Bug 14288 - BUG: bad unlock balance detected! trying to release lock (&futex_queues[i].lock)
Summary: BUG: bad unlock balance detected! trying to release lock (&futex_queues[i].lock)
Status: RESOLVED CODE_FIX
Alias: None
Product: Process Management
Classification: Unclassified
Component: Other (show other bugs)
Hardware: All Linux
: P1 normal
Assignee: process_other
URL:
Keywords:
Depends on:
Blocks:
 
Reported: 2009-10-01 06:18 UTC by Rich Ercolani
Modified: 2009-10-06 21:10 UTC (History)
2 users (show)

See Also:
Kernel Version: 2.6.31
Subsystem:
Regression: Yes
Bisected commit-id:

Attachments
Verbose output of bad unlock balance (40.48 KB, text/plain)
2009-10-01 06:18 UTC, Rich Ercolani 		Details
Add an attachment (proposed patch, testcase, etc.)

Description Rich Ercolani 2009-10-01 06:18:15 UTC 
Created attachment 23216 [details]
Verbose output of bad unlock balance

I awoke after upgrading to 2.6.31 one day to find a blank screen.

After attaching and configuring a serial console for the next time it occurred, I got [attachment 1 [details]].

Never occurred prior to 2.6.31.
Comment 1 Darren Hart 2009-10-04 14:21:43 UTC 
The bug was a result of the fault rework in e4dc5b7a36a49eff97050894cf1b3a9a02523717.  Thomas fixed it with 9694d494b7f462bffb86654fabe9e1ec2b2b0c47.  One of the retry_private optimization labels was placed after the double_lock_hb() instead of before it, leading to a double unlock on fault in wake_futex_op.
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