Return-Path: Received: (majordomo@vger.kernel.org) by vger.kernel.org via listexpand id S1754253AbcKYI6K (ORCPT ); Fri, 25 Nov 2016 03:58:10 -0500 Received: from mx2.suse.de ([195.135.220.15]:45346 "EHLO mx2.suse.de" rhost-flags-OK-OK-OK-OK) by vger.kernel.org with ESMTP id S1752895AbcKYIb3 (ORCPT ); Fri, 25 Nov 2016 03:31:29 -0500 X-Amavis-Alert: BAD HEADER SECTION, Duplicate header field: "References" From: Jiri Slaby To: stable@vger.kernel.org Cc: linux-kernel@vger.kernel.org, Andrey Ryabinin , Alexander Viro , Tejun Heo , "Rafael J. Wysocki" , Michal Hocko , Andrew Morton , Linus Torvalds , Jiri Slaby Subject: [PATCH 3.12 055/127] coredump: fix unfreezable coredumping task Date: Fri, 25 Nov 2016 09:29:28 +0100 Message-Id: <03ef87a54e5606bf5aab07fa4f47b19c3cff8501.1480062521.git.jslaby@suse.cz> X-Mailer: git-send-email 2.10.2 In-Reply-To: References: In-Reply-To: References: Sender: linux-kernel-owner@vger.kernel.org List-ID: X-Mailing-List: linux-kernel@vger.kernel.org Content-Length: 2102 Lines: 59 From: Andrey Ryabinin 3.12-stable review patch. If anyone has any objections, please let me know. =============== commit 70d78fe7c8b640b5acfad56ad341985b3810998a upstream. It could be not possible to freeze coredumping task when it waits for 'core_state->startup' completion, because threads are frozen in get_signal() before they got a chance to complete 'core_state->startup'. Inability to freeze a task during suspend will cause suspend to fail. Also CRIU uses cgroup freezer during dump operation. So with an unfreezable task the CRIU dump will fail because it waits for a transition from 'FREEZING' to 'FROZEN' state which will never happen. Use freezer_do_not_count() to tell freezer to ignore coredumping task while it waits for core_state->startup completion. Link: http://lkml.kernel.org/r/1475225434-3753-1-git-send-email-aryabinin@virtuozzo.com Signed-off-by: Andrey Ryabinin Acked-by: Pavel Machek Acked-by: Oleg Nesterov Cc: Alexander Viro Cc: Tejun Heo Cc: "Rafael J. Wysocki" Cc: Michal Hocko Signed-off-by: Andrew Morton Signed-off-by: Linus Torvalds Signed-off-by: Jiri Slaby --- fs/coredump.c | 3 +++ 1 file changed, 3 insertions(+) diff --git a/fs/coredump.c b/fs/coredump.c index 86753db01f2d..29950247a29a 100644 --- a/fs/coredump.c +++ b/fs/coredump.c @@ -1,6 +1,7 @@ #include #include #include +#include #include #include #include @@ -386,7 +387,9 @@ static int coredump_wait(int exit_code, struct core_state *core_state) if (core_waiters > 0) { struct core_thread *ptr; + freezer_do_not_count(); wait_for_completion(&core_state->startup); + freezer_count(); /* * Wait for all the threads to become inactive, so that * all the thread context (extended register state, like -- 2.10.2