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 67DC73A1E8C; Wed, 23 Sep 2026 08:35:38 +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=1790152548; cv=none; b=GOoPXhFShVB+umiIyz4pULshx2hXwr9Jjiui3DLmyBwjkJ3bOnPA1JReN9KvWHc/il4LghvWe/z0BjQh3B+4ld48kqMz11FBbRLx6n+npzgaAlb2wDA0PzDwdYHYfTYXAN2wuEF7ujdFMxdM0Zx7QsEQyms8cqvJoWGAHj/9v5Q= ARC-Message-Signature:i=1; a=rsa-sha256; d=subspace.kernel.org; s=arc-20240116; t=1790152548; c=relaxed/simple; bh=Kr/Xd9LH8Gk6I5VgZgmbq6oEqKwBzvwrjbCo2r0lK3c=; h=Message-ID:Date:MIME-Version:From:Subject:To:Cc:References: In-Reply-To:Content-Type; b=UKeONcx87YW+4h9ogVpwkxNU46/qtjrYXWl8NqhsnqQIyew+/+WygV66dO0PteM5YZRkwJ9yb2j9YfZ10L4BRk/d5Zp4BmK9NgcQ5zD/TdZTYPM3aASKFSjLKk7p+ROkSnBRxtEPl7eouxxFtHzaomfMvvSzSeC+o2c8Txoci3Y= ARC-Authentication-Results:i=1; smtp.subspace.kernel.org; dkim=pass (2048-bit key) header.d=kernel.org header.i=@kernel.org header.b=hdoPLl0T; arc=none smtp.client-ip=100.103.45.18 Authentication-Results: smtp.subspace.kernel.org; dkim=pass (2048-bit key) header.d=kernel.org header.i=@kernel.org header.b="hdoPLl0T" Received: by smtp.kernel.org (Postfix) with ESMTPSA id DFB3E1F000FF; Wed, 23 Sep 2026 08:35:33 +0000 (UTC) DKIM-Signature: v=1; a=rsa-sha256; c=relaxed/relaxed; d=kernel.org; s=k20260515; t=1790152535; bh=xcHmeC4HtsHnBaEvav6MT+VojyrSYCAIvDipmUfuBXE=; h=Date:From:Subject:To:Cc:References:In-Reply-To; b=hdoPLl0TqYLXQqCvf5YBTiDSDJIKXQdaVG4e4sLHTX71A2ba6BQnmYaNi+EpLma2j /3AzJw2IhmaXW5iOryUiGXHVoUIqfss11tG0e5KVEYi3K65SBjUv9Yml2EcWDXPgJr JOXbecpveSagsBvHtHKVE3kTqcvQbgXGfjkTdpdzY723aJsPouMaOzphc/6muaRyd6 EticdiAgJF5GkSdhOQUmCqiIpzDWKozTM9y8ZuLB2x4uPvovDtogoMEw1MUz+TMrJZ /5rCfZCS3NWYPMMDJV93nnq9QGFcaSoWHg8s6UQraWHViyBjhV8dlo5KkFKI/G/pJT zKKGxFt9gbZxQ== Message-ID: <55649a1b-a3f1-4e4f-a07d-416fbc0edfe0@kernel.org> Date: Wed, 23 Sep 2026 10:35:32 +0200 Precedence: bulk X-Mailing-List: linux-kernel@vger.kernel.org List-Id: List-Subscribe: List-Unsubscribe: MIME-Version: 1.0 User-Agent: Mozilla Thunderbird From: Hans Verkuil Subject: Re: [PATCH] media: vivid: check for NULL dev in vivid_probe() control setup To: Rohinthan , Mauro Carvalho Chehab Cc: linux-media@vger.kernel.org, linux-kernel@vger.kernel.org, syzbot+caaca441bae2799984d3@syzkaller.appspotmail.com References: <20260922125434.19361-1-rokinthanp03@gmail.com> Content-Language: en-US, nl In-Reply-To: <20260922125434.19361-1-rokinthanp03@gmail.com> Content-Type: text/plain; charset=UTF-8 Content-Transfer-Encoding: 7bit On 22/09/2026 14:54, Rohinthan wrote: > In vivid_probe(), after creating instances, the driver iterates > through vivid_devs[0..n_devs-1] to populate HDMI and S-Video > 'Connected To' controls. However, it dereferences dev->has_vid_out > without verifying that dev is non-NULL. > > If an instance fails during creation (or if devices race during > probe/remove), vivid_devs[i] remains NULL, causing a general > protection fault: > > Oops: general protection fault > KASAN: probably user-memory-access in range > [0x0000000000005f38-0x0000000000005f3f] > RIP: 