Commit ac5a2962 authored by wang, biao's avatar wang, biao Committed by Greg Kroah-Hartman

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: default avatarwang, biao <biao.wang@intel.com>
Acked-by: default avatarPeter Zijlstra <peterz@infradead.org>
Signed-off-by: default avatarGreg Kroah-Hartman <gregkh@linuxfoundation.org>
parent 97521978
...@@ -193,10 +193,10 @@ static void klist_release(struct kref *kref) ...@@ -193,10 +193,10 @@ static void klist_release(struct kref *kref)
if (waiter->node != n) if (waiter->node != n)
continue; continue;
list_del(&waiter->list);
waiter->woken = 1; waiter->woken = 1;
mb(); mb();
wake_up_process(waiter->process); wake_up_process(waiter->process);
list_del(&waiter->list);
} }
spin_unlock(&klist_remove_lock); spin_unlock(&klist_remove_lock);
knode_set_klist(n, NULL); knode_set_klist(n, NULL);
......
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