQ_FIRST(&m->mtx_blocked);
|
|
KASSERT(p1 != NULL, ("contested mutex has no contesters"));
|
|
KASSERT(p != NULL, ("curproc is NULL for contested mutex"));
|
|
m->mtx_lock = (uintptr_t)p | MTX_CONTESTED;
|
|
if (p1->p_priority < p->p_priority) {
|
|
SET_PRIO(p, p1->p_priority);
|
|
}
|
|
mtx_exit(&sched_lock, MTX_SPIN);
|
|
return;
|
|
}
|
|
/*
|
|
* If the mutex isn't already contested and
|
|
* a failure occurs setting the contested bit the
|
|
* mutex was either release or the
|
|
* state of the RECURSION bit changed.
|
|
*/
|
|
if ((v & MTX_CONTESTED) == 0 &&
|
|
!atomic_cmpset_ptr(&m->mtx_lock, (void *)v,
|
|
(void *)(v | MTX_CONTESTED))) {
|
|
mtx_exit(&sched_lock, MTX_SPIN);
|
|
continue;
|
|
}
|
|
|
|
/* We definitely have to sleep for this lock */
|
|
mtx_assert(m, MA_NOTOWNED);
|
|
|
|
#ifdef notyet
|
|
/*
|
|
* If we're borrowing an interrupted thread's VM
|
|
* context must clean up before going to sleep.
|
|
*/
|
|
if (p->p_flag & (P_ITHD | P_SITHD)) {
|
|
ithd_t *it = (ithd_t *)p;
|
|
|
|
if (it->it_interrupted) {
|
|
if ((type & MTX_QUIET) == 0)
|
|
CTR2(KTR_LOCK,
|
|
"mtx_enter: 0x%x interrupted 0x%x",
|
|
it, it->it_interrupted);
|
|
intr_thd_fixup(it);
|
|
}
|
|
}
|
|
#endif
|
|
|
|
/* Put us on the list of procs blocked on this mutex */
|
|
if (TAILQ_EMPTY(&m->mtx_blocked)) {
|
|
p1 = (struct proc *)(m->mtx_lock &
|
|
MTX_FLAGMASK);
|
|
LIST_INSERT_HEAD(&p1->p_contested, m,
|
|
mtx_contested);
|
|
TAILQ_INSERT_TAIL(&m->mtx_blocked, p, p_procq);
|
|
} else {
|
|
TAILQ_FOREACH(p1, &m->mtx_blocked, p_procq)
|
|
if (p1->p_priority > p->p_priority)
|
|
break;
|
|
if (p1)
|
|
TAILQ_INSERT_BEFORE(p1, p, p_procq);
|
|
else
|
|
TAILQ_INSERT_TAIL(&m->mtx_blocked, p,
|
|
p_procq);
|
|
}
|
|
|
|
p->p_blocked = m; /* Who we're blocked on */
|
|
p->p_mtxname = m->mtx_description;
|
|
p->p_stat = SMTX;
|
|
#if 0
|
|
propagate_priority(p);
|
|
#endif
|
|
if ((type & MTX_QUIET) == 0)
|
|
CTR3(KTR_LOCK,
|
|
"mtx_enter: p %p blocked on [%p] %s",
|
|
p, m, m->mtx_description);
|
|
mi_switch();
|
|
if ((type & MTX_QUIET) == 0)
|
|
CTR3(KTR_LOCK,
|
|
"mtx_enter: p %p free from blocked on [%p] %s",
|
|
p, m, m->mtx_description);
|
|
mtx_exit(&sched_lock, MTX_SPIN);
|
|
}
|
|
return;
|
|
case MTX_SPIN:
|
|
case MTX_SPIN | MTX_FIRST:
|
|
case MTX_SPIN | MTX_TOPHALF:
|
|
{
|
|
int i = 0;
|
|
|
|
if (m->mtx_lock == (uintptr_t)p) {
|
|
m->mtx_recurse++;
|
|
return;
|
|
}
|
|
if ((type & MTX_QUIET) == 0)
|
|
CTR1(KTR_LOCK, "mtx_enter: %p spinning", m);
|
|
for (;;) {
|
|
if (_obtain_lock(m, p))
|
|
break;
|
|
while (m->mtx_lock != MTX_UNOWNED) {
|
|
if (i++ < 1000000)
|
|
continue;
|
|
if (i++ < 6000000)
|
|
DELAY (1);
|
|
#ifdef DDB
|
|
else if (!db_active)
|
|
#else
|
|
else
|
|
#endif
|
|
panic(
|
|
"spin lock %s held by %p for > 5 seconds",
|
|
m->mtx_description,
|
|
(void *)m->mtx_lock);
|
|
}
|
|
}
|
|
|
|
#ifdef MUTEX_DEBUG
|
|
if (type != MTX_SPIN)
|
|
m->mtx_saveintr = 0xbeefface;
|
|
else
|
|
#endif
|
|
m->mtx_saveintr = saveintr;
|
|
if ((type & MTX_QUIET) == 0)
|
|
CTR1(KTR_LOCK, "mtx_enter: %p spin done", m);
|
|
return;
|
|
}
|
|
}
|
|
}
|
|
|
|
void
|
|
