Re: Observation of a memory leak with commit e98e49b2bbf7 ("io_uring: extend task put optimisations")

[Pavel Begunkov]

On 1/7/22 16:22, Pavel Begunkov wrote:
> On 1/7/22 15:00, Lukas Bulwahn wrote:
> > Dear Pavel, dear Jens,
> >
> > In our syzkaller instance running on linux-next,
> > https://elisa-builder-00.iol.unh.edu/syzkaller-next/, we have been
> > observing a memory leak in copy_process for quite some time.
> >
> > It is reproducible on v5.15-rc1, v5.15, v5.16-rc8 and next-20220106:
> >
> > https://elisa-builder-00.iol.unh.edu/syzkaller-next/crash?id=1169da08a3e72457301987b70bcce62f0f49bdbb
> >
> > So, it is in mainline, was released and has not been fixed in linux-next yet.
> >
> > As syzkaller also provides a reproducer, we bisected this memory leak
> > to be introduced with commit e98e49b2bbf7 ("io_uring: extend task put
> > optimisations").
> >
> > Could you please have a look how your commit introduces this memory
> > leak? We will gladly support testing your fix in case help is needed.
>
> Thanks for letting know
> I think I know what it is, will get back later.

https://lore.kernel.org/io-uring/69f226b35fbdb996ab799a8bbc1c06bf634ccec1.1641688805.git.asml.silence@xxxxxxxxx

Should fix it, tested with the repro

--
Pavel Begunkov