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| author | Peter Zijlstra <peterz@infradead.org> | 2010-06-22 11:44:53 +0200 |
|---|---|---|
| committer | Paul E. McKenney <paulmck@linux.vnet.ibm.com> | 2010-06-23 15:14:09 -0700 |
| commit | 8695159967957015f8dfb49315d6f88e111d90e0 (patch) | |
| tree | d575083d37a069be585d575ec036faa8765f1d0c /kernel | |
| parent | 94bfa3b6692c7a3f6f119596724204ec975d3ef0 (diff) | |
| download | linux-8695159967957015f8dfb49315d6f88e111d90e0.tar.gz linux-8695159967957015f8dfb49315d6f88e111d90e0.tar.bz2 linux-8695159967957015f8dfb49315d6f88e111d90e0.zip | |
sched: silence PROVE_RCU in sched_fork()
Because cgroup_fork() is ran before sched_fork() [ from copy_process() ]
and the child's pid is not yet visible the child is pinned to its
cgroup. Therefore we can silence this warning.
A nicer solution would be moving cgroup_fork() to right after
dup_task_struct() and exclude PF_STARTING from task_subsys_state().
Signed-off-by: Peter Zijlstra <a.p.zijlstra@chello.nl>
Reviewed-by: Li Zefan <lizf@cn.fujitsu.com>
Signed-off-by: Paul E. McKenney <paulmck@linux.vnet.ibm.com>
Diffstat (limited to 'kernel')
| -rw-r--r-- | kernel/sched.c | 9 |
1 files changed, 9 insertions, 0 deletions
diff --git a/kernel/sched.c b/kernel/sched.c index f8b8996228dd..a2d215d132f6 100644 --- a/kernel/sched.c +++ b/kernel/sched.c @@ -2494,7 +2494,16 @@ void sched_fork(struct task_struct *p, int clone_flags) if (p->sched_class->task_fork) p->sched_class->task_fork(p); + /* + * The child is not yet in the pid-hash so no cgroup attach races, + * and the cgroup is pinned to this child due to cgroup_fork() + * is ran before sched_fork(). + * + * Silence PROVE_RCU. + */ + rcu_read_lock(); set_task_cpu(p, cpu); + rcu_read_unlock(); #if defined(CONFIG_SCHEDSTATS) || defined(CONFIG_TASK_DELAY_ACCT) if (likely(sched_info_on())) |