From mboxrd@z Thu Jan 1 00:00:00 1970 Return-Path: From: Greg Kroah-Hartman To: linux-kernel@vger.kernel.org Cc: Greg Kroah-Hartman , stable@vger.kernel.org, "wang, biao" , Peter Zijlstra Subject: [ 21/44] klist: del waiter from klist_remove_waiters before wakeup waitting process Date: Wed, 5 Jun 2013 14:12:19 -0700 Message-Id: <20130605211224.082345886@linuxfoundation.org> In-Reply-To: <20130605211221.858177087@linuxfoundation.org> References: <20130605211221.858177087@linuxfoundation.org> Sender: linux-kernel-owner@vger.kernel.org List-ID: 3.4-stable review patch. If anyone has any objections, please let me know. ------------------ From: "wang, biao" commit ac5a2962b02f57dea76d314ef2521a2170b28ab6 upstream. 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(-) --- a/lib/klist.c +++ b/lib/klist.c @@ -193,10 +193,10 @@ static void klist_release(struct kref *k 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);