On Sun, 2023-06-18 at 12:40 +0200, Thorsten Leemhuis wrote: > On 16.06.23 22:54, Jeff Layton wrote: > > On Fri, 2023-06-16 at 16:27 -0400, Chuck Lever wrote: > > > Thanks Eirik and Jeff. > > > > > > At this point in the release cycle, I plan to apply this for the > > > next merge window (6.5). > > > > I think we should take this in sooner. This is a regression and a > > user-triggerable oops in the right situation. If: > > > > - non-x86_64 arch > > - /proc/fs/nfsd is mounted in the namespace > > - nfsd is not started in the namespace > > - unprivileged user calls "cat /proc/fs/nfsd/reply_cache_stats" > > FWIW, might be worth to simply tell Linus about it and let him decide, > that's totally fine and even documented in the old and the new docs for > handling regressions[1]. > > [1] > https://git.kernel.org/pub/scm/linux/kernel/git/next/linux-next.git/commit/Documentation/process/handling-regressions.rst?id=eed892da9cd08be76a8f467c600ef58716dbb4d2 > I'd rather Chuck make the final call here. The original patch description didn't point out how easy it is to trigger a panic with this, so I was hoping to convince him. To further that argument too: I have to wonder if this bug might cause (temporary?) memory corruption on x86_64. The code hits a spinlock in that struct, so there may be a window of time where it doesn't contain what's expected. > > > > Cc: stable@xxxxxxxxxxxxxxx # v6.3+ > > > > Fixes: f5f9d4a314da ("nfsd: move reply cache initialization into nfsd startup") > > > > > > Why both Fixes: and Cc: stable? > > > > *shrug* : they mean different things. I can drop the Cc stable. > > Please leave it, only a stable tag ensures backporting; a fixes tag > alone is not enough. See [1] above or these recent messages from Greg: > > https://lore.kernel.org/all/2023061137-algorithm-almanac-1337@gregkh/ > https://lore.kernel.org/all/2023060703-colony-shakily-3514@gregkh/ > Chuck and I also recently requested that the stable series not pick patches automatically for fs/nfsd. This does need to be backported though, so I cc'ed stable to make that clear. -- Jeff Layton <jlayton@xxxxxxxxxx>
