Messages in this thread | | | Date | Thu, 22 Aug 2019 15:21:07 -0700 | From | Andrew Morton <> | Subject | Re: [PATCH v3] psi: get poll_work to run when calling poll syscall next time |
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On Wed, 21 Aug 2019 11:26:25 +0800 Joseph Qi <joseph.qi@linux.alibaba.com> wrote:
> Only when calling the poll syscall the first time can user > receive POLLPRI correctly. After that, user always fails to > acquire the event signal. > > Reproduce case: > 1. Get the monitor code in Documentation/accounting/psi.txt > 2. Run it, and wait for the event triggered. > 3. Kill and restart the process. > > The question is why we can end up with poll_scheduled = 1 but the work > not running (which would reset it to 0). And the answer is because the > scheduling side sees group->poll_kworker under RCU protection and then > schedules it, but here we cancel the work and destroy the worker. The > cancel needs to pair with resetting the poll_scheduled flag.
Should this be backported into -stable kernels?
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