Commit ac5a2962 authored May 16, 2013 by wang, biao Committed by Greg Kroah-Hartman May 21, 2013

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>

parent 97521978

lib/klist.c

+1 −1

Original line number	Diff line number	Diff line
		@@ -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);