linux-kernel - Re: [PATCH v1] io_uring: Fix memory leak if file setup fails.

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Message-ID: <8f8d07c1-9276-df86-f1dc-3d272d4ab91d@kernel.dk>
Date:   Fri, 29 Apr 2022 06:47:55 -0600
From:   Jens Axboe <axboe@...nel.dk>
To:     Noah Goldstein <goldstein.w.n@...il.com>
Cc:     asml.silence@...il.com, io-uring@...r.kernel.org,
        linux-kernel@...r.kernel.org
Subject: Re: [PATCH v1] io_uring: Fix memory leak if file setup fails.

On 4/28/22 6:42 PM, Noah Goldstein wrote:
> If `get_unused_fd_flags` files fails (either in setting up `ctx` as
> `tctx->last` or `get_unused_fd_flags`) `ctx` will never be freed.

There's a comment there telling you why, the fput will end up
releasing it just like it would when an application closes it.

> I very well may be missing something (or there may be a double
> free if the failure is after `get_unused_fd_flags`) but looks
> to me to be a memory leak.

Have you tried synthetically reproducing the two failures you're
thinking of and tracing cleanup?

-- 
Jens Axboe