Re: [PATCHSET v2 0/4] xfs: fix cpu hotplug mess

[Dave Chinner <david@fromorbit.com>]

On Tue, Aug 29, 2023 at 04:06:46PM -0700, Darrick J. Wong wrote:
> Hi all,
> 
> Ritesh and Eric separately reported crashes in XFS's hook function for
> CPU hot remove if the remove event races with a filesystem being
> mounted.  I also noticed via generic/650 that once in a while the log
> will shut down over an apparent overrun of a transaction reservation;
> this turned out to be due to CIL percpu list aggregation failing to pick
> up the percpu list items from a dying CPU.
> 
> Either way, the solution here is to eliminate the need for a CPU dying
> hook by using a private cpumask to track which CPUs have added to their
> percpu lists directly, and iterating with that mask.  This fixes the log
> problems and (I think) solves a theoretical UAF bug in the inodegc code
> too.
> 
> v2: fix a few put_cpu uses, add necessary memory barriers, and use
>     atomic cpumask operations
> 
> If you're going to start using this code, I strongly recommend pulling
> from my git trees, which are linked below.
> 
> This has been lightly tested with fstests.  Enjoy!
> Comments and questions are, as always, welcome.

Series looks good. Removes a bunch of code and makes things more
reliable, so what's not to like about it?

Reviewed-by: Dave Chinner <dchinner@redhat.com>

-- 
Dave Chinner
david@fromorbit.com