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authorwang, biao <biao.wang@intel.com>2013-05-16 09:50:13 +0800
committerGreg Kroah-Hartman <gregkh@linuxfoundation.org>2013-05-21 10:16:39 -0700
commitac5a2962b02f57dea76d314ef2521a2170b28ab6 (patch)
tree07c5b125c8b80182fedd9fd74098b79647f7a08f /lib
parent97521978c5ea80857d4f4f74d4e1fc93721482cf (diff)
downloadlwn-ac5a2962b02f57dea76d314ef2521a2170b28ab6.tar.gz
lwn-ac5a2962b02f57dea76d314ef2521a2170b28ab6.zip
klist: del waiter from klist_remove_waiters before wakeup waitting process
There is a race between klist_remove and klist_release. klist_remove uses a local var waiter saved on stack. When klist_release calls wake_up_process(waiter->process) to wake up the waiter, waiter might run immediately and reuse the stack. Then, klist_release calls list_del(&waiter->list) to change previous wait data and cause prior waiter thread corrupt. The patch fixes it against kernel 3.9. Signed-off-by: wang, biao <biao.wang@intel.com> Acked-by: Peter Zijlstra <peterz@infradead.org> Signed-off-by: Greg Kroah-Hartman <gregkh@linuxfoundation.org>
Diffstat (limited to 'lib')
-rw-r--r--lib/klist.c2
1 files changed, 1 insertions, 1 deletions
diff --git a/lib/klist.c b/lib/klist.c
index 0874e41609a6..358a368a2947 100644
--- a/lib/klist.c
+++ b/lib/klist.c
@@ -193,10 +193,10 @@ static void klist_release(struct kref *kref)
if (waiter->node != n)
continue;
+ list_del(&waiter->list);
waiter->woken = 1;
mb();
wake_up_process(waiter->process);
- list_del(&waiter->list);
}
spin_unlock(&klist_remove_lock);
knode_set_klist(n, NULL);