Re: Stable backport (was "Re: PROBLEM: io_uring hang causing uninterruptible sleep state on 6.6.59")

[Greg Kroah-Hartman <gregkh@linuxfoundation.org>]

On Sun, Nov 03, 2024 at 07:38:30PM -0700, Jens Axboe wrote:
> On 11/3/24 5:06 PM, Jens Axboe wrote:
> > On 11/3/24 5:01 PM, Keith Busch wrote:
> >> On Sun, Nov 03, 2024 at 04:53:27PM -0700, Jens Axboe wrote:
> >>> On 11/3/24 4:47 PM, Andrew Marshall wrote:
> >>>> I identified f4ce3b5d26ce149e77e6b8e8f2058aa80e5b034e as the likely
> >>>> problematic commit simply by browsing git log. As indicated above;
> >>>> reverting that atop 6.6.59 results in success. Since it is passing on
> >>>> 6.11.6, I suspect there is some missing backport to 6.6.x, or some
> >>>> other semantic merge conflict. Unfortunately I do not have a compact,
> >>>> minimal reproducer, but can provide my large one (it is testing a
> >>>> larger build process in a VM) if needed?there are some additional
> >>>> details in the above-linked downstream bug report, though. I hope that
> >>>> having identified the problematic commit is enough for someone with
> >>>> more context to go off of. Happy to provide more information if
> >>>> needed.
> >>>
> >>> Don't worry about not having a reproducer, having the backport commit
> >>> pin pointed will do just fine. I'll take a look at this.
> >>
> >> I think stable is missing:
> >>
> >>   6b231248e97fc3 ("io_uring: consolidate overflow flushing")
> > 
> > I think you need to go back further than that, this one already
> > unconditionally holds ->uring_lock around overflow flushing...
> 
> Took a look, it's this one:
> 
> commit 8d09a88ef9d3cb7d21d45c39b7b7c31298d23998
> Author: Pavel Begunkov <asml.silence@gmail.com>
> Date:   Wed Apr 10 02:26:54 2024 +0100
> 
>     io_uring: always lock __io_cqring_overflow_flush
> 
> Greg/stable, can you pick this one for 6.6-stable? It picks
> cleanly.
> 
> For 6.1, which is the other stable of that age that has the backport,
> the attached patch will do the trick.
> 
> With that, I believe it should be sorted. Hopefully that can make
> 6.6.60 and 6.1.116.

Now queued up, thanks.

greg k-h