Mauro Carvalho Chehab a écrit :
Hi Thierry,
I am currently debugging the Trent's patch that makes a kernel oops and
I don't know why.
The usbvision_probe is called event if the device is not plugged, and
the kernel oops occurs on this piece of code:
model = devid->driver_info;
printk(KERN_INFO "%s: %s found\n", __FUNCTION__,
usbvision_device_data[model].ModelString);
Memory alignment problem ? Why this probe is called even if there is no
device plugged-in ?
Very weird. It shouldn't be called when no device is plugged...
By putting something like:
model = devid->driver_info;
if(model<0 || model >HPG_WINTV) {
printk(KERN_INFO "model out of bounds %d\n",model);
return -ENODEV;
} else printk(KERN_INFO "model is %d\n",model);
The problem disappeared...
A similar code is also present on em28xx. Anyway, it is better to have
this kind of protection. I've added a patch, based on yours, fixing the
bug. As you'd agreed, I've pushed the patches to master tree.
It is better, however, to check why it is calling the code, without a
valid USB ID, since it may mean a future trouble...
If I delete this line in the device_table:
{ USB_DEVICE(0xfff0, 0xfff0), .driver_info=DUMMY_DEVICE },
there is no more call to the usb probe function. But I think I will lose
the custom device facility.
I think these USB_DEVICE parameters are special ones indicating to usb
core that usbvision_probe must be called for unclaimed devices.
I plugged a new USB peripheral without having plugged the corresponding
driver, I got the "model out of bounds" message. printk should be
changed to a PDEBUG in order to deactivate this log by default (did it
in my repository).
Btw, I think we can also apply this one also:
diff -r 6b6805e3c76d linux/drivers/media/video/usbvision/usbvision-video.c
--- a/linux/drivers/media/video/usbvision/usbvision-video.c Sat Apr 14 15:17:08 2007 -0300
+++ b/linux/drivers/media/video/usbvision/usbvision-video.c Sat Apr 14 15:19:06 2007 -0300
@@ -1985,8 +1985,6 @@ static int __devinit usbvision_probe(str
return -ENODEV;
}
- usb_get_dev(dev);
-
if ((usbvision = usbvision_alloc(dev)) == NULL) {
err("%s: couldn't allocate USBVision struct", __FUNCTION__);
return -ENOMEM;
usb_get_dev() is already called previously on usbvision_probe.
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