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SubjectRe: [PATCH] tty: n_gsm: add missing tty_kref_put
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On 09. 11. 21, 11:39, Pavel Skripkin wrote:
> My local syzbot instance hit memory leak in gsmld_attach_gsm(). The
> reproducer injects allocation failure in tty_register_device(). After
> this error only previous tty_register_device() calls unwinded, but not
> tty_kref_get().
>
> It leads to tty_struct leak, because ->close() won't be called in case
> of ->open() failure and nothing puts tty reference.

I don't have time to check the n_gsm case now (like: are you talking
about tty->open/close or file_ops->open/close -- they behave
differently), but tty definitely calls close even if open fails.

> Fixes: 0a360e8b65d6 ("tty: n_gsm: check error while registering tty devices")
> Signed-off-by: Pavel Skripkin <paskripkin@gmail.com>
> ---
> drivers/tty/n_gsm.c | 2 ++
> 1 file changed, 2 insertions(+)
>
> diff --git a/drivers/tty/n_gsm.c b/drivers/tty/n_gsm.c
> index 1d92d2a84889..1cc3aec17d2d 100644
> --- a/drivers/tty/n_gsm.c
> +++ b/drivers/tty/n_gsm.c
> @@ -2394,6 +2394,8 @@ static int gsmld_attach_gsm(struct tty_struct *tty, struct gsm_mux *gsm)
> for (i--; i >= 1; i--)
> tty_unregister_device(gsm_tty_driver,
> base + i);
> +
> + tty_kref_put(gsm->tty);
> return PTR_ERR(dev);
> }
> }
>


--
js
suse labs

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