diff options
| author | Gautham R Shenoy <ego@in.ibm.com> | 2007-10-18 23:40:47 -0700 |
|---|---|---|
| committer | Linus Torvalds <torvalds@woody.linux-foundation.org> | 2007-10-19 11:53:44 -0700 |
| commit | d2b20b11547cefc89d6c81937e81afaf3c62808b (patch) | |
| tree | 50a6c8e1d86c38fff417907d821eec0e0731e1a5 /lib | |
| parent | 73e753a50dcac7d6d4fa8b9552203ef544a70d77 (diff) | |
| download | lwn-d2b20b11547cefc89d6c81937e81afaf3c62808b.tar.gz lwn-d2b20b11547cefc89d6c81937e81afaf3c62808b.zip | |
Add irq protection in the percpu-counters cpu-hotplug-callback path
Some of the per-cpu counters and thus their locks are accessed from IRQ
contexts. This can cause a deadlock if it interrupts a cpu-offline thread
which is transferring a dead-cpu's counts to the global counter.
Add appropriate IRQ protection in the cpu-hotplug callback path.
Signed-off-by: Gautham R Shenoy <ego@in.ibm.com>
Cc: KAMEZAWA Hiroyuki <kamezawa.hiroyu@jp.fujitsu.com>
Signed-off-by: Andrew Morton <akpm@linux-foundation.org>
Signed-off-by: Linus Torvalds <torvalds@linux-foundation.org>
Diffstat (limited to 'lib')
| -rw-r--r-- | lib/percpu_counter.c | 5 |
1 files changed, 3 insertions, 2 deletions
diff --git a/lib/percpu_counter.c b/lib/percpu_counter.c index 9659eabffc31..393a0e915c23 100644 --- a/lib/percpu_counter.c +++ b/lib/percpu_counter.c @@ -124,12 +124,13 @@ static int __cpuinit percpu_counter_hotcpu_callback(struct notifier_block *nb, mutex_lock(&percpu_counters_lock); list_for_each_entry(fbc, &percpu_counters, list) { s32 *pcount; + unsigned long flags; - spin_lock(&fbc->lock); + spin_lock_irqsave(&fbc->lock, flags); pcount = per_cpu_ptr(fbc->counters, cpu); fbc->count += *pcount; *pcount = 0; - spin_unlock(&fbc->lock); + spin_unlock_irqrestore(&fbc->lock, flags); } mutex_unlock(&percpu_counters_lock); return NOTIFY_OK; |