Messages in this thread | | | Date | Wed, 22 Jun 2022 16:09:44 +0100 | From | Mel Gorman <> | Subject | Re: Lockups due to "locking/rwsem: Make handoff bit handling more consistent" |
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On Tue, Jun 21, 2022 at 09:32:12PM -0400, Waiman Long wrote: > On 6/20/22 10:09, Mel Gorman wrote: > > On Fri, Jun 17, 2022 at 10:29:20AM -0400, Waiman Long wrote: > > > > The C file and shell script to run it are attached. > > > > > > > Thanks for the reproducer and I will try to reproduce it locally. > > > > > > It is a known issue that I have receive similar report from an Oracle > > > engineer. That is the reason I posted commit 1ee326196c66 ("locking/rwsem: > > > Always try to wake waiters in out_nolock path") that was merged in v5.19. I > > > believe it helps but it may not be able to eliminate all possible race > > > conditions. To make rwsem behave more like before commit d257cc8cb8d5 > > > ("locking/rwsem: Make handoff bit handling more consistent"), I posted a > > > follow-up patch > > > > > > https://lore.kernel.org/lkml/20220427173124.1428050-1-longman@redhat.com/ > > > > > > But it hasn't gotten review yet. > > > > > FWIW, the patch passed the test case when applied to both 5.18 and > > 5.19-rc3. > > Thanks for running the test. Do you mean that both 5.18 and 5.19-rc3 fail > the test and they pass only after applying the patch? >
Yes.
> Anyway, I am not able to reproduce the failure in both 5.18 and 5.19-rc3. > Perhaps it is due to the difference in the running environment, i.e. gcc, > glibc, etc. What operating environment (SuSE version) do you use to > reproduce the failure? I used RHEL8 which is the most convenient one for me. >
It was reproduced on Leap 15.4 with a 2-socket machine with 40 cores (SMT-2). The kernel built was based on the distribution config. gcc version was based on 7.5.0.
> BTW, do you mind if I put down your name with a "Tested-by:" tag to the > patch? >
No problem.
-- Mel Gorman SUSE Labs
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