Re: [PATCH for-next] io_uring: fix not released cached task refs

[Lukas Bulwahn <lukas.bulwahn@gmail.com>]

On Sun, Jan 9, 2022 at 5:23 PM Jens Axboe <axboe@kernel.dk> wrote:
>
> On Sun, 9 Jan 2022 00:53:22 +0000, Pavel Begunkov wrote:
> > tctx_task_work() may get run after io_uring cancellation and so there
> > will be no one to put cached in tctx task refs that may have been added
> > back by tw handlers using inline completion infra, Call
> > io_uring_drop_tctx_refs() at the end of the main tw handler to release
> > them.
> >
> >
> > [...]
>
> Applied, thanks!
>
> [1/1] io_uring: fix not released cached task refs
>       commit: 3cc7fdb9f90a25ae92250bf9e6cf3b9556b230e9
>

The memory leak, reported in
https://lore.kernel.org/all/CAKXUXMzHUi3q4K-OpiBKyMAsQ2K=FOsVzULC76v05nCUKNCA+Q@mail.gmail.com/:

    - does     trigger on next-20220107.

    - does NOT trigger on next-20220107 + cherry-pick
3cc7fdb9f90a25ae92250bf9e6cf3b9556b230e9.

    - does NOT trigger on next-20220110, which already includes commit
3cc7fdb9f90a25ae92250bf9e6cf3b9556b230e9.


So, with that I think this patch resolves the reported memory leak for good:

Tested-by: Lukas Bulwahn <lukas.bulwahn@gmail.com>

Pavel, thanks for the quick fix.

I guess that the patch has already landed in linux-next, so the tag
above will not be applied to the commit, but is only for our own
historic reference.

Lukas