Hi,

The 2.6.20.x kernels all crash on my SMP-HT machine, and the oops report always shows that udev was trying to access an endpoint belonging to the snd-usb-audio driver. The frustrating part is that this particular endpoint shouldn't even exist! (It doesn't exist whenever I check the /sys/class/usb_endpoint directory.) Is there any way that userspace ("winecfg" in my case) can cause the snd-usb-audio driver to switch from (If# = 2, Alt = 0) to (If# = 2, Alt > 0) please? Because that is currently the only way that I can see this endpoint ever being created.

Thanks, Chris

--- bugme-daemon@bugzilla.kernel.org wrote:

Date: Sat, 14 Apr 2007 05:22:23 -0700 From: bugme-daemon@bugzilla.kernel.org To: rankincj@yahoo.com Subject: [Bug 8198] udevd triggers oops when walking through /sys

http://bugzilla.kernel.org/show_bug.cgi?id=8198

------- Additional Comments From rankincj@yahoo.com 2007-04-14 05:22 ------- Created an attachment (id=11144) --> (http://bugzilla.kernel.org/attachment.cgi?id=11144&action=view) dmesg output from 2.6.20.7 oops

I don't know if this output is any more useful than any of the others. And I can't see where the "single bit error" comes from when the output is full of "use after free" poison. However, this much at least is different:

EIP: [<6b6b6b6b>] 0x6b6b6b6b SS:ESP 0068:ec9eaf48 <3>Slab corruption: start=eceea92c, len=512 Redzone: 0x5a2cf071/0x5a2cf071. Last user: [<c0226642>](kfree_skbmem+0xb/0x9c) 080: 6b 6b 6b 6b 6a 6b 6b 6b 6b 6b 6b 6b 6b 6b 6b 6b Single bit error detected. Probably bad RAM. Run memtest86+ or a similar memory test tool. Prev obj: start=eceea720, len=512 Redzone: 0x170fc2a5/0x170fc2a5. Last user: [<f886eda5>](usb_create_ep_files+0xf1/0x2c2 [usbcore]) 000: f8 fd 1b c2 e0 ee 4e f7 01 00 00 00 00 00 00 00 010: 30 a7 ee ec 30 a7 ee ec f4 91 1e c0 96 90 1e c0 Next obj: start=eceeab38, len=512 Redzone: 0x5a2cf071/0x5a2cf071. Last user: [<c0226642>](kfree_skbmem+0xb/0x9c) 000: 6b 6b 6b 6b 6b 6b 6b 6b 6b 6b 6b 6b 6b 6b 6b 6b 010: 6b 6b 6b 6b 6b 6b 6b 6b 6b 6b 6b 6b 6b 6b 6b 6b

Again, it's claiming that the last sysfs file accessed was the non-existent /class/usb_endpoint/usbdev1.3_ep84/dev, which I simply cannot explain because this endpoint belongs to If# = 2, Alt > 0:

I: If#= 2 Alt= 0 #EPs= 0 Cls=01(audio) Sub=02 Prot=00 Driver=snd-usb-audio I: If#= 2 Alt= 1 #EPs= 1 Cls=01(audio) Sub=02 Prot=00 Driver=snd-usb-audio E: Ad=84(I) Atr=01(Isoc) MxPS= 90 Ivl=1ms I: If#= 2 Alt= 2 #EPs= 1 Cls=01(audio) Sub=02 Prot=00 Driver=snd-usb-audio E: Ad=84(I) Atr=01(Isoc) MxPS= 46 Ivl=1ms I: If#= 2 Alt= 3 #EPs= 1 Cls=01(audio) Sub=02 Prot=00 Driver=snd-usb-audio E: Ad=84(I) Atr=01(Isoc) MxPS= 25 Ivl=1ms I: If#= 2 Alt= 4 #EPs= 1 Cls=01(audio) Sub=02 Prot=00 Driver=snd-usb-audio E: Ad=84(I) Atr=01(Isoc) MxPS= 16 Ivl=1ms

Could the ALSA USB audio driver be changing the "Alt" on the fly somehow, causing usbcore to need to create the extra endpoint in /sys?

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