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Wed, 07 Jan 2026 09:45:50 -0800 (PST) From: Leo Martins To: Christian Heusel Cc: Gideon Farrell , linux-btrfs@vger.kernel.org, regressions@lists.linux.dev, arch-devops@lists.archlinux.org Subject: Re: refcount_warn_saturate in __btrfs_release_delayed_node for 6.18.2-arch2-1 Date: Wed, 7 Jan 2026 09:45:38 -0800 Message-ID: <20260107174547.3875297-1-loemra.dev@gmail.com> X-Mailer: git-send-email 2.47.3 In-Reply-To: <584c770b-8e59-457c-a8a4-0f9630ec9635@heusel.eu> References: Precedence: bulk X-Mailing-List: linux-btrfs@vger.kernel.org List-Id: List-Subscribe: List-Unsubscribe: MIME-Version: 1.0 Content-Transfer-Encoding: 8bit On Wed, 7 Jan 2026 14:15:56 +0100 Christian Heusel wrote: > On 26/01/07 02:52AM, Christian Heusel wrote: > > On 26/01/06 05:10PM, Leo Martins wrote: > > > On Tue, 06 Jan 2026 22:01:58 +0000 "Gideon Farrell" wrote: > > > > > > > Hi there, > > > > > > > > I recently experienced a type of crash I haven't seen before on this system which seems to originate in __btrfs_release_delayed_node on Kernel 6.18.2-arch2-1. > > > > > > Hey, thanks for the report. This looks very similar to a different > > > report that has been fixed in 6.19-rc5. > > > Report: https://lore.kernel.org/oe-lkp/202511262228.6dda231e-lkp@intel.com/ > > > > I think this is the issue we have been seeing on the Arch Linux > > infrastructure aswell, see this issue for reference: > > > > https://gitlab.archlinux.org/archlinux/infrastructure/-/issues/788#note_385420 > > > > This has caused us to downgrade the kernel on all hosts in our > > infrastructure due to the crashes caused by this. > > > > > Fix: https://lore.kernel.org/linux-btrfs/7c89417ac3352ce3cb0a6373a1746155c1e2754d.1765588168.git.loemra.dev@gmail.com/ > > > > > > Please let me know if this fixes your issue. > > > > So far we have not found a good lab-setting to reproduce the issue > > outside of the production machines workloads (but we have also not > > looked into the issue a lot). > > > > Do you have a good reproducer already that we could use to verify the > > fix? I believe the lkp-test from the original report is able to consistently reproduce this. > > > > Also the fix is not yet even scheduled for inclusion in the stable > > trees, since it is still not in linus tree right? > > Sorry, I messed up here! I got fooled by the output of `git log --grep` > and therefore missed the commit! As pointed out by heftig on gitlab the > commit already is present in 6.18.3 which I'll try to roll out to our > systems shortly! :) Let me know if you're still seeing any issues after rolling out the fix. Thanks, Leo Martins. > > > > > > > > > > > > > > Here's the stack trace: > > > > > > > > ``` > > > > > > Are these the first refcount_t: warnings in your dmesg? I would > > > expect an earlier warning that looks like > > > refcount_t: addition on 0; use-after-free. > > > > > > > This is what our stacktrace looks like: > > > > [...] > > > > Cheers, > > Chris > > >