Re: [PATCH] net/tcp_sigpool: Use kref_get_unless_zero()

[Eric Dumazet]

On Fri, Dec 22, 2023 at 2:14 AM Dmitry Safonov <dima@xxxxxxxxxx> wrote:
>
> The freeing and re-allocation of algorithm are protected by cpool_mutex,
> so it doesn't fix an actual use-after-free, but avoids a deserved
> refcount_warn_saturate() warning.
>
> A trivial fix for the racy behavior.
>
> Fixes: 8c73b26315aa ("net/tcp: Prepare tcp_md5sig_pool for TCP-AO")
> Suggested-by: Eric Dumazet <edumazet@xxxxxxxxxx>
> Signed-off-by: Dmitry Safonov <dima@xxxxxxxxxx>

Reported-by: syzbot <syzkaller@xxxxxxxxxxxxxxxx>
Reviewed-by: Eric Dumazet <edumazet@xxxxxxxxxx>