From mboxrd@z Thu Jan 1 00:00:00 1970 Received: (majordomo@vger.kernel.org) by vger.kernel.org via listexpand id S1754543AbdBETrj (ORCPT + 2 others); Sun, 5 Feb 2017 14:47:39 -0500 Received: from wtarreau.pck.nerim.net ([62.212.114.60]:28244 "EHLO 1wt.eu" rhost-flags-OK-OK-OK-OK) by vger.kernel.org with ESMTP id S1753764AbdBET0a (ORCPT ); Sun, 5 Feb 2017 14:26:30 -0500 From: Willy Tarreau To: linux-kernel@vger.kernel.org, stable@vger.kernel.org, linux@roeck-us.net Cc: Andrey Ryabinin , Alexander Viro , Tejun Heo , "Rafael J. Wysocki" , Michal Hocko , Andrew Morton , Linus Torvalds , Willy Tarreau Subject: [PATCH 3.10 105/319] coredump: fix unfreezable coredumping task Date: Sun, 5 Feb 2017 20:18:47 +0100 Message-Id: <1486322541-8206-6-git-send-email-w@1wt.eu> X-Mailer: git-send-email 2.8.0.rc2.1.gbe9624a In-Reply-To: <1486322541-8206-1-git-send-email-w@1wt.eu> References: <1486322541-8206-1-git-send-email-w@1wt.eu> Sender: linux-kernel-owner@vger.kernel.org List-ID: X-Mailing-List: linux-kernel@vger.kernel.org Return-Path: From: Andrey Ryabinin 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: Willy Tarreau --- fs/coredump.c | 3 +++ 1 file changed, 3 insertions(+) diff --git a/fs/coredump.c b/fs/coredump.c index 4f03b2b..a94f94d 100644 --- a/fs/coredump.c +++ b/fs/coredump.c @@ -1,6 +1,7 @@ #include #include #include +#include #include #include #include @@ -375,7 +376,9 @@ 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 -- 2.8.0.rc2.1.gbe9624a