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authorEric Dumazet <dada1@cosmosbay.com>2008-12-09 13:14:11 -0800
committerLinus Torvalds <torvalds@linux-foundation.org>2008-12-10 08:01:52 -0800
commitfd3d664fef97cf01f8e28fe0b024ad52f3bbc1bc (patch)
treecc1b4d38e5ebd88c25b2bcee684c9e882be9a2ac /lib/percpu_counter.c
parentfe102c71a65a503646bcc94ccb6859da613c2f4f (diff)
downloadlinux-linaro-precise-fd3d664fef97cf01f8e28fe0b024ad52f3bbc1bc.tar.gz
percpu_counter: fix CPU unplug race in percpu_counter_destroy()
We should first delete the counter from percpu_counters list before freeing memory, or a percpu_counter_hotcpu_callback() could dereference a NULL pointer. Signed-off-by: Eric Dumazet <dada1@cosmosbay.com> Acked-by: David S. Miller <davem@davemloft.net> Cc: Peter Zijlstra <a.p.zijlstra@chello.nl> Cc: Mingming Cao <cmm@us.ibm.com> Signed-off-by: Andrew Morton <akpm@linux-foundation.org> Signed-off-by: Linus Torvalds <torvalds@linux-foundation.org>
Diffstat (limited to 'lib/percpu_counter.c')
-rw-r--r--lib/percpu_counter.c4
1 files changed, 2 insertions, 2 deletions
diff --git a/lib/percpu_counter.c b/lib/percpu_counter.c
index a8663890a88..71b265c330c 100644
--- a/lib/percpu_counter.c
+++ b/lib/percpu_counter.c
@@ -104,13 +104,13 @@ void percpu_counter_destroy(struct percpu_counter *fbc)
if (!fbc->counters)
return;
- free_percpu(fbc->counters);
- fbc->counters = NULL;
#ifdef CONFIG_HOTPLUG_CPU
mutex_lock(&percpu_counters_lock);
list_del(&fbc->list);
mutex_unlock(&percpu_counters_lock);
#endif
+ free_percpu(fbc->counters);
+ fbc->counters = NULL;
}
EXPORT_SYMBOL(percpu_counter_destroy);