From mboxrd@z Thu Jan 1 00:00:00 1970 Return-Path: Received: from mail.linuxfoundation.org ([140.211.169.12]:57570 "EHLO mail.linuxfoundation.org" rhost-flags-OK-OK-OK-OK) by vger.kernel.org with ESMTP id S932110AbcKOTIl (ORCPT ); Tue, 15 Nov 2016 14:08:41 -0500 Subject: Patch "coredump: fix unfreezable coredumping task" has been added to the 4.4-stable tree To: aryabinin@virtuozzo.com, akpm@linux-foundation.org, gregkh@linuxfoundation.org, mhocko@kernel.org, oleg@redhat.com, pavel@ucw.cz, rjw@rjwysocki.net, tj@kernel.org, torvalds@linux-foundation.org, viro@zeniv.linux.org.uk Cc: , From: Date: Tue, 15 Nov 2016 20:08:47 +0100 Message-ID: <1479236927136117@kroah.com> MIME-Version: 1.0 Content-Type: text/plain; charset=ANSI_X3.4-1968 Content-Transfer-Encoding: 8bit Sender: stable-owner@vger.kernel.org List-ID: This is a note to let you know that I've just added the patch titled coredump: fix unfreezable coredumping task to the 4.4-stable tree which can be found at: http://www.kernel.org/git/?p=linux/kernel/git/stable/stable-queue.git;a=summary The filename of the patch is: coredump-fix-unfreezable-coredumping-task.patch and it can be found in the queue-4.4 subdirectory. If you, or anyone else, feels it should not be added to the stable tree, please let know about it. >>From 70d78fe7c8b640b5acfad56ad341985b3810998a Mon Sep 17 00:00:00 2001 From: Andrey Ryabinin Date: Thu, 10 Nov 2016 10:46:38 -0800 Subject: coredump: fix unfreezable coredumping task 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: Greg Kroah-Hartman --- fs/coredump.c | 3 +++ 1 file changed, 3 insertions(+) --- a/fs/coredump.c +++ b/fs/coredump.c @@ -1,6 +1,7 @@ #include #include #include +#include #include #include #include @@ -399,7 +400,9 @@ static int coredump_wait(int exit_code, 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 Patches currently in stable-queue which might be from aryabinin@virtuozzo.com are queue-4.4/coredump-fix-unfreezable-coredumping-task.patch