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From: Greg KH <gregkh@linuxfoundation.org>
To: Artem Novikov <novart962@gmail.com>
Cc: jirislaby@kernel.org, linux-serial@vger.kernel.org,
	linux-kernel@vger.kernel.org, stable@vger.kernel.org
Subject: Re: [PATCH] tty: n_gsm: serialize mux configuration
Date: Tue, 10 Nov 2026 11:47:46 -0500	[thread overview]
Message-ID: <2026111056-nerd-plunder-5aa5@gregkh> (raw)
In-Reply-To: <20261110075538.51452-1-novart962@gmail.com>

On Tue, Nov 10, 2026 at 10:55:38AM +0300, Artem Novikov wrote:
> 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:

Unless you have this hardware, and have tested it on that hardware, I
can't take any patches for this code, no matter how horrible you get
syzbot to abuse this driver (also that is a VERY old kernel tree, always
test Linus's latest.)

Please see the archives for why this is the policy here.

thanks,

greg k-h

      reply	other threads:[~2026-11-10 16:47 UTC|newest]

Thread overview: 2+ messages / expand[flat|nested]  mbox.gz  Atom feed  top
2026-11-10  7:55 Artem Novikov
2026-11-10 16:47 ` Greg KH [this message]

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