This is a note to let you know that I've just added the patch titled
media: uvcvideo: Handle errors from calls to usb_string
to the 4.19-stable tree which can be found at:
http://www.kernel.org/git/?p=linux/kernel/git/stable/stable-queue.git;a=summary
The filename of the patch is:
media-uvcvideo-handle-errors-from-calls-to-usb_strin.patch
and it can be found in the queue-4.19 subdirectory.
If you, or anyone else, feels it should not be added to the stable tree,
please let <stable@xxxxxxxxxxxxxxx> know about it.
commit 073051cbe0b1b3a4cb64bc864659c1a9de43b9fc
Author: Guenter Roeck <linux@xxxxxxxxxxxx>
Date: Tue Oct 25 16:41:01 2022 +0200
media: uvcvideo: Handle errors from calls to usb_string
[ Upstream commit 4867bb590ae445bcfaa711a86b603c97e94574b3 ]
On a Webcam from Quanta, we see the following error.
usb 3-5: New USB device found, idVendor=0408, idProduct=30d2, bcdDevice= 0.03
usb 3-5: New USB device strings: Mfr=3, Product=1, SerialNumber=2
usb 3-5: Product: USB2.0 HD UVC WebCam
usb 3-5: Manufacturer: Quanta
usb 3-5: SerialNumber: 0x0001
...
uvcvideo: Found UVC 1.10 device USB2.0 HD UVC WebCam (0408:30d2)
uvcvideo: Failed to initialize entity for entity 5
uvcvideo: Failed to register entities (-22).
The Webcam reports an entity of type UVC_VC_EXTENSION_UNIT. It reports a
string index of '7' associated with that entity. The attempt to read that
string from the camera fails with error -32 (-EPIPE). usb_string() returns
that error, but it is ignored. As result, the entity name is empty. This
later causes v4l2_device_register_subdev() to return -EINVAL, and no
entities are registered as result.
While this appears to be a firmware problem with the camera, the kernel
should still handle the situation gracefully. To do that, check the return
value from usb_string(). If it reports an error, assign the entity's
default name.
Signed-off-by: Guenter Roeck <linux@xxxxxxxxxxxx>
Reviewed-by: Laurent Pinchart <laurent.pinchart@xxxxxxxxxxxxxxxx>
Signed-off-by: Laurent Pinchart <laurent.pinchart@xxxxxxxxxxxxxxxx>
Signed-off-by: Sasha Levin <sashal@xxxxxxxxxx>
diff --git a/drivers/media/usb/uvc/uvc_driver.c b/drivers/media/usb/uvc/uvc_driver.c
index 998ce712978ae..775d677206484 100644
--- a/drivers/media/usb/uvc/uvc_driver.c
+++ b/drivers/media/usb/uvc/uvc_driver.c
@@ -1033,10 +1033,8 @@ static int uvc_parse_vendor_control(struct uvc_device *dev,
+ n;
memcpy(unit->extension.bmControls, &buffer[23+p], 2*n);
- if (buffer[24+p+2*n] != 0)
- usb_string(udev, buffer[24+p+2*n], unit->name,
- sizeof(unit->name));
- else
+ if (buffer[24+p+2*n] == 0 ||
+ usb_string(udev, buffer[24+p+2*n], unit->name, sizeof(unit->name)) < 0)
sprintf(unit->name, "Extension %u", buffer[3]);
list_add_tail(&unit->list, &dev->entities);
@@ -1161,15 +1159,15 @@ static int uvc_parse_standard_control(struct uvc_device *dev,
memcpy(term->media.bmTransportModes, &buffer[10+n], p);
}
- if (buffer[7] != 0)
- usb_string(udev, buffer[7], term->name,
- sizeof(term->name));
- else if (UVC_ENTITY_TYPE(term) == UVC_ITT_CAMERA)
- sprintf(term->name, "Camera %u", buffer[3]);
- else if (UVC_ENTITY_TYPE(term) == UVC_ITT_MEDIA_TRANSPORT_INPUT)
- sprintf(term->name, "Media %u", buffer[3]);
- else
- sprintf(term->name, "Input %u", buffer[3]);
+ if (buffer[7] == 0 ||
+ usb_string(udev, buffer[7], term->name, sizeof(term->name)) < 0) {
+ if (UVC_ENTITY_TYPE(term) == UVC_ITT_CAMERA)
+ sprintf(term->name, "Camera %u", buffer[3]);
+ if (UVC_ENTITY_TYPE(term) == UVC_ITT_MEDIA_TRANSPORT_INPUT)
+ sprintf(term->name, "Media %u", buffer[3]);
+ else
+ sprintf(term->name, "Input %u", buffer[3]);
+ }
list_add_tail(&term->list, &dev->entities);
break;
@@ -1201,10 +1199,8 @@ static int uvc_parse_standard_control(struct uvc_device *dev,
memcpy(term->baSourceID, &buffer[7], 1);
- if (buffer[8] != 0)
- usb_string(udev, buffer[8], term->name,
- sizeof(term->name));
- else
+ if (buffer[8] == 0 ||
+ usb_string(udev, buffer[8], term->name, sizeof(term->name)) < 0)
sprintf(term->name, "Output %u", buffer[3]);
list_add_tail(&term->list, &dev->entities);
@@ -1226,10 +1222,8 @@ static int uvc_parse_standard_control(struct uvc_device *dev,
memcpy(unit->baSourceID, &buffer[5], p);
- if (buffer[5+p] != 0)
- usb_string(udev, buffer[5+p], unit->name,
- sizeof(unit->name));
- else
+ if (buffer[5+p] == 0 ||
+ usb_string(udev, buffer[5+p], unit->name, sizeof(unit->name)) < 0)
sprintf(unit->name, "Selector %u", buffer[3]);
list_add_tail(&unit->list, &dev->entities);
@@ -1259,10 +1253,8 @@ static int uvc_parse_standard_control(struct uvc_device *dev,
if (dev->uvc_version >= 0x0110)
unit->processing.bmVideoStandards = buffer[9+n];
- if (buffer[8+n] != 0)
- usb_string(udev, buffer[8+n], unit->name,
- sizeof(unit->name));
- else
+ if (buffer[8+n] == 0 ||
+ usb_string(udev, buffer[8+n], unit->name, sizeof(unit->name)) < 0)
sprintf(unit->name, "Processing %u", buffer[3]);
list_add_tail(&unit->list, &dev->entities);
@@ -1290,10 +1282,8 @@ static int uvc_parse_standard_control(struct uvc_device *dev,
unit->extension.bmControls = (u8 *)unit + sizeof(*unit);
memcpy(unit->extension.bmControls, &buffer[23+p], n);
- if (buffer[23+p+n] != 0)
- usb_string(udev, buffer[23+p+n], unit->name,
- sizeof(unit->name));
- else
+ if (buffer[23+p+n] == 0 ||
+ usb_string(udev, buffer[23+p+n], unit->name, sizeof(unit->name)) < 0)
sprintf(unit->name, "Extension %u", buffer[3]);
list_add_tail(&unit->list, &dev->entities);