0010:vivid_probe+0x579/0x10d0 > > Add NULL pointer checks in both loops in vivid_probe() before accessing > vivid_devs[i]. Also set .suppress_bind_attrs = true on > vivid_pdrv.driver to prevent concurrent sysfs bind/unbind operations > from triggering races. > > Fixes: d7c969f37515 ("media: vivid: Add 'Is Connected To' menu controls") > Reported-by: syzbot+caaca441bae2799984d3@syzkaller.appspotmail.com > Closes: https://syzkaller.appspot.com/bug?extid=caaca441bae2799984d3 > Signed-off-by: Rohinthan > --- > drivers/media/test-drivers/vivid/vivid-core.c | 19 +++++++++++++------ > 1 file changed, 13 insertions(+), 6 deletions(-) > > diff --git a/drivers/media/test-drivers/vivid/vivid-core.c b/drivers/media/test-drivers/vivid/vivid-core.c > index 62cfb5f..31a90ec 100644 > --- a/drivers/media/test-drivers/vivid/vivid-core.c > +++ b/drivers/media/test-drivers/vivid/vivid-core.c > @@ -2116,17 +2116,19 @@ static int vivid_probe(struct platform_device *pdev) > for (int i = 0; i < n_devs; i++) { > struct vivid_dev *dev = vivid_devs[i]; > > + if (!dev) > + continue; This can never happen, vivid_devsis always not-NULL for indices up to n_devs - 1. If there is a crash, then it is caused by something else. > if (!dev->has_vid_out) > continue; > for (int j = 0; j < dev->num_outputs && hdmi_count < MAX_MENU_ITEMS; ++j) { > if (dev->output_type[j] == HDMI) { > - vivid_ctrl_hdmi_to_output_instance[hdmi_count] = vivid_devs[i]; > + vivid_ctrl_hdmi_to_output_instance[hdmi_count] = dev; > vivid_ctrl_hdmi_to_output_index[hdmi_count++] = j; > } > } > for (int j = 0; j < dev->num_outputs && svid_count < MAX_MENU_ITEMS; ++j) { > if (dev->output_type[j] == SVID) { > - vivid_ctrl_svid_to_output_instance[svid_count] = vivid_devs[i]; > + vivid_ctrl_svid_to_output_instance[svid_count] = dev; > vivid_ctrl_svid_to_output_index[svid_count++] = j; > } > } > @@ -2134,13 +2136,17 @@ static int vivid_probe(struct platform_device *pdev) > hdmi_count = min(hdmi_count, MAX_MENU_ITEMS); > svid_count = min(svid_count, MAX_MENU_ITEMS); > for (int i = 0; i < n_devs; i++) { > - for (int j = 0; j < vivid_devs[i]->num_hdmi_inputs; j++) { > - struct v4l2_ctrl *c = vivid_devs[i]->ctrl_hdmi_to_output[j]; > + struct vivid_dev *dev = vivid_devs[i]; > + > + if (!dev) > + continue; > + for (int j = 0; j < dev->num_hdmi_inputs; j++) { > + struct v4l2_ctrl *c = dev->ctrl_hdmi_to_output[j]; > > v4l2_ctrl_modify_range(c, c->minimum, hdmi_count - 1, 0, c->default_value); > } > - for (int j = 0; j < vivid_devs[i]->num_svid_inputs; j++) { > - struct v4l2_ctrl *c = vivid_devs[i]->ctrl_svid_to_output[j]; > + for (int j = 0; j < dev->num_svid_inputs; j++) { > + struct v4l2_ctrl *c = dev->ctrl_svid_to_output[j]; > > v4l2_ctrl_modify_range(c, c->minimum, svid_count - 1, 0, c->default_value); > } > @@ -2240,6 +2246,7 @@ static struct platform_driver vivid_pdrv = { > .remove = vivid_remove, > .driver = { > .name = "vivid", > + .suppress_bind_attrs = true, Nack. We WANT vivid to be unbound. It is part of the regression tests. > }, > }; > Rejecting this patch. Regards, Hans