On Tue, May 5, 2020 at 1:04 PM Andrew Morton akpm@linux-foundation.org wrote:
On Tue, 05 May 2020 10:42:05 +0200 Roman Penyaev rpenyaev@suse.de wrote:
May I ask you to remove "epoll: ensure ep_poll() doesn't miss wakeup events" from your -mm queue? Jason lately found out that the patch does not fully solve the problem and this one patch is a second attempt to do things correctly in a different way (namely to do the final check under the lock). Previous changes are not needed.
Where do we stand with Khazhismel's "eventpoll: fix missing wakeup for ovflist in ep_poll_callback"?
http://lkml.kernel.org/r/20200424190039.192373-1-khazhy@google.com
My understanding is - we need the ep_poll_callback fix on a logical level (ovfllist was never triggering wakeup), and the two follow-ups close races - in both how we add/remove from the wait queue, and how we observe the ready list, which are needed if we only wake when we add events, where before we were also waking when we were splicing ovflist events when reading the ready list. As well, the first two together are needed for epoll60 to pass in my testing.
Khazhy