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Bug 230978 - A timing window that causes double freeing file_lock entry
Summary: A timing window that causes double freeing file_lock entry
Status: CLOSED DUPLICATE of bug 230976
Alias: None
Product: Red Hat Enterprise Linux 4
Classification: Red Hat
Component: kernel
Version: 4.4
Hardware: All
OS: Linux
Target Milestone: ---
: ---
Assignee: Red Hat Kernel Manager
QA Contact: Brian Brock
Depends On:
TreeView+ depends on / blocked
Reported: 2007-03-05 09:18 UTC by Tadashi Iwashita
Modified: 2007-11-17 01:14 UTC (History)
0 users

Fixed In Version:
Doc Type: Bug Fix
Doc Text:
Clone Of:
Last Closed: 2007-03-09 16:37:31 UTC
Target Upstream Version:

Attachments (Terms of Use)
crash "log" command output at kernel panic (deleted)
2007-03-05 09:18 UTC, Tadashi Iwashita
no flags Details

Description Tadashi Iwashita 2007-03-05 09:18:08 UTC
Description of problem:
Encountered (1) a kernel panic and (2) a system hang on web server running 
with mod_jk when ApacheBench tool from another node started. 

(1) kernel panic
Panic at line 168 on fs/lock.c displaying "Attempting to free lock on active 
lock list" due to a bad fl_link. Please see the the output of crash "log" 
command (attached as kernel_panic.txt).
(2) system hang
Loop at line 737 on fs/lock.c with holding lock_kernel due to a self-linked 
fl_next. Please see the output of crash "log" command (attached as 

Version-Release number of selected component (if applicable):

How reproducible:

Steps to Reproduce:
Just run ApacheBench tool for SMP web server.
Additional info:
With some kinds of kernel trapper and by looking at the kernel dump, it is 
most likely that the problem was caused by double freeing file_lock entry at a 
timing window. Checked LKML, then found and 
the patch for this issue has already been applied to upper version.

ApacheBench worked normally with the patch (attached flock.patch), so please 
consider applying this patch to the next stability updates or as a security 
update. Thanks.

Comment 1 Tadashi Iwashita 2007-03-05 09:18:08 UTC
Created attachment 149252 [details]
crash "log" command output at kernel panic

Comment 2 Tadashi Iwashita 2007-03-06 08:40:58 UTC
Please cancel this entry because the same problem has been reported on 
ID=230976. I pushed "commit" button twice by mistake.

Comment 3 Linda Wang 2007-03-09 16:37:31 UTC

*** This bug has been marked as a duplicate of 230976 ***

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