On Tue, Oct 22, 2024 at 01:44:08PM +0800, Lai, Yi wrote: > On Mon, Oct 21, 2024 at 05:20:12PM +0200, Niklas Cassel wrote: > > On Mon, Oct 21, 2024 at 02:07:21PM +0200, Niklas Cassel wrote: > > > Hello Yi Lai, > > > > > > On Mon, Oct 21, 2024 at 06:58:59PM +0800, Lai, Yi wrote: > > > > Hi Niklas Cassel, > > > > > > > > Greetings! > > > > > > > > I used Syzkaller and found that there is INFO: task hung in blk_mq_get_tag in v6.12-rc3 > > > > > > > > After bisection and the first bad commit is: > > > > " > > > > e5dd410acb34 ata: libata: Clear DID_TIME_OUT for ATA PT commands with sense data > > > > " > > > > > > It might be that your bisection results are accurate. > > > > > > However, after looking at the stacktraces, I find it way more likely that > > > bisection has landed on the wrong commit. > > > > > > See this series that was just queued (for 6.13) a few days ago that solves a > > > similar starvation: > > > https://lore.kernel.org/linux-block/20241014092934.53630-1-songmuchun@xxxxxxxxxxxxx/ > > > https://git.kernel.org/pub/scm/linux/kernel/git/axboe/linux-block.git/log/?h=for-6.13/block > > > > > > You could perhaps run with v6.14-rc4 (which should be able to trigger the bug) > > > and then try v6.14-rc4 + that series applied, to see if you can still trigger > > > the bug? > > > > Another patch that might be relevant: > > https://git.kernel.org/pub/scm/linux/kernel/git/torvalds/linux.git/commit/?id=e972b08b91ef48488bae9789f03cfedb148667fb > > > > Which fixes a use after delete in rq_qos_wake_function(). > > (We can see that the stack trace has rq_qos_wake_function() before > > getting stuck forever in rq_qos_wait()) > > > > Who knows what could go wrong when accessing a deleted entry, in the > > report there was a crash, but I could image other surprises :) > > The fix was first included in v6.12-rc4. > > > > > Hi Niklas, > > Thanks for the info. I have tried using v6.12-rc4 kernel to reproduce > the issue. Using the same repro binary, the issue still exists. Thanks a lot for your help with testing! The first series that I pointed to, which looks most likely to be related: https://lore.kernel.org/linux-block/20241014092934.53630-1-songmuchun@xxxxxxxxxxxxx/ Is only merged in: https://git.kernel.org/pub/scm/linux/kernel/git/axboe/linux-block.git/log/?h=for-6.13/block It is not included in v6.12-rc4. Would it please be possible for you to test with Jens's for-6.13/block branch? Kind regards, Niklas
