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| author | Kirill Tkhai <ktkhai@parallels.com> | 2014-10-27 14:18:25 +0400 |
|---|---|---|
| committer | Jiri Slaby <jslaby@suse.cz> | 2016-04-11 16:43:49 +0200 |
| commit | 5f3284939089d34d1a7685ad83aeca797c3896ae (patch) | |
| tree | e5dc33cab45daba426baf75b35c5a743c44766d0 /kernel | |
| parent | d1f8a33ffa14fa975e3ee41a89e53b302e305c30 (diff) | |
| download | linux-stable-5f3284939089d34d1a7685ad83aeca797c3896ae.tar.gz linux-stable-5f3284939089d34d1a7685ad83aeca797c3896ae.tar.bz2 linux-stable-5f3284939089d34d1a7685ad83aeca797c3896ae.zip | |
sched: Fix race between task_group and sched_task_group
commit eeb61e53ea19be0c4015b00b2e8b3b2185436f2b upstream.
The race may happen when somebody is changing task_group of a forking task.
Child's cgroup is the same as parent's after dup_task_struct() (there just
memory copying). Also, cfs_rq and rt_rq are the same as parent's.
But if parent changes its task_group before it's called cgroup_post_fork(),
we do not reflect this situation on child. Child's cfs_rq and rt_rq remain
the same, while child's task_group changes in cgroup_post_fork().
To fix this we introduce fork() method, which calls sched_move_task() directly.
This function changes sched_task_group on appropriate (also its logic has
no problem with freshly created tasks, so we shouldn't introduce something
special; we are able just to use it).
Possibly, this decides the Burke Libbey's problem: https://lkml.org/lkml/2014/10/24/456
Signed-off-by: Kirill Tkhai <ktkhai@parallels.com>
Signed-off-by: Peter Zijlstra (Intel) <peterz@infradead.org>
Cc: Linus Torvalds <torvalds@linux-foundation.org>
Link: http://lkml.kernel.org/r/1414405105.19914.169.camel@tkhai
Signed-off-by: Ingo Molnar <mingo@kernel.org>
Signed-off-by: Jiri Slaby <jslaby@suse.cz>
Diffstat (limited to 'kernel')
| -rw-r--r-- | kernel/sched/core.c | 6 |
1 files changed, 6 insertions, 0 deletions
diff --git a/kernel/sched/core.c b/kernel/sched/core.c index 3800316d7424..7381119ec1e9 100644 --- a/kernel/sched/core.c +++ b/kernel/sched/core.c @@ -7233,6 +7233,11 @@ static void cpu_cgroup_css_offline(struct cgroup_subsys_state *css) sched_offline_group(tg); } +static void cpu_cgroup_fork(struct task_struct *task) +{ + sched_move_task(task); +} + static int cpu_cgroup_can_attach(struct cgroup_subsys_state *css, struct cgroup_taskset *tset) { @@ -7602,6 +7607,7 @@ struct cgroup_subsys cpu_cgroup_subsys = { .css_free = cpu_cgroup_css_free, .css_online = cpu_cgroup_css_online, .css_offline = cpu_cgroup_css_offline, + .fork = cpu_cgroup_fork, .can_attach = cpu_cgroup_can_attach, .attach = cpu_cgroup_attach, .exit = cpu_cgroup_exit, |