On Thu, Dec 12, 2024 at 10:02 AM Johannes Thumshirn Johannes.Thumshirn@wdc.com wrote:
On 12.12.24 09:53, Daniel Vacek wrote:
On Thu, Dec 12, 2024 at 9:35 AM Johannes Thumshirn Johannes.Thumshirn@wdc.com wrote:
On 12.12.24 09:09, Daniel Vacek wrote:
Hi Johannes,
On Thu, Dec 12, 2024 at 9:00 AM Johannes Thumshirn Johannes.Thumshirn@wdc.com wrote:
On 12.12.24 08:54, Daniel Vacek wrote:
While testing the encoded read feature the following crash was observed and it can be reliably reproduced:
Hi Daniel,
This suspiciously looks like '05b36b04d74a ("btrfs: fix use-after-free in btrfs_encoded_read_endio()")'. Do you have this patch applied to your kernel? IIRC it went upstream with 6.13-rc2.
Yes, I do. This one is on top of it. The crash happens with `05b36b04d74a` applied. All the crashes were reproduced with `feffde684ac2`.
Honestly, `05b36b04d74a` looks a bit suspicious to me as it really does not look to deal correctly with the issue to me. I was a bit surprised/puzzled.
Can you elaborate why?
As it only touches one of those four atomic_dec_... lines. In theory the issue can happen also on the two async places, IIUC. It's only a matter of race probability.
Anyways, I could reproduce the crash in a matter of half an hour. With this fix the torture is surviving for 22 hours atm.
Do you also have '3ff867828e93 ("btrfs: simplify waiting for encoded read endios")'? Looking at the diff it doesn't seems so.
I cannot find that one. Am I missing something? Which repo are you using?
The for-next branch for btrfs [1], which is what ppl developing against btrfs should use. Can you please re-test with it and if needed re-base your patch on top of it?
[1] https://github.com/btrfs/linux for-next
I did check here and I don't really see the commit.
$ git remote -v origin https://github.com/btrfs/linux.git (fetch) origin https://github.com/btrfs/linux.git (push) $ git fetch $ git show 3ff867828e93 -- fatal: bad revision '3ff867828e93'
Note, I was testing v6.13-rc1. This is a fix not a feature development.
--nX
Thanks, Johannes