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SubjectRe: [PATCH 2/2] stop_machine: dequeue work before signal completion
On Sun, Feb 10, 2013 at 01:26:11PM +0800, Hillf Danton wrote:
> When a CPU is finally put down in either CPU_UP_CANCELLED or
> CPU_POST_DEAD, cpu_stop_cpu_callback() signals immediate completion on
> all cpu_stop_works still queued on the dead CPU; unfortunately, this
> code is buggy in that it doesn't remove the canceled work items off
> the stopper->works leaving it corrupted, which will trigger BUG_ON()
> during CPU_UP_PREPARE if the CPU is brought back online.
>
> This bug isn't easily triggered because CPU_DOWN has to race against
> cpu_stop calls and most, if not all, cpu stop users pin target CPUs.
>
> Fix it by popping each work item off stopper->works.
>
> Thanks Tejun for sharing commit message, again.
>
> Signed-off-by: Hillf Danton <dhillf@gmail.com>
> Reviewed-by: Namhyung Kim <namhyung@kernel.org>
> Cc: stable@vger.kernel.org

Acked-by: Tejun Heo <tj@kernel.org>

Andrew, this one too.

Thank you!

--
tejun


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