From mboxrd@z Thu Jan 1 00:00:00 1970 Return-Path: Received: (majordomo@vger.kernel.org) by vger.kernel.org via listexpand id S1752858AbbCXUzP (ORCPT ); Tue, 24 Mar 2015 16:55:15 -0400 Received: from mailapp01.imgtec.com ([195.59.15.196]:37380 "EHLO mailapp01.imgtec.com" rhost-flags-OK-OK-OK-OK) by vger.kernel.org with ESMTP id S1752212AbbCXUzL (ORCPT ); Tue, 24 Mar 2015 16:55:11 -0400 From: Alistair Strachan To: CC: Alistair Strachan , Maarten Lankhorst , Greg Kroah-Hartman , Colin Cross Subject: [PATCH] sync: Fix memory corruption in sync_timeline_signal(). Date: Tue, 24 Mar 2015 13:55:04 -0700 Message-ID: <1427230504-8279-1-git-send-email-alistair.strachan@imgtec.com> X-Mailer: git-send-email 2.1.4 X-OriginalArrivalTime: 24 Mar 2015 20:55:09.0539 (UTC) FILETIME=[D094B330:01D06674] MIME-Version: 1.0 Content-Type: text/plain Sender: linux-kernel-owner@vger.kernel.org List-ID: X-Mailing-List: linux-kernel@vger.kernel.org The android_fence_release() function checks for active sync points by calling list_empty() on the list head embedded on the sync point. However, it is only valid to use list_empty() on nodes that have been initialized with INIT_LIST_HEAD() or list_del_init(). Because the list entry has likely been removed from the active list by sync_timeline_signal(), there is a good chance that this WARN_ON_ONCE() will be hit due to dangling pointers pointing at freed memory (even though the sync drivers did nothing wrong) and memory corruption will ensue as the list entry is removed for a second time, corrupting the active list. This problem can be reproduced quite easily with CONFIG_DEBUG_LIST=y and fences with more than one sync point. Change-Id: Ie2a6bc1480bbcfdc14f9b385fca5a2b833effc05 Signed-off-by: Alistair Strachan Cc: Maarten Lankhorst Cc: Greg Kroah-Hartman Cc: Colin Cross --- drivers/staging/android/sync.c | 2 +- 1 file changed, 1 insertion(+), 1 deletion(-) diff --git a/drivers/staging/android/sync.c b/drivers/staging/android/sync.c index 7bdb62b..f83e00c 100644 --- a/drivers/staging/android/sync.c +++ b/drivers/staging/android/sync.c @@ -114,7 +114,7 @@ void sync_timeline_signal(struct sync_timeline *obj) list_for_each_entry_safe(pt, next, &obj->active_list_head, active_list) { if (fence_is_signaled_locked(&pt->base)) - list_del(&pt->active_list); + list_del_init(&pt->active_list); } spin_unlock_irqrestore(&obj->child_list_lock, flags); -- 2.1.4