Re: [linux-usb-devel] Re: serious 2.6 bug in USB subsystem?

From: David Brownell
Date: Sun Nov 02 2003 - 22:56:22 EST



David> I'm not sure that if the HID driver were to pass a null
David> buffer pointer, it would be caught anywhere.

OK, I'll try to find some time to trace the I/O MMU calls to see if
something isn't kosher at that level. Is there a good way of getting
a relatively high-level of tracing in the USB subsystem that would
some me what's going on between the HID and the core USB level?

Most of that story is just submitting and completing URBs.

I'd either try changing the spots in drivers/usb/core/hcd.c
marked as appropriate for generic MONITOR_URB hooks (printk
if it's your HID device, maybe), or manually turn on whatever
HCD-specific hooks exist (maybe use a VERBOSE message level).

Such a thing wasn't possible in 2.4 since there were too
many different bizarre (and sometimes buggy) ways for URBs
to return to the usb device drivers and get implicitly
resubmitted.

- Dave




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