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Be more careful with sched_lock in the SIGINFO handler. Specifically, do

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not hold sched_lock while calling ttyprintf().  If we are on a serial
console, then ttyprintf() will end up getting the sio lock, resulting in
a lock order violation.

Noticed by:	des
This commit is contained in:
jhb 2001-01-20 02:04:44 +00:00
parent 56b0811452
commit acf5a8d2d2
1 changed files with 21 additions and 10 deletions
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31
sys/kern/tty.c
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@ -2234,6 +2234,8 @@ ttyinfo(tp)
register struct proc *p, *pick;
struct timeval utime, stime;
int tmp;
const char *s;
long l;
if (ttycheckoutq(tp,0) == 0)
return;
@ -2255,11 +2257,14 @@ ttyinfo(tp)
pick = p;
mtx_enter(&sched_lock, MTX_SPIN);
s = pick->p_stat == SRUN ? "running" :
pick->p_wmesg ? pick->p_wmesg : "iowait";
mtx_exit(&sched_lock, MTX_SPIN);
ttyprintf(tp, " cmd: %s %d [%s] ", pick->p_comm, pick->p_pid,
pick->p_stat == SRUN ? "running" :
pick->p_wmesg ? pick->p_wmesg : "iowait");
s);
mtx_enter(&sched_lock, MTX_SPIN);
if (pick->p_flag & P_INMEM) {
mtx_exit(&sched_lock, MTX_SPIN);
calcru(pick, &utime, &stime, NULL);
/* Print user time. */
@ -2269,17 +2274,23 @@ ttyinfo(tp)
/* Print system time. */
ttyprintf(tp, "%ld.%02lds ",
stime.tv_sec, stime.tv_usec / 10000);
} else
} else {
mtx_exit(&sched_lock, MTX_SPIN);
ttyprintf(tp, "?.??u ?.??s ");
}
/* Print percentage cpu, resident set size. */
mtx_enter(&sched_lock, MTX_SPIN);
tmp = (pick->p_pctcpu * 10000 + FSCALE / 2) >> FSHIFT;
ttyprintf(tp, "%d%% %ldk\n",
tmp / 100,
pick->p_stat == SIDL || pick->p_stat == SWAIT ||
pick->p_stat == SZOMB ? 0 :
(long)pgtok(vmspace_resident_count(pick->p_vmspace)));
mtx_exit(&sched_lock, MTX_SPIN);
if (pick->p_stat == SIDL || pick->p_stat == SWAIT ||
pick->p_stat == SZOMB) {
mtx_exit(&sched_lock, MTX_SPIN);
l = 0;
} else {
mtx_exit(&sched_lock, MTX_SPIN);
l = pgtok(vmspace_resident_count(pick->p_vmspace));
}
ttyprintf(tp, "%d%% %ldk\n", tmp / 100, l);
}
tp->t_rocount = 0; /* so pending input will be retyped if BS */
}