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Date:   Sun, 2 Oct 2022 20:05:56 +0200
From:   Michael Grzeschik <mgr@pengutronix.de>
To:     Guenter Roeck <linux@roeck-us.net>
Cc:     Laurent Pinchart <laurent.pinchart@ideasonboard.com>,
        Felipe Balbi <balbi@kernel.org>,
        Greg Kroah-Hartman <gregkh@linuxfoundation.org>,
        linux-usb@vger.kernel.org, linux-kernel@vger.kernel.org
Subject: Re: [PATCH] usb: gadget: uvc: Fix clearing of vdev
Message-ID: <20221002180556.GB19990@pengutronix.de>
References: <20221002174430.3065870-1-linux@roeck-us.net>
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Hi Guenter!

Thanks for the Patch.

On Sun, Oct 02, 2022 at 10:44:30AM -0700, Guenter Roeck wrote:
>Commit e4ce9ed835bc ("usb: gadget: uvc: ensure the vdev is unset")
>introduced code to clear the video device on video device registration.
>However, it uses sizeof(uvc->video) instead of sizeof(uvc->vdev) to clear
>uvc->vdev. This may result in the following build error.
>
>In function 'fortify_memset_chk',
>    inlined from 'uvc_register_video'
>    at drivers/usb/gadget/function/f_uvc.c:424:2:
>include/linux/fortify-string.h:301:25: error:
>	call to '__write_overflow_field' declared with attribute warning:
>		detected write beyond size of field
>
>The problem is exposed by commit 9b91a6523078 ("usb: gadget: uvc: increase
>worker prio to WQ_HIGHPRI") which increases the size of struct uvc_video.
>
>Fixes: e4ce9ed835bc ("usb: gadget: uvc: ensure the vdev is unset")
>Cc: Michael Grzeschik <m.grzeschik@pengutronix.de>
>Signed-off-by: Guenter Roeck <linux@roeck-us.net>
>---
> drivers/usb/gadget/function/f_uvc.c | 2 +-
> 1 file changed, 1 insertion(+), 1 deletion(-)
>
>diff --git a/drivers/usb/gadget/function/f_uvc.c b/drivers/usb/gadget/func=
tion/f_uvc.c
>index e6948cf8def3..836601227155 100644
>--- a/drivers/usb/gadget/function/f_uvc.c
>+++ b/drivers/usb/gadget/function/f_uvc.c
>@@ -421,7 +421,7 @@ uvc_register_video(struct uvc_device *uvc)
> 	int ret;
>
> 	/* TODO reference counting. */
>-	memset(&uvc->vdev, 0, sizeof(uvc->video));
>+	memset(&uvc->vdev, 0, sizeof(uvc->vdev));
> 	uvc->vdev.v4l2_dev =3D &uvc->v4l2_dev;
> 	uvc->vdev.v4l2_dev->dev =3D &cdev->gadget->dev;
> 	uvc->vdev.fops =3D &uvc_v4l2_fops;
>--=20
>2.36.2

This was already addressed by the following patch some days ago.

https://lore.kernel.org/linux-usb/202209290106.E6EFD95D4@keescook/T/#t

Thanks,
Michael

--=20
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