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There's a locking order issue with the scheduler and the callwheel locks 

as ltsleep() may call callout_reset() with the scheduler lock held.
So, prevent interrupts that may take the scheduler lock while holding
the callwheel lock.
This commit is contained in:
pk 2003-01-27 22:38:24 +00:00
parent ac44af9a88
commit 5e14aa69a8
1 changed files with 7 additions and 6 deletions
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13
sys/kern/kern_clock.c
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@ -1,4 +1,4 @@
/* $NetBSD: kern_clock.c,v 1.82 2003/01/18 10:06:24 thorpej Exp $ */
/* $NetBSD: kern_clock.c,v 1.83 2003/01/27 22:38:24 pk Exp $ */
/*-
* Copyright (c) 2000 The NetBSD Foundation, Inc.
@ -78,7 +78,7 @@
*/
#include <sys/cdefs.h>
__KERNEL_RCSID(0, "$NetBSD: kern_clock.c,v 1.82 2003/01/18 10:06:24 thorpej Exp $");
__KERNEL_RCSID(0, "$NetBSD: kern_clock.c,v 1.83 2003/01/27 22:38:24 pk Exp $");
#include "opt_callout.h"
#include "opt_ntp.h"
@ -390,7 +390,7 @@ struct simplelock callwheel_slock;
#define CALLWHEEL_LOCK(s) \
do { \
s = splclock(); \
s = splsched(); \
simple_lock(&callwheel_slock); \
} while (/*CONSTCOND*/ 0)
@ -527,6 +527,7 @@ hardclock(struct clockframe *frame)
extern long timedelta;
struct cpu_info *ci = curcpu();
struct ptimer *pt;
int s;
#ifdef NTP
int time_update;
int ltemp;
@ -890,10 +891,10 @@ hardclock(struct clockframe *frame)
* Process callouts at a very low cpu priority, so we don't keep the
* relatively high clock interrupt priority any longer than necessary.
*/
simple_lock(&callwheel_slock); /* already at splclock() */
CALLWHEEL_LOCK(s);
hardclock_ticks++;
if (! TAILQ_EMPTY(&callwheel[hardclock_ticks & callwheelmask].cq_q)) {
simple_unlock(&callwheel_slock);
CALLWHEEL_UNLOCK(s);
if (CLKF_BASEPRI(frame)) {
/*
* Save the overhead of a software interrupt;
@ -919,7 +920,7 @@ hardclock(struct clockframe *frame)
(softclock_ticks + 1) == hardclock_ticks) {
softclock_ticks++;
}
simple_unlock(&callwheel_slock);
CALLWHEEL_UNLOCK(s);
}
/*