From mboxrd@z Thu Jan 1 00:00:00 1970 Received: from smtp.kernel.org (aws-us-west-2-korg-mail-alma10-1.taild15c8.ts.net [100.103.45.18]) (using TLSv1.2 with cipher ECDHE-RSA-AES256-GCM-SHA384 (256/256 bits)) (No client certificate requested) by smtp.subspace.kernel.org (Postfix) with ESMTPS id B9C9A2E285C; Sat, 12 Sep 2026 14:05:38 +0000 (UTC) Authentication-Results: smtp.subspace.kernel.org; arc=none smtp.client-ip=100.103.45.18 ARC-Seal:i=1; a=rsa-sha256; d=subspace.kernel.org; s=arc-20240116; t=1789221939; cv=none; b=YBJU4EH5zVFjwfbrdVo8fFL6tuYmn/1qI2cyk7HI1tD91z8j2v63+YpoIxgqyOn6zrrFQU5v+2gYzqzOdmn89E3+x8VcHKFVtQPAYrklFrFXVtl63znaXeOUDWJd0iOvfh1goH9Kms/pw2ZBj9J+z4pW+oPkGSFLuq7HnzwBxVI= ARC-Message-Signature:i=1; a=rsa-sha256; d=subspace.kernel.org; s=arc-20240116; t=1789221939; c=relaxed/simple; bh=cRrN3I3y0pd0I1DYuxWAhVQCtqxLtQRHk072ogKn0g4=; h=From:To:Cc:Subject:Date:Message-ID:In-Reply-To:References: MIME-Version; b=uAh0tt3i1eqzbYOIVQdvn/ryVnYhBvjkFSNH7zJx4yKr5iuJcjY37JKE9smOdy73Sz5uRhVSwe9VHK5q1Jd5XDrG/163Rpz0YZxEbuZ9m4ww3c9wdZZINwHkCeMc4JLjB2+v2dI5uAmZS3HqbmJLUHs25ddygy4lLPJUXvENKIM= ARC-Authentication-Results:i=1; smtp.subspace.kernel.org; dkim=pass (1024-bit key) header.d=linuxfoundation.org header.i=@linuxfoundation.org header.b=jfeEwhKu; arc=none smtp.client-ip=100.103.45.18 Authentication-Results: smtp.subspace.kernel.org; dkim=pass (1024-bit key) header.d=linuxfoundation.org header.i=@linuxfoundation.org header.b="jfeEwhKu" Received: by smtp.kernel.org (Postfix) with ESMTPSA id 73A081F000FF; Sat, 12 Sep 2026 14:05:37 +0000 (UTC) DKIM-Signature: v=1; a=rsa-sha256; c=relaxed/relaxed; d=linuxfoundation.org; s=korg; t=1789221938; bh=gIddvwXAObSjJkJ4MvwWPjc9OPTJP3vIJig03GQKWLk=; h=From:To:Cc:Subject:Date:In-Reply-To:References; b=jfeEwhKu5H3fn2GRE/3QZXEtfNdMv9D0o7ujmOdBIMCLzUe1en4euET2I/rcVhEvD Pb6bJm1DKwa5RWWl9Wtamzv3yRtHW0/qWGm7Ub7RFs2cH4edg3sOUwuoJipvS6aBxD 3URm/ktssQ8CXDBmmuqgW5wRkjCV1HIXuUG8YeBo= From: Greg Kroah-Hartman To: stable@vger.kernel.org Cc: Greg Kroah-Hartman , patches@lists.linux.dev, Hans Verkuil , Valery Borovsky Subject: [PATCH 6.6 0441/1424] media: airspy: use vb2_video_unregister_device() on disconnect to fix NULL deref Date: Sat, 12 Sep 2026 08:47:53 +0200 Message-ID: <20260912065617.161184116@linuxfoundation.org> X-Mailer: git-send-email 2.55.0 In-Reply-To: <20260912065607.279695368@linuxfoundation.org> References: <20260912065607.279695368@linuxfoundation.org> User-Agent: quilt/0.69 X-stable: review X-Patchwork-Hint: ignore Precedence: bulk X-Mailing-List: patches@lists.linux.dev List-Id: List-Subscribe: List-Unsubscribe: MIME-Version: 1.0 Content-Transfer-Encoding: 8bit 6.6-stable review patch. If anyone has any objections, please let me know. ------------------ From: Valery Borovsky commit 2f378dc45e685fc825d2dd08e7864666d6fcc009 upstream. airspy_disconnect() clears s->udev under v4l2_lock, but airspy_stop_streaming() unconditionally calls airspy_ctrl_msg() and airspy_free_stream_bufs() afterwards. If a streaming user closes the device after disconnect, stop_streaming() runs and dereferences the NULL s->udev: airspy_stop_streaming() airspy_ctrl_msg(s, CMD_RECEIVER_MODE, 0, 0, NULL, 0) usb_sndctrlpipe(s->udev, 0) /* NULL deref */ airspy_free_stream_bufs(s) usb_free_coherent(s->udev, ...) /* NULL deref */ The airspy driver uses vb2_fop_release() in its file_operations, so replace video_unregister_device(&s->vdev) with vb2_video_unregister_device(&s->vdev) and move it before clearing s->udev. vb2_video_unregister_device() releases the vb2 queue, which synchronously runs airspy_stop_streaming() if streaming is active, so the URBs, coherent DMA stream buffers and the hardware stop control message all execute while s->udev is still valid. vb2_video_unregister_device() locks vdev->queue->lock (vb_queue_lock) internally, and stop_streaming() locks v4l2_lock, so the previous outer mutex_lock(&s->vb_queue_lock) / mutex_lock(&s->v4l2_lock) pair around the unregister sequence would self-deadlock and has been removed. A short v4l2_lock critical section around s->udev = NULL remains so any ioctl path that still holds the file descriptor sees coherent state. Issue identified by automated review of the INV-003 series at https://sashiko.dev/ Fixes: 634fe5033951 ("[media] airspy: AirSpy SDR driver") Cc: stable@vger.kernel.org Suggested-by: Hans Verkuil Signed-off-by: Valery Borovsky Signed-off-by: Hans Verkuil Signed-off-by: Greg Kroah-Hartman --- drivers/media/usb/airspy/airspy.c | 17 ++++++++++++----- 1 file changed, 12 insertions(+), 5 deletions(-) --- a/drivers/media/usb/airspy/airspy.c +++ b/drivers/media/usb/airspy/airspy.c @@ -464,14 +464,21 @@ static void airspy_disconnect(struct usb dev_dbg(s->dev, "\n"); - mutex_lock(&s->vb_queue_lock); + /* + * vb2_video_unregister_device() releases the vb2 queue, which + * triggers airspy_stop_streaming() if streaming is active. + * stop_streaming() dereferences s->udev via airspy_ctrl_msg() and + * airspy_free_stream_bufs(), so it must run before s->udev is + * cleared. vb2_video_unregister_device() locks vb_queue_lock + * internally and stop_streaming() locks v4l2_lock, so neither may + * be held by the caller. + */ + v4l2_device_disconnect(&s->v4l2_dev); + vb2_video_unregister_device(&s->vdev); + mutex_lock(&s->v4l2_lock); - /* No need to keep the urbs around after disconnection */ s->udev = NULL; - v4l2_device_disconnect(&s->v4l2_dev); - video_unregister_device(&s->vdev); mutex_unlock(&s->v4l2_lock); - mutex_unlock(&s->vb_queue_lock); v4l2_device_put(&s->v4l2_dev); }