Messages in this thread | | | Date | Fri, 28 Jun 2019 22:46:08 +0200 | From | Peter Zijlstra <> | Subject | Re: [PATCH] perf: Fix race between close() and fork() |
| |
On Fri, Jun 28, 2019 at 05:50:03PM +0100, Mark Rutland wrote: > > + /* > > + * Wake any perf_event_free_task() waiting for this event to be > > + * freed. > > + */ > > + smp_mb(); /* pairs with wait_var_event() */ > > + wake_up_var(var); > > Huh, so wake_up_var() doesn't imply a RELEASE? > > As an aside, doesn't that mean all callers of wake_up_var() have to do > likewise to ensure it isn't re-ordered with whatever prior stuff they're > trying to notify waiters about? Several do an smp_store_release() then a > wake_up_var(), but IIUC the wake_up_var() could get pulled before that > release...
Yah,...
https://lkml.kernel.org/r/20190624165012.GH3436@hirez.programming.kicks-ass.net
I needs to get back to that.
| |