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| author |   Kirill Tkhai <ktkhai@parallels.com> | 2014-10-27 14:18:25 +0400 |
|---|---|---|
| committer |   Ingo Molnar <mingo@kernel.org> | 2014-10-28 10:45:59 +0100 |
| commit | eeb61e53ea19be0c4015b00b2e8b3b2185436f2b (patch) | |
| tree | 87ed33506d580130ac59cc231a6e112c4042b96d /kernel | |
| parent | Linux 3.18-rc2 (diff) | |
| download | linux-dev-eeb61e53ea19be0c4015b00b2e8b3b2185436f2b.tar.xz linux-dev-eeb61e53ea19be0c4015b00b2e8b3b2185436f2b.zip | |
sched: Fix race between task_group and sched_task_group
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>
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 44999505e1bf..dde8adb7d0c0 100644 --- a/kernel/sched/core.c +++ b/kernel/sched/core.c @@ -7833,6 +7833,11 @@ 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) { @@ -8205,6 +8210,7 @@ struct cgroup_subsys cpu_cgrp_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, |