Re: [PATCH] io_uring: avoid page allocation warnings

From: Mark Rutland
Date: Wed May 01 2019 - 11:56:20 EST


On Wed, May 01, 2019 at 09:29:25AM -0600, Jens Axboe wrote:
> On 5/1/19 9:09 AM, Mark Rutland wrote:
> > I've manually minimized that to C below. AFAICT, that hits a leak, which
> > is what's triggering the OOM after the program is run a number of times
> > with the previously posted kvmalloc patch.
> >
> > Per /proc/meminfo, that memory isn't accounted anywhere.
> >
> >> Patch looks fine to me. Note
> >> that buffer registration is under the protection of RLIMIT_MEMLOCK.
> >> That's usually very limited for non-root, as root you can of course
> >> consume as much as you want and OOM the system.
> >
> > Sure.
> >
> > As above, it looks like there's a leak, regardless.
>
> The leak is that we're not releasing imu->bvec in case of error. I fixed
> a missing kfree -> kvfree as well in your patch, with this rolled up
> version it works for me.

That works for me too.

I'll fold that into v2, and send that out momentarily.

Thanks,
Mark.