linux-kernel - Re: [GIT PULL] gfs2 fixes

lists.openwall.net		lists / announce owl-users owl-dev john-users john-dev passwdqc-users yescrypt popa3d-users / oss-security kernel-hardening musl sabotage tlsify passwords / crypt-dev xvendor / Bugtraq Full-Disclosure linux-kernel linux-netdev linux-ext4 linux-hardening linux-cve-announce PHC
Open Source and information security mailing list archives

Hash Suite: Windows password security audit tool. GUI, reports in PDF.

[<prev] [next>] [<thread-prev] [day] [month] [year] [list]

Message-ID: <CAHc6FU7rMvu=Wry=VOXRv1191xooo+r8Cnv4XwYQysAr1hRFYw@mail.gmail.com>
Date:   Fri, 11 Feb 2022 22:40:41 +0100
From:   Andreas Gruenbacher <agruenba@...hat.com>
To:     Linus Torvalds <torvalds@...ux-foundation.org>
Cc:     cluster-devel <cluster-devel@...hat.com>,
        Linux Kernel Mailing List <linux-kernel@...r.kernel.org>
Subject: Re: [GIT PULL] gfs2 fixes

On Fri, Feb 11, 2022 at 8:48 PM Linus Torvalds
<torvalds@...ux-foundation.org> wrote:
> On Fri, Feb 11, 2022 at 9:05 AM Andreas Gruenbacher <agruenba@...hat.com> wrote:
> >
> > * Revert debug commit that causes unexpected data corruption.
>
> Well, apparently not just unexpected, but unexplained too.
>
> That's a bit worrisome. It sounds like the corruption cause is still
> there, just hidden by the lack of __cond_resched()?

Yes, that's what it looks like. My initial suspicion was that we're
somewhere using gfs2_glock_dq() in non-sleepable context when we know
that we're not dropping the last reference and so gfs2_glock_dq()
won't sleep, but there's no such instance in the code, and testing
would also have revealed such cases. The corruption we've seen always
affects whole pages/blocks. Maybe it's an ordering / memory barrier
issue.

Thanks,
Andreas