Re: [regression 6.1.y] discard/TRIM through RAID10 blocking (was: Re: Bug#1104460: linux-image-6.1.0-34-powerpc64le: Discard broken) with RAID10: BUG: kernel tried to execute user page (0) - exploit attempt?

[Salvatore Bonaccorso <carnil@debian.org>]

On Mon, May 05, 2025 at 04:00:31PM +0200, Salvatore Bonaccorso wrote:
> Hi Moritz,
> 
> On Mon, May 05, 2025 at 01:47:15PM +0200, Moritz Mühlenhoff wrote:
> > Am Wed, Apr 30, 2025 at 05:55:20PM +0200 schrieb Salvatore Bonaccorso:
> > > Hi
> > > 
> > > We got a regression report in Debian after the update from 6.1.133 to
> > > 6.1.135. Melvin is reporting that discard/trimm trhough a RAID10 array
> > > stalls idefintively. The full report is inlined below and originates
> > > from https://bugs.debian.org/1104460 .
> > 
> > JFTR, we ran into the same problem with a few Wikimedia servers running
> > 6.1.135 and RAID 10: The servers started to lock up once fstrim.service
> > got started. Full oops messages are available at
> > https://phabricator.wikimedia.org/P75746
> 
> Thanks for this aditional datapoints. Assuming you wont be able to
> thest the other stable series where the commit d05af90d6218
> ("md/raid10: fix missing discard IO accounting") went in, might you at
> least be able to test the 6.1.y branch with the commit reverted again
> and manually trigger the issue?
> 
> If needed I can provide a test Debian package of 6.1.135 (or 6.1.137)
> with the patch reverted. 

So one additional data point as several Debian users were reporting
back beeing affected: One user did upgrade to 6.12.25 (where the
commit was backported as well) and is not able to reproduce the issue
there.

This indicates we might miss some pre-requisites in the 6.1.y series?

user is trying now the 6.1.135 with patch reverted as well.

Regards,
Salvatore