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 <stable@xxxxxxxxxxxxxxx> know about it.
>From 70d78fe7c8b640b5acfad56ad341985b3810998a Mon Sep 17 00:00:00 2001
From: Andrey Ryabinin <aryabinin@xxxxxxxxxxxxx>
Date: Thu, 10 Nov 2016 10:46:38 -0800
Subject: coredump: fix unfreezable coredumping task
From: Andrey Ryabinin <aryabinin@xxxxxxxxxxxxx>
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@xxxxxxxxxxxxx
Signed-off-by: Andrey Ryabinin <aryabinin@xxxxxxxxxxxxx>
Acked-by: Pavel Machek <pavel@xxxxxx>
Acked-by: Oleg Nesterov <oleg@xxxxxxxxxx>
Cc: Alexander Viro <viro@xxxxxxxxxxxxxxxxxx>
Cc: Tejun Heo <tj@xxxxxxxxxx>
Cc: "Rafael J. Wysocki" <rjw@xxxxxxxxxxxxx>
Cc: Michal Hocko <mhocko@xxxxxxxxxx>
Signed-off-by: Andrew Morton <akpm@xxxxxxxxxxxxxxxxxxxx>
Signed-off-by: Linus Torvalds <torvalds@xxxxxxxxxxxxxxxxxxxx>
Signed-off-by: Greg Kroah-Hartman <gregkh@xxxxxxxxxxxxxxxxxxx>
---
fs/coredump.c | 3 +++
1 file changed, 3 insertions(+)
--- a/fs/coredump.c
+++ b/fs/coredump.c
@@ -1,6 +1,7 @@
#include <linux/slab.h>
#include <linux/file.h>
#include <linux/fdtable.h>
+#include <linux/freezer.h>
#include <linux/mm.h>
#include <linux/stat.h>
#include <linux/fcntl.h>
@@ -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@xxxxxxxxxxxxx are
queue-4.4/coredump-fix-unfreezable-coredumping-task.patch
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