Re: [PATCH] modpost: detect unterminated device id lists

[Andrew Morton]

On Mon, 17 Sep 2007 05:54:45 +0530 "Satyam Sharma" <satyam.sharma@xxxxxxxxx> wrote:

> On 9/17/07, Andrew Morton <akpm@xxxxxxxxxxxxxxxxxxxx> wrote:
> > On Wed, 12 Sep 2007 17:49:37 -0700 Kees Cook <kees@xxxxxxxxxx> wrote:
> >
> > > This patch against 2.6.23-rc6 will cause modpost to fail if any device
> > > id lists are incorrectly terminated, after reporting the offender.
> >
> > I'm getting this:
> >
> > rusb2/pvrusb2: struct usb_device_id is 20 bytes.  The last of 3 is:
> > 0x03 0x00 0x00 0x00 0x00 0x00 0x00 0x00 0x00 0x00 0x00 0x00 0x00 0x00 0x00
> > 0x00 0x00 0x00 0x00 0x00
> > FATAL: drivers/media/video/pvrusb2/pvrusb2: struct usb_device_id is not terminated
> > with a NULL entry!
> >
> > ("rusb2/pvrusb2" ??)
> 
> Hmm? Are you sure you didn't see any "drivers/media/video/pv" before the
> "rusb2/pvrusb2" bit?

Fairly.  I looked twice.

> Looking at Kees' patch (and the existing code), I've no
> clue how/why this should happen ... will try to reproduce here ...
> 
> 
> > but:
> >
> > struct usb_device_id pvr2_device_table[] = {
> >         [PVR2_HDW_TYPE_29XXX] = { USB_DEVICE(0x2040, 0x2900) },
> >         [PVR2_HDW_TYPE_24XXX] = { USB_DEVICE(0x2040, 0x2400) },
> >         { USB_DEVICE(0, 0) },
> > };
> >
> > looks OK?
> >
> > Using plain old "{ }" shut the warning up.
> 
> USB_DEVICE(0, 0) is not empty termination, actually, and this looks like
> a genuine bug caught by the patch. As that dump shows, USB_DEVICE(0, 0)
> assigns "0x03 0x00" (in little endian) to usb_device_id.match_flags. And
> I don't think the USB code treats such an entry as an empty entry (?)
> 
> Interestingly, the "USB_DEVICE(0, 0)" thing is absent from latest -git
> tree and also in my copy of 23-rc4-mm1 -- so this looks like something
> you must've merged recently.

git-dvb very carefully does

--- a/drivers/media/video/pvrusb2/pvrusb2-hdw.c~git-dvb
+++ a/drivers/media/video/pvrusb2/pvrusb2-hdw.c
@@ -44,7 +44,7 @@
 struct usb_device_id pvr2_device_table[] = {
 		[PVR2_HDW_TYPE_29XXX] = { USB_DEVICE(0x2040, 0x2900) },
 		[PVR2_HDW_TYPE_24XXX] = { USB_DEVICE(0x2040, 0x2400) },
-       { }
+       { USB_DEVICE(0, 0) },
};
	 
MODULE_DEVICE_TABLE(usb, pvr2_device_table);
	
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