From: sashiko-bot@kernel.org
To: "Artem Novikov" <novart962@gmail.com>
Cc: linux-serial@vger.kernel.org
Subject: Re: [PATCH] tty: n_gsm: serialize mux configuration
Date: Tue, 10 Nov 2026 08:07:22 +0000 [thread overview]
Message-ID: <sashiko-outbox-206566@kernel.org> (raw)
In-Reply-To: <20261110075538.51452-1-novart962@gmail.com>
> From: Artem Novikov <naa@amicon.ru>
>
> Concurrent GSMIOC_SETCONF calls can both decide to restart the same mux.
> gsm_cleanup_mux() releases gsm->mutex before gsm_config() calls
> gsm_activate_mux(), so cleanup and activation from different calls can
> overlap. The activation paths can register the same gsmtty minors, and
> registration rollback can race with another registration or cleanup.
> GSMIOC_SETCONF_EXT can restart the mux through the same paths.
>
> A 5.10.246-syzkaller report shows a NULL dereference in the unregister
> path:
>
> KASAN: null-ptr-deref in range [0x0000000000000060-0x0000000000000067]
> RIP: 0010:cdev_del+0x22/0x90 fs/char_dev.c:596
> Call Trace:
> [ ... ]
> finish; independent muxes retain separate locks.
>
> Fixes: 01aecd917114 ("tty: n_gsm: fix tty registration before control channel open")
> Cc: stable@vger.kernel.org
> Signed-off-by: Artem Novikov <naa@amicon.ru>
Sashiko has reviewed this patch and found no issues.
--
Sashiko AI review · https://sashiko.dev/#/patchset/20261110075538.51452-1-novart962@gmail.com?part=1
next prev parent reply other threads:[~2026-11-10 8:07 UTC|newest]
Thread overview: 3+ messages / expand[flat|nested] mbox.gz Atom feed top
2026-11-10 7:55 [PATCH] tty: n_gsm: serialize mux configuration Artem Novikov
2026-11-10 8:07 ` sashiko-bot [this message]
2026-11-10 16:47 ` Greg KH
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