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authorPeter Zijlstra <a.p.zijlstra@chello.nl>2006-11-05 23:52:10 -0800
committerLinus Torvalds <torvalds@g5.osdl.org>2006-11-06 01:46:23 -0800
commit64efade11cddc4237c1b95ea4ca18af122a7e19e (patch)
tree0a98f64b43f1b1199a45bcdff07743afbb526989
parente5b9a335fd2180c6db1bcc4b24e83aff7481ebe3 (diff)
downloadlinux-2.6.34-ux500-64efade11cddc4237c1b95ea4ca18af122a7e19e.tar.gz
[PATCH] lockdep: fix delayacct locking bug
Make the delayacct lock irqsave; this avoids the possible deadlock where an interrupt is taken while holding the delayacct lock which needs to take the delayacct lock. Signed-off-by: Peter Zijlstra <a.p.zijlstra@chello.nl> Acked-by: Oleg Nesterov <oleg@tv-sign.ru> Cc: Balbir Singh <balbir@in.ibm.com> Cc: Shailabh Nagar <nagar@watson.ibm.com> Signed-off-by: Andrew Morton <akpm@osdl.org> Signed-off-by: Linus Torvalds <torvalds@osdl.org>
-rw-r--r--kernel/delayacct.c15
1 files changed, 9 insertions, 6 deletions
diff --git a/kernel/delayacct.c b/kernel/delayacct.c
index 36752f124c6..66a0ea48751 100644
--- a/kernel/delayacct.c
+++ b/kernel/delayacct.c
@@ -66,6 +66,7 @@ static void delayacct_end(struct timespec *start, struct timespec *end,
{
struct timespec ts;
s64 ns;
+ unsigned long flags;
do_posix_clock_monotonic_gettime(end);
ts = timespec_sub(*end, *start);
@@ -73,10 +74,10 @@ static void delayacct_end(struct timespec *start, struct timespec *end,
if (ns < 0)
return;
- spin_lock(&current->delays->lock);
+ spin_lock_irqsave(&current->delays->lock, flags);
*total += ns;
(*count)++;
- spin_unlock(&current->delays->lock);
+ spin_unlock_irqrestore(&current->delays->lock, flags);
}
void __delayacct_blkio_start(void)
@@ -104,6 +105,7 @@ int __delayacct_add_tsk(struct taskstats *d, struct task_struct *tsk)
s64 tmp;
struct timespec ts;
unsigned long t1,t2,t3;
+ unsigned long flags;
/* Though tsk->delays accessed later, early exit avoids
* unnecessary returning of other data
@@ -136,14 +138,14 @@ int __delayacct_add_tsk(struct taskstats *d, struct task_struct *tsk)
/* zero XXX_total, non-zero XXX_count implies XXX stat overflowed */
- spin_lock(&tsk->delays->lock);
+ spin_lock_irqsave(&tsk->delays->lock, flags);
tmp = d->blkio_delay_total + tsk->delays->blkio_delay;
d->blkio_delay_total = (tmp < d->blkio_delay_total) ? 0 : tmp;
tmp = d->swapin_delay_total + tsk->delays->swapin_delay;
d->swapin_delay_total = (tmp < d->swapin_delay_total) ? 0 : tmp;
d->blkio_count += tsk->delays->blkio_count;
d->swapin_count += tsk->delays->swapin_count;
- spin_unlock(&tsk->delays->lock);
+ spin_unlock_irqrestore(&tsk->delays->lock, flags);
done:
return 0;
@@ -152,11 +154,12 @@ done:
__u64 __delayacct_blkio_ticks(struct task_struct *tsk)
{
__u64 ret;
+ unsigned long flags;
- spin_lock(&tsk->delays->lock);
+ spin_lock_irqsave(&tsk->delays->lock, flags);
ret = nsec_to_clock_t(tsk->delays->blkio_delay +
tsk->delays->swapin_delay);
- spin_unlock(&tsk->delays->lock);
+ spin_unlock_irqrestore(&tsk->delays->lock, flags);
return ret;
}