From ac5a2962b02f57dea76d314ef2521a2170b28ab6 Mon Sep 17 00:00:00 2001 From: "wang, biao" Date: Thu, 16 May 2013 09:50:13 +0800 Subject: [PATCH] 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 Acked-by: Peter Zijlstra Signed-off-by: Greg Kroah-Hartman --- lib/klist.c | 2 +- 1 file changed, 1 insertion(+), 1 deletion(-) 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); -- 2.20.1