Bug 135171

Summary: Access to /proc/bus/usb/devices hangs the kernel
Product: [Fedora] Fedora Reporter: Alan Cox <alan>
Component: kernelAssignee: Pete Zaitcev <zaitcev>
Status: CLOSED RAWHIDE QA Contact: Brian Brock <bbrock>
Severity: high Docs Contact:
Priority: medium    
Version: 3CC: piskozub, wtogami
Target Milestone: ---   
Target Release: ---   
Hardware: All   
OS: Linux   
Fixed In Version: Doc Type: Bug Fix
Doc Text:
Story Points: ---
Clone Of: Environment:
Last Closed: 2004-10-16 17:45:16 EDT Type: ---
Regression: --- Mount Type: ---
Documentation: --- CRM:
Verified Versions: Category: ---
oVirt Team: --- RHEL 7.3 requirements from Atomic Host:
Cloudforms Team: ---
Bug Depends On:    
Bug Blocks: 123268, 130887    

Description Alan Cox 2004-10-09 14:13:13 EDT
Description of problem:

At any point after a USB timeout occurs (as they tend to do plugging
devices) the 
USB devices file access hang the system deadlocked on a semaphore.
This has horrible consequences

One test setup shows this during boot up so Anaconda hangs and you
cannot install.
A second shows it when the monitor (with USB hub) powers down. After
that anything touching the USB devices file hangs the box. 

Thirdly you can cause it to order as a user by inserting and quickly
removing a device, killing the hal layer and rendering the box
unusable without even having login access to it.

This bug appears to have arrived between 2.6.6 and 2.6.7 somewhere.
Comment 1 Alan Cox 2004-10-09 14:15:16 EDT
This also btw seems to cause some of the kudzu hangs people see.
Comment 2 Bill Nottingham 2004-10-11 10:43:44 EDT
Can you reproduce with .603, or even BK head?
Comment 3 Alan Cox 2004-10-11 10:49:57 EDT
Its present in current 2.6.9-rc snapshots too. Came in between 2.6.6
and 2.6.7 somewhere.
Comment 4 Alan Cox 2004-10-15 11:26:11 EDT
Done some more digging

I cannot reproduce this with vanilla, only various RH builds
so it looks like something that is specific to our tree. WIll test
.603 for completeness
Comment 5 Alan Cox 2004-10-15 12:01:50 EDT
*** Bug 134026 has been marked as a duplicate of this bug. ***
Comment 6 Alan Cox 2004-10-15 12:04:37 EDT
Propogating block from dup
Comment 7 Alan Cox 2004-10-16 17:45:16 EDT
541 has the buggy change -  624 is ok