Messages in this thread Patch in this message | | | Date | Sun, 10 Feb 2013 13:22:43 +0800 | Subject | [PATCH 1/2] stop_machine: check work->done while handling enqueued works | From | Hillf Danton <> |
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In cpu_stopper_thread(), @work->done may be NULL if the cpu stop work is queued from stop_one_cpu_nowait(); however, cpu_stopper_thread() updates @done->ret without checking whether @done exists or not when the work function fails.
While this can lead to oops, the only current user of stop_one_cpu_nowait() - active_load_balance_cpu_stop() - always returns 0 and thus there's no in-kernel user which triggers this bug.
Fix it by checking whether @done exists before updating @done->ret.
Thanks Tejun for sharing commit message.
Signed-off-by: Hillf Danton <dhillf@gmail.com> Reviewed-by: Namhyung Kim <namhyung@kernel.org> ---
--- a/kernel/stop_machine.c Sun Feb 10 12:51:46 2013 +++ b/kernel/stop_machine.c Sun Feb 10 12:58:58 2013 @@ -279,7 +279,7 @@ repeat: preempt_disable();
ret = fn(arg); - if (ret) + if (ret && done) done->ret = ret;
/* restore preemption and check it's still balanced */ --
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