mtx_exit_hard(struct mtx *m, int type)
|
|
{
|
|
struct proc *p, *p1;
|
|
struct mtx *m1;
|
|
int pri;
|
|
|
|
p = CURPROC;
|
|
switch (type) {
|
|
case MTX_DEF:
|
|
case MTX_DEF | MTX_NOSWITCH:
|
|
if (mtx_recursed(m)) {
|
|
if (--(m->mtx_recurse) == 0)
|
|
atomic_clear_ptr(&m->mtx_lock, MTX_RECURSED);
|
|
if ((type & MTX_QUIET) == 0)
|
|
CTR1(KTR_LOCK, "mtx_exit: %p unrecurse", m);
|
|
return;
|
|
}
|
|
mtx_enter(&sched_lock, MTX_SPIN);
|
|
if ((type & MTX_QUIET) == 0)
|
|
CTR1(KTR_LOCK, "mtx_exit: %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 ((type & MTX_QUIET) == 0)
|
|
CTR1(KTR_LOCK, "mtx_exit: %p not held", m);
|
|
} else
|
|
atomic_store_rel_ptr(&m->mtx_lock,
|
|
(void *)MTX_CONTESTED);
|
|
pri = MAXPRI;
|
|
LIST_FOREACH(m1, &p->p_contested, mtx_contested) {
|
|
int cp = TAILQ_FIRST(&m1->mtx_blocked)->p_priority;
|
|
if (cp < pri)
|
|
pri = cp;
|
|
}
|
|
if (pri > p->p_nativepri)
|
|
pri = p->p_nativepri;
|
|
SET_PRIO(p, pri);
|
|
if ((type & MTX_QUIET) == 0)
|
|
CTR2(KTR_LOCK,
|
|
"mtx_exit: %p contested setrunqueue %p", m, p1);
|
|
p1->p_blocked = NULL;
|
|
p1->p_mtxname = NULL;
|
|
p1->p_stat = SRUN;
|
|
setrunqueue(p1);
|
|
if ((type & MTX_NOSWITCH) == 0 && p1->p_priority < pri) {
|
|
#ifdef notyet
|
|
if (p->p_flag & (P_ITHD | P_SITHD)) {
|
|
ithd_t *it = (ithd_t *)p;
|
|
|
|
if (it->it_interrupted) {
|
|
if ((type & MTX_QUIET) == 0)
|
|
CTR2(KTR_LOCK,
|
|
"mtx_exit: 0x%x interruped 0x%x",
|
|
it, it->it_interrupted);
|
|
intr_thd_fixup(it);
|
|
}
|
|
}
|
|
#endif
|
|
setrunqueue(p);
|
|
if ((type & MTX_QUIET) == 0)
|
|
CTR2(KTR_LOCK,
|
|
"mtx_exit: %p switching out lock=%p",
|
|
m, (void *)m->mtx_lock);
|
|
mi_switch();
|
|
if ((type & MTX_QUIET) == 0)
|
|
CTR2(KTR_LOCK,
|
|
"mtx_exit: %p resuming lock=%p",
|
|
m, (void *)m->mtx_lock);
|
|
}
|
|
mtx_exit(&sched_lock, MTX_SPIN);
|
|
break;
|
|
case MTX_SPIN:
|
|
case MTX_SPIN | MTX_FIRST:
|
|
if (mtx_recursed(m)) {
|
|
m->mtx_recurse--;
|
|
return;
|
|
}
|
|
MPASS(mtx_owned(m));
|
|
_release_lock_quick(m);
|
|
if (type & MTX_FIRST)
|
|
enable_intr(); /* XXX is this kosher? */
|
|
else {
|
|
MPASS(m->mtx_saveintr != 0xbeefface);
|
|
restore_intr(m->mtx_saveintr);
|
|
}
|
|
break;
|
|
case MTX_SPIN | MTX_TOPHALF:
|
|
if (mtx_recursed(m)) {
|
|
m->mtx_recurse--;
|
|
return;
|
|
}
|
|
MPASS(mtx_owned(m));
|
|
_release_lock_quick(m);
|
|
break;
|
|
default:
|
|
panic("mtx_exit_hard: unsupported type 0x%x\n", type);
|
|
}
|
|
}
|
|
|
|
#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
|
|
|
|
#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_enter(&all_mtx, MTX_DEF);
|
|
/*
|
|
* 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_exit(&all_mtx, MTX_DEF);
|
|
return (retval);
|
|
}
|
|
#endif
|
|
|
|
void
|
|
mtx_init(struct mtx *m, const char *t, int flag)
|
|
{
|
|
if ((flag & MTX_QUIET) == 0)
|
|
CTR2(KTR_LOCK, "mtx_init %p (%s)", m, t);
|
|
#ifdef MUTEX_DEBUG
|
|
if (mtx_validate(m, MV_INIT)) /* diagnostic and error correction */
|
|
return;
|
|
#endif
|
|
|
|
bzero((void *)m, sizeof *m);
|
|
TAILQ_INIT(&m->mtx_blocked);
|
|
#ifdef WITNESS
|
|
if (!witness_cold) {
|
|
/* XXX - should not use DEVBUF */
