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Code Issues Releases Activity

CURSIG() calls functions that acquire sleep mutexes, so it is not a good

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idea to be holding the sched_lock while we are calling it.  As such,
release sched_lock before calling CURSIG() in msleep() and mawait() and
reacquire it after CURSIG() returns.

Submitted by:	witness
This commit is contained in:
John Baldwin 2000-11-16 01:07:19 +00:00
parent 930a65fe47
commit 95de685572
Notes: svn2git 2020-12-20 02:59:44 +00:00 
svn path=/head/; revision=68804
1 changed files with 12 additions and 3 deletions
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15
sys/kern/kern_synch.c
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@ -477,12 +477,15 @@ msleep(ident, mtx, priority, wmesg, timo)
"msleep caught: proc %p (pid %d, %s), schedlock %p",
p, p->p_pid, p->p_comm, (void *) sched_lock.mtx_lock);
p->p_flag |= P_SINTR;
mtx_exit(&sched_lock, MTX_SPIN);
if ((sig = CURSIG(p))) {
mtx_enter(&sched_lock, MTX_SPIN);
if (p->p_wchan)
unsleep(p);
p->p_stat = SRUN;
goto resume;
}
mtx_enter(&sched_lock, MTX_SPIN);
if (p->p_wchan == 0) {
catch = 0;
goto resume;
@ -507,10 +510,13 @@ msleep(ident, mtx, priority, wmesg, timo)
ktrcsw(p->p_tracep, 0, 0);
#endif
rval = EWOULDBLOCK;
mtx_exit(&sched_lock, MTX_SPIN);
goto out;
}
} else if (timo)
untimeout(endtsleep, (void *)p, thandle);
mtx_exit(&sched_lock, MTX_SPIN);
if (catch && (sig != 0 || (sig = CURSIG(p)))) {
#ifdef KTRACE
if (KTRPOINT(p, KTR_CSW))
@ -523,7 +529,6 @@ msleep(ident, mtx, priority, wmesg, timo)
goto out;
}
out:
mtx_exit(&sched_lock, MTX_SPIN);
#ifdef KTRACE
if (KTRPOINT(p, KTR_CSW))
ktrcsw(p->p_tracep, 0, 0);
@ -643,12 +648,15 @@ mawait(struct mtx *mtx, int priority, int timo)
if (catch) {
p->p_flag |= P_SINTR;
mtx_exit(&sched_lock, MTX_SPIN);
if ((sig = CURSIG(p))) {
mtx_enter(&sched_lock, MTX_SPIN);
if (p->p_wchan)
unsleep(p);
p->p_stat = SRUN;
goto resume;
}
mtx_enter(&sched_lock, MTX_SPIN);
if (p->p_wchan == NULL) {
catch = 0;
goto resume;
@ -674,6 +682,8 @@ mawait(struct mtx *mtx, int priority, int timo)
}
} else if (timo)
untimeout(endtsleep, (void *)p, thandle);
mtx_exit(&sched_lock, MTX_SPIN);
if (catch && (sig != 0 || (sig = CURSIG(p)))) {
#ifdef KTRACE
if (KTRPOINT(p, KTR_CSW))
@ -700,6 +710,7 @@ mawait(struct mtx *mtx, int priority, int timo)
p->p_stats->p_ru.ru_nvcsw++;
mi_switch();
}
mtx_exit(&sched_lock, MTX_SPIN);
splx(s);
}
@ -712,8 +723,6 @@ mawait(struct mtx *mtx, int priority, int timo)
p->p_asleep.as_priority = 0;
out:
mtx_exit(&sched_lock, MTX_SPIN);
if (mtx != NULL) {
mtx_enter(mtx, MTX_DEF);
WITNESS_RESTORE(mtx, mtx);