Re: [PATCH] sock: Fix sk_sleep return invalid pointer

[Paolo Abeni]

On Tue, 2023-08-22 at 20:44 +0800, eadavis@xxxxxxxx wrote:
> From: Edward AD <eadavis@xxxxxxxx>
> 
> The parameter sk_sleep(sk) passed in when calling prepare_to_wait may 
> return an invalid pointer due to nr-release reclaiming the sock.
> Here, schedule_timeout_interruptible is used to replace the combination 
> of 'prepare_to_wait, schedule, finish_wait' to solve the problem.
> 
> Reported-and-tested-by: syzbot+666c97e4686410e79649@xxxxxxxxxxxxxxxxxxxxxxxxx
> Signed-off-by: Edward AD <eadavis@xxxxxxxx>

This looks wrong. No syscall should race with sock_release(). It looks
like you are papering over the real issue.

As the reproducer shows a disconnect on an connected socket, I'm wild
guessing something alike 4faeee0cf8a5d88d63cdbc3bab124fb0e6aed08c
should be more appropriate.

Cheers,

Paolo