Re: [Patch] perf_event: fix a race condition in perf_remove_from_context()

2014-09-02 Thread Cong Wang
On Mon, Sep 1, 2014 at 1:38 AM, Peter Zijlstra wrote: > On Thu, Aug 28, 2014 at 04:27:35PM -0700, Cong Wang wrote: >> From: Cong Wang >> >> We saw a kernel soft lockup in perf_remove_from_context(), >> it looks like the `perf` process, when exiting, could not go >> out of the retry loop. Meanwhil

Re: [Patch] perf_event: fix a race condition in perf_remove_from_context()

2014-09-01 Thread Peter Zijlstra
On Thu, Aug 28, 2014 at 04:27:35PM -0700, Cong Wang wrote: > From: Cong Wang > > We saw a kernel soft lockup in perf_remove_from_context(), > it looks like the `perf` process, when exiting, could not go > out of the retry loop. Meanwhile, the target process was forking > a child. So either the ta

[Patch] perf_event: fix a race condition in perf_remove_from_context()

2014-08-28 Thread Cong Wang
From: Cong Wang We saw a kernel soft lockup in perf_remove_from_context(), it looks like the `perf` process, when exiting, could not go out of the retry loop. Meanwhile, the target process was forking a child. So either the target process should execute the smp function call to deactive the event