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

[Pavel Begunkov]

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.

--
Pavel Begunkov