|
|
m->mtx_debug = malloc(sizeof(struct mtx_debug),
|
|
M_DEVBUF, M_NOWAIT | M_ZERO);
|
|
MPASS(m->mtx_debug != NULL);
|
|
}
|
|
#endif
|
|
m->mtx_description = t;
|
|
|
|
m->mtx_flags = flag;
|
|
m->mtx_lock = MTX_UNOWNED;
|
|
/* Put on all mutex queue */
|
|
mtx_enter(&all_mtx, MTX_DEF);
|
|
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_exit(&all_mtx, MTX_DEF);
|
|
#ifdef WITNESS
|
|
if (!witness_cold)
|
|
witness_init(m, flag);
|
|
#endif
|
|
}
|
|
|
|
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);
|
|
}
|
|
mtx_validate(m, MV_DESTROY); /* diagnostic */
|
|
#endif
|
|
|
|
#ifdef WITNESS
|
|
if (m->mtx_witness)
|
|
witness_destroy(m);
|
|
#endif /* WITNESS */
|
|
|
|
/* Remove from the all mutex queue */
|
|
mtx_enter(&all_mtx, MTX_DEF);
|
|
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_DEVBUF);
|
|
m->mtx_debug = NULL;
|
|
#endif
|
|
mtx_cur_cnt--;
|
|
mtx_exit(&all_mtx, MTX_DEF);
|
|
}
|
|
|
|
/*
|
|
* The non-inlined versions of the mtx_*() functions are always built (above),
|
|
* but the witness code depends on the WITNESS kernel option being specified.
|
|
*/
|
|
|
|
#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_exit(&Giant, MTX_DEF);
|
|
mtx_assert(&Giant, MA_NOTOWNED);
|
|
mtx_enter(&all_mtx, MTX_DEF);
|
|
|
|
/* Iterate through all mutexes and finish up mutex initialization. */
|
|
for (mp = all_mtx.mtx_next; mp != &all_mtx; mp = mp->mtx_next) {
|
|
|
|
/* XXX - should not use DEVBUF */
|
|
mp->mtx_debug = malloc(sizeof(struct mtx_debug),
|
|
M_DEVBUF, M_NOWAIT | M_ZERO);
|
|
MPASS(mp->mtx_debug != NULL);
|
|
|
|
witness_init(mp, mp->mtx_flags);
|
|
}
|
|
mtx_exit(&all_mtx, MTX_DEF);
|
|
|
|
/* Mark the witness code as being ready for use. */
|
|
atomic_store_rel_int(&witness_cold, 0);
|
|
|
|
mtx_enter(&Giant, MTX_DEF);
|
|
}
|
|
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,
|
|
"");
|
|
|
|
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];
|
|
|
|
static struct witness *enroll __P((const char *description, int flag));
|
|
static int itismychild __P((struct witness *parent, struct witness *child));
|
|
static void removechild __P((struct witness *parent, struct witness *child));
|
|
static int isitmychild __P((struct witness *parent, struct witness *child));
|
|
static int isitmydescendant __P((struct witness *parent, struct witness *child));
|
|
static int dup_ok __P((struct witness *));
|
|
static int blessed __P((struct witness *, struct witness *));
|
|
static void witness_displaydescendants
|
|
__P((void(*)(const char *fmt, ...), struct witness *));
|
|
static void witness_leveldescendents __P((struct witness *parent, int level));
|
|
static void witness_levelall __P((void));
|
|
static struct witness * witness_get __P((void));
|
|
static void witness_free __P((struct witness *m));
|
|
|
|
|
|
static char *ignore_list[] = {
|
|
"witness lock",
|
|
NULL
|
|
};
|
|
|
|
static char *spin_order_list[] = {
|
|
"sio",
|
|
"sched lock",
|
|
#ifdef __i386__
|
|
"clk",
|
|
#endif
|
|
"callout",
|
|
/*
|
|
* leaf locks
|
|
*/
|
|
NULL
|
|
};
|
|
|
|
static char *order_list[] = {
|
|
