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authorPeter Zijlstra <a.p.zijlstra@chello.nl>2006-11-06 02:52:10 -0500
committerLinus Torvalds <torvalds@g5.osdl.org>2006-11-06 04:46:23 -0500
commit64efade11cddc4237c1b95ea4ca18af122a7e19e (patch)
tree0a98f64b43f1b1199a45bcdff07743afbb526989 /kernel
parente5b9a335fd2180c6db1bcc4b24e83aff7481ebe3 (diff)
[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>
Diffstat (limited to 'kernel')
-rw-r--r--kernel/delayacct.c15
1 files changed, 9 insertions, 6 deletions
diff --git a/kernel/delayacct.c b/kernel/delayacct.c
index 36752f124c6a..66a0ea48751d 100644
--- a/kernel/delayacct.c
+++ b/kernel/delayacct.c
@@ -66,6 +66,7 @@ static void delayacct_end(struct timespec *start, struct timespec *end,
66{ 66{
67 struct timespec ts; 67 struct timespec ts;
68 s64 ns; 68 s64 ns;
69 unsigned long flags;
69 70
70 do_posix_clock_monotonic_gettime(end); 71 do_posix_clock_monotonic_gettime(end);
71 ts = timespec_sub(*end, *start); 72 ts = timespec_sub(*end, *start);
@@ -73,10 +74,10 @@ static void delayacct_end(struct timespec *start, struct timespec *end,
73 if (ns < 0) 74 if (ns < 0)
74 return; 75 return;
75 76
76 spin_lock(&current->delays->lock); 77 spin_lock_irqsave(&current->delays->lock, flags);
77 *total += ns; 78 *total += ns;
78 (*count)++; 79 (*count)++;
79 spin_unlock(&current->delays->lock); 80 spin_unlock_irqrestore(&current->delays->lock, flags);
80} 81}
81 82
82void __delayacct_blkio_start(void) 83void __delayacct_blkio_start(void)
@@ -104,6 +105,7 @@ int __delayacct_add_tsk(struct taskstats *d, struct task_struct *tsk)
104 s64 tmp; 105 s64 tmp;
105 struct timespec ts; 106 struct timespec ts;
106 unsigned long t1,t2,t3; 107 unsigned long t1,t2,t3;
108 unsigned long flags;
107 109
108 /* Though tsk->delays accessed later, early exit avoids 110 /* Though tsk->delays accessed later, early exit avoids
109 * unnecessary returning of other data 111 * unnecessary returning of other data
@@ -136,14 +138,14 @@ int __delayacct_add_tsk(struct taskstats *d, struct task_struct *tsk)
136 138
137 /* zero XXX_total, non-zero XXX_count implies XXX stat overflowed */ 139 /* zero XXX_total, non-zero XXX_count implies XXX stat overflowed */
138 140
139 spin_lock(&tsk->delays->lock); 141 spin_lock_irqsave(&tsk->delays->lock, flags);
140 tmp = d->blkio_delay_total + tsk->delays->blkio_delay; 142 tmp = d->blkio_delay_total + tsk->delays->blkio_delay;
141 d->blkio_delay_total = (tmp < d->blkio_delay_total) ? 0 : tmp; 143 d->blkio_delay_total = (tmp < d->blkio_delay_total) ? 0 : tmp;
142 tmp = d->swapin_delay_total + tsk->delays->swapin_delay; 144 tmp = d->swapin_delay_total + tsk->delays->swapin_delay;
143 d->swapin_delay_total = (tmp < d->swapin_delay_total) ? 0 : tmp; 145 d->swapin_delay_total = (tmp < d->swapin_delay_total) ? 0 : tmp;
144 d->blkio_count += tsk->delays->blkio_count; 146 d->blkio_count += tsk->delays->blkio_count;
145 d->swapin_count += tsk->delays->swapin_count; 147 d->swapin_count += tsk->delays->swapin_count;
146 spin_unlock(&tsk->delays->lock); 148 spin_unlock_irqrestore(&tsk->delays->lock, flags);
147 149
148done: 150done:
149 return 0; 151 return 0;
@@ -152,11 +154,12 @@ done:
152__u64 __delayacct_blkio_ticks(struct task_struct *tsk) 154__u64 __delayacct_blkio_ticks(struct task_struct *tsk)
153{ 155{
154 __u64 ret; 156 __u64 ret;
157 unsigned long flags;
155 158
156 spin_lock(&tsk->delays->lock); 159 spin_lock_irqsave(&tsk->delays->lock, flags);
157 ret = nsec_to_clock_t(tsk->delays->blkio_delay + 160 ret = nsec_to_clock_t(tsk->delays->blkio_delay +
158 tsk->delays->swapin_delay); 161 tsk->delays->swapin_delay);
159 spin_unlock(&tsk->delays->lock); 162 spin_unlock_irqrestore(&tsk->delays->lock, flags);
160 return ret; 163 return ret;
161} 164}
162 165