On Fri, May 15, 2015 at 05:43:34PM +0200, Peter Zijlstra wrote:
> Because sched_setscheduler() checks p->flags & PF_NO_SETAFFINITY
> without locks, a caller might observe an old value and race with the
> set_cpus_allowed_ptr() call from __kthread_bind() and effectively undo
> it.
>
> __kthread_bind()
> do_set_cpus_allowed()
> <SYSCALL>
> sched_setaffinity()
> if (p->flags &
> PF_NO_SETAFFINITIY)
> set_cpus_allowed_ptr()
> p->flags |= PF_NO_SETAFFINITY
>
> Fix the issue by putting everything under the regular scheduler locks.
>
> This also closes a hole in the serialization of
> task_struct::{nr_,}cpus_allowed.
>
> Cc: Tejun Heo <[email protected]>
> Cc: Oleg Nesterov <[email protected]>
> Signed-off-by: Peter Zijlstra (Intel) <[email protected]>
For workqueue part,
Acked-by: Tejun Heo <[email protected]>
Please route anyway you see fit.
Thanks.
--
tejun
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