This is a note to let you know that I've just added the patch titled
sched/autogroup: Fix race with task_groups list
to the 3.10-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:
sched-autogroup-fix-race-with-task_groups-list.patch
and it can be found in the queue-3.10 subdirectory.
If you, or anyone else, feels it should not be added to the stable tree,
please let <stable@xxxxxxxxxxxxxxx> know about it.
>From 41261b6a832ea0e788627f6a8707854423f9ff49 Mon Sep 17 00:00:00 2001
From: Gerald Schaefer <gerald.schaefer@xxxxxxxxxx>
Date: Fri, 24 May 2013 18:07:49 +0200
Subject: sched/autogroup: Fix race with task_groups list
From: Gerald Schaefer <gerald.schaefer@xxxxxxxxxx>
commit 41261b6a832ea0e788627f6a8707854423f9ff49 upstream.
In autogroup_create(), a tg is allocated and added to the task_groups
list. If CONFIG_RT_GROUP_SCHED is set, this tg is then modified while on
the list, without locking. This can race with someone walking the list,
like __enable_runtime() during CPU unplug, and result in a use-after-free
bug.
To fix this, move sched_online_group(), which adds the tg to the list,
to the end of the autogroup_create() function after the modification.
Signed-off-by: Gerald Schaefer <gerald.schaefer@xxxxxxxxxx>
Signed-off-by: Peter Zijlstra <peterz@xxxxxxxxxxxxx>
Link: http://lkml.kernel.org/r/1369411669-46971-2-git-send-email-gerald.schaefer@xxxxxxxxxx
Signed-off-by: Ingo Molnar <mingo@xxxxxxxxxx>
Signed-off-by: Preeti U Murthy <preeti@xxxxxxxxxxxxxxxxxx>
Signed-off-by: Greg Kroah-Hartman <gregkh@xxxxxxxxxxxxxxxxxxx>
---
kernel/sched/auto_group.c | 3 +--
1 file changed, 1 insertion(+), 2 deletions(-)
--- a/kernel/sched/auto_group.c
+++ b/kernel/sched/auto_group.c
@@ -77,8 +77,6 @@ static inline struct autogroup *autogrou
if (IS_ERR(tg))
goto out_free;
- sched_online_group(tg, &root_task_group);
-
kref_init(&ag->kref);
init_rwsem(&ag->lock);
ag->id = atomic_inc_return(&autogroup_seq_nr);
@@ -98,6 +96,7 @@ static inline struct autogroup *autogrou
#endif
tg->autogroup = ag;
+ sched_online_group(tg, &root_task_group);
return ag;
out_free:
Patches currently in stable-queue which might be from gerald.schaefer@xxxxxxxxxx are
queue-3.10/sched-autogroup-fix-race-with-task_groups-list.patch
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