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

[Satyam Sharma]

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? 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.
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