From mboxrd@z Thu Jan 1 00:00:00 1970 Received: from extorris.mess.org (extorris.mess.org [92.243.27.206]) (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 4D580471D02; Fri, 11 Sep 2026 08:45:19 +0000 (UTC) Authentication-Results: smtp.subspace.kernel.org; arc=none smtp.client-ip=92.243.27.206 ARC-Seal:i=1; a=rsa-sha256; d=subspace.kernel.org; s=arc-20240116; t=1789116324; cv=none; b=rq5/vuzB+zAE39GDSsVahOGLZ8dv+gEv0Welj6qGfwK4CWOmKneCk7QRlaPXKzq4JGjXifIRjQqolYB9WwhwVMGH2jGEt2SUXACskf7HAXVlMSuQufRswXCZZGHorJQqPb90K7PSUFLreX58cqz9Z4QIOJsKoBUgDmn96t3uxq8= ARC-Message-Signature:i=1; a=rsa-sha256; d=subspace.kernel.org; s=arc-20240116; t=1789116324; c=relaxed/simple; bh=FVOn9eVfExPih1H3h9rhcV07hrmPKdVvx1JUdO6nt+w=; h=Date:From:To:Cc:Subject:Message-ID:References:MIME-Version: Content-Type:Content-Disposition:In-Reply-To; b=Xc075Vl1g0vp4XaaWZ13KY+JY3zU3fbHdQtOjYAm6UOZWL/IRLCfRS7nLjsuMPmvSCShHmFKzHGtM5jm9Ww5gs2vjSi9Mva9NzKvnJ6WcjgHmpyG+rPB/3bscn/nmaPdJAKdtOjPoVjgiI+qGCjurUKnyof0g4dGjnfIsrOQ/D0= ARC-Authentication-Results:i=1; smtp.subspace.kernel.org; dmarc=pass (p=none dis=none) header.from=mess.org; spf=pass smtp.mailfrom=mess.org; dkim=pass (2048-bit key) header.d=mess.org header.i=@mess.org header.b=EMovzk/G; arc=none smtp.client-ip=92.243.27.206 Authentication-Results: smtp.subspace.kernel.org; dmarc=pass (p=none dis=none) header.from=mess.org Authentication-Results: smtp.subspace.kernel.org; spf=pass smtp.mailfrom=mess.org Authentication-Results: smtp.subspace.kernel.org; dkim=pass (2048-bit key) header.d=mess.org header.i=@mess.org header.b="EMovzk/G" DKIM-Signature: v=1; a=rsa-sha256; c=relaxed/simple; d=mess.org; s=2020; t=1789116316; bh=FVOn9eVfExPih1H3h9rhcV07hrmPKdVvx1JUdO6nt+w=; h=Date:From:To:Cc:Subject:References:In-Reply-To:From; b=EMovzk/GPMARYZT55zqB0h151zATgKRoNilkMVULMebzQHoNBQ7dG06rAzQLU4Zp0 YdD3/dUaI1yAy3c83QUjSx1IRtsVlLNNXTOT7uc45GPbUO7JDdBS6nP9cQJzKspFLF PEpcIAzmeqR0/xp1O1And5+OPNSxOAjZffl0ZBKfyM3DVhCiyAp2DLcvkXFyEs9qwo aAyp9yRJSricEPFLrW6Zg48aDFSkGcBy61378kkWF6ewIT5Zhw+roNjrZPAb1aox7S rUYZcx9u1T6nLNvA00GbN+VZ2AaXLzm7WbNT0sL5cRbTJ+BwzMH4CDt6C/CI+gRKrq j53i7v2673ksw== Received: by extorris.mess.org (Postfix, from userid 1001) id E962341444; Fri, 11 Sep 2026 09:45:16 +0100 (BST) Date: Fri, 11 Sep 2026 09:45:16 +0100 From: Sean Young To: Hans Verkuil Cc: linux-media@vger.kernel.org, Mauro Carvalho Chehab , Patrice Chotard , Rik van Riel , stable@vger.kernel.org, linux-kernel@vger.kernel.org Subject: Re: [PATCH v4 01/19] media: rc: Ensure registered is cleared in error path Message-ID: References: <10c85f87-85db-4ee9-ab80-edbd30f3c95e@kernel.org> Precedence: bulk X-Mailing-List: linux-media@vger.kernel.org List-Id: List-Subscribe: List-Unsubscribe: MIME-Version: 1.0 Content-Type: text/plain; charset=us-ascii Content-Disposition: inline In-Reply-To: <10c85f87-85db-4ee9-ab80-edbd30f3c95e@kernel.org> On Fri, Sep 11, 2026 at 09:53:10AM +0200, Hans Verkuil wrote: > On 08/09/2026 17:51, Sean Young wrote: > > If rc_register_device() fails, ensure that registered is not set to true. > > If lirc_register() succeeded, then userspace could have an open file > > descriptor open. This leads to a use-after-free. > > > > Fixes: dccc0c3ddf8f ("media: rc: fix race between unregister and urb/irq callbacks") > > Signed-off-by: Sean Young > > Cc: stable@vger.kernel.org > > --- > > drivers/media/rc/rc-main.c | 5 ++++- > > 1 file changed, 4 insertions(+), 1 deletion(-) > > > > diff --git a/drivers/media/rc/rc-main.c b/drivers/media/rc/rc-main.c > > index d93e98189c1a..1f99540456f1 100644 > > --- a/drivers/media/rc/rc-main.c > > +++ b/drivers/media/rc/rc-main.c > > @@ -1934,7 +1934,8 @@ int rc_register_device(struct rc_dev *dev) > > goto out_raw; > > } > > > > - dev->registered = true; > > + scoped_guard(mutex, &dev->lock) > > + dev->registered = true; > > Is the guard actually needed? Yes, we read registered under lock in e.g. in lirc_open(). It s racey without. > > rc = device_add(&dev->dev); > > if (rc) > > @@ -1982,6 +1983,8 @@ int rc_register_device(struct rc_dev *dev) > > out_dev: > > device_del(&dev->dev); > > out_rx_free: > > + scoped_guard(mutex, &dev->lock) > > + dev->registered = false; > > Same question here. I think the real fix is setting dev->registered to > false, but I'm not sure the guard makes a difference. > > The commit log mentions nothing about that change either. You are right, the commit message needs to mention this. Sean