From mboxrd@z Thu Jan 1 00:00:00 1970 Authentication-Results: smtp.subspace.kernel.org; arc=none smtp.remote-ip=100.103.45.18 ARC-Seal: i=1; d=subspace.kernel.org; s=arc20261015; a=rsa-sha256; cv=none; t=1794329270; b=lV4R+gLsn3B4aPsCmfPw6wP3RzdOgusa4bunvGVtPdHsZhH6lZm8n2bLzDlnsv7dNtRK 9hGq8PRv88zcqXNSTTmXzMx74ujf7GX3DmWMGm6gsOwapqd3+7kvV8YhqBKHXhUy5RlV6 xytSdtOLqR89zYtCGyMjgOPHJKIyJTnyqDo4OcHGub2XH8BCVMOHsVn9hApeHIRr+7ySh b8H+gSIGyYdjBriW7Y6iUcyT9xo+yOT2szO83Yq01cpUTUFGVxwbWG6m0X+gSkzedPfdj xQWZYpZD/h5mJOgPdyQzYWBYv9OQla7NcHRgt4d/ScJ2uxYSI+rUABULI3HoMFvpVIw== ARC-Message-Signature: i=1; d=subspace.kernel.org; s=arc20261015; a=rsa-sha256; c=relaxed/relaxed; t=1794329270; h=Received:DKIM-Signature:Date:From:To:Cc:Subject:Message-ID: References:MIME-Version:Content-Type:Content-Disposition:In-Reply-To; bh=ebmyXy0NycGoNtKM2+8c0u716/QOVyCgQosp484QW/w=; b=QffUlTuo8J4srDqmYZID995MaWs9YREHLmrQYhbHiJwOswSIl90tfLfctqF2vpN5gHwC M7Gc1aYno6/aPDJRnKr2MoofYyyh6DbwXSK0s8orz3N9brHcUjinl8MlWCw+d4JXQQXvt 0uwrOh2bwSDpwoev+hi+fs32woIVzP7OI03bLpMX6AIRb1TRzIsWwGrfIHTFZvZBgy+ug DPZfvVMmIDVtBcfaoFD8ykRRXGIaxiJAiq9GNrrZTrnXK8Taenss7Uspz+5Y8JbkwAiqn NHFsRcjSE8+d3EDBzCvJVCEg6iJaD9i12EpAYV+cG/OFUKnHjG+62ly/i0tI7oSxnCg== ARC-Authentication-Results: i=1; smtp.subspace.kernel.org; dkim=pass header.d=linuxfoundation.org header.i=@linuxfoundation.org header.a=rsa-sha256 header.s=korg header.b=b3TbTLxJ; arc=none smtp.remote-ip=100.103.45.18 Received: from smtp.kernel.org (quasi.space.kernel.org [100.103.45.18]) (using TLSv1.3 with cipher TLS_AES_256_GCM_SHA384 (256/256 bits) key-exchange X25519 server-signature ECDSA (prime256v1)) (No client certificate requested) by smtp.subspace.kernel.org (Postfix) with ESMTPS id D0B14606A32A; Tue, 10 Nov 2026 16:47:49 +0000 (UTC) Authentication-Results: smtp.subspace.kernel.org; dkim=pass (1024-bit key, unprotected) header.d=linuxfoundation.org header.i=@linuxfoundation.org header.a=rsa-sha256 header.s=korg header.b=b3TbTLxJ Received: by smtp.kernel.org (Postfix) with ESMTPSA id D37451F008A1; Tue, 10 Nov 2026 16:47:48 +0000 (UTC) DKIM-Signature: v=1; a=rsa-sha256; c=relaxed/relaxed; d=linuxfoundation.org; s=korg; t=1794329269; bh=ebmyXy0NycGoNtKM2+8c0u716/QOVyCgQosp484QW/w=; h=Date:From:To:Cc:Subject:References:In-Reply-To; b=b3TbTLxJaEo1DMI3T/reGwVTLPNZJAcOQVRfhRvkG4cmykc1VKNyR8wuAyMFP/HYL ipvMwqIqzlsD6Vm4Ns010eY+fqDewC8T6mmgabn4JIBYjF/6+PXZpCNtoqwlP1gAyg dDNExUKVx5rW4flE7AikZH2IJkFaVLgGf6sUMwhs= Date: Tue, 10 Nov 2026 11:47:46 -0500 From: Greg KH To: Artem Novikov 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 Message-ID: <2026111056-nerd-plunder-5aa5@gregkh> References: <20261110075538.51452-1-novart962@gmail.com> X-Mailing-List: linux-kernel@vger.kernel.org List-Id: List-Post: List-Help: List-Subscribe: List-Unsubscribe: List-Owner: Precedence: list MIME-Version: 1.0 Content-Type: text/plain; charset=us-ascii Content-Disposition: inline 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 > > 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