"Giant", "uidinfo hash", "uidinfo struct", NULL,
|
|
"Giant", "proctree", "allproc", "process lock", 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;
|
|
for ((m1 = LIST_FIRST(&p->p_heldmtx)); m1 != NULL;
|
|
m1 = LIST_NEXT(m1, 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;
|
|
|
|
KASSERT(!witness_cold, ("%s: witness_cold\n", __FUNCTION__));
|
|
witness_levelall();
|
|
|
|
for (w = w_all; w; w = w->w_next) {
|
|
if (w->w_file == NULL)
|
|
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);
|
|
}
|
|
prnt("\nMutex 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_enter(&w_mtx, MTX_SPIN | MTX_QUIET);
|
|
i = PCPU_GET(witness_spin_check);
|
|
if (i != 0 && w->w_level < i) {
|
|
mtx_exit(&w_mtx, MTX_SPIN | 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_exit(&w_mtx, MTX_SPIN | 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_enter() 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_enter(&w_mtx, MTX_SPIN | MTX_QUIET);
|
|
/*
|
|
* If we have a known higher number just say ok
|
|
*/
|
|
if (witness_watch > 1 && w->w_level > w1->w_level) {
|
|
mtx_exit(&w_mtx, MTX_SPIN | MTX_QUIET);
|
|
goto out;
|
|
}
|
|
if (isitmydescendant(m1->mtx_witness, w)) {
|
|
mtx_exit(&w_mtx, MTX_SPIN | 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_exit(&w_mtx, MTX_SPIN | 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_exit(&w_mtx, MTX_SPIN | 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_enter(&w_mtx, MTX_SPIN | MTX_QUIET);
|
|
PCPU_SET(witness_spin_check,
|
|
PCPU_GET(witness_spin_check) | w->w_level);
|
|
mtx_exit(&w_mtx, MTX_SPIN | 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_enter(&w_mtx, MTX_SPIN | MTX_QUIET);
|
|
PCPU_SET(witness_spin_check,
|
|
PCPU_GET(witness_spin_check) & ~w->w_level);
|
|
mtx_exit(&w_mtx, MTX_SPIN | 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_exit() 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;
|
|
for ((m = LIST_FIRST(&p->p_heldmtx)); m != NULL;
|
|
m = LIST_NEXT(m, mtx_held)) {
|
|
if (m == mtx)
|
|
continue;
|
|
for (sleep = sleep_list; *sleep!= NULL; sleep++)
|
|
if (strcmp(m->mtx_description, *sleep) == 0)
|
|
goto next;
|
|
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_enter(&w_mtx, MTX_SPIN | MTX_QUIET);
|
|
for (w = w_all; w; w = w->w_next) {
|
|
if (strcmp(description, w->w_description) == 0) {
|
|
mtx_exit(&w_mtx, MTX_SPIN | MTX_QUIET);
|
|
return (w);
|
|
}
|
|
}
|
|
if ((w = witness_get()) == NULL)
|
|
return (NULL);
|
|
w->w_next = w_all;
|
|
w_all = w;
|
|
w->w_description = description;
|
|
mtx_exit(&w_mtx, MTX_SPIN | 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 = 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", parent->w_file);
|
|
#ifndef W_USE_WHERE
|
|
prnt(":%d", parent->w_line);
|
|
#endif
|
|
prnt("\n");
|
|
}
|
|
|
|
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_exit(&w_mtx, MTX_SPIN | 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;
|
|
for ((m = LIST_FIRST(&p->p_heldmtx)); m != NULL;
|
|
m = LIST_NEXT(m, 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);
|
|
}
|
|
|
|
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 */
|