Bug 12375

Summary: ext4_block_to_path block too big cause cpu to burn
Product: File System Reporter: David Maciejak (dmaciejak)
Component: ext4Assignee: Theodore Tso (tytso)
Severity: normal    
Priority: P1    
Hardware: All   
OS: Linux   
Kernel Version: 2.6.28 Subsystem:
Regression: --- Bisected commit-id:
Attachments: kernel log extract
ext4 image poc
Patch to address this bug

Description David Maciejak 2009-01-07 02:56:33 UTC
Latest working kernel version: none
Earliest failing kernel version: unknow
Distribution: ubuntu
Hardware Environment: dell optiplex 740
Software Environment:
Problem Description:
when mounting specially crafted ext4 image, after some few seconds (5s), kern.log is filled with some data and cpu reaches 100%
Steps to reproduce:
bunzip the image file enclosed and mount the image with  mount -t ext4 -o loop ext4.img /media/tmp

note: i also tried the 2.6.28-ext4-3 patch but it does not help


David Maciejak
Fortinet's FortiGuard Global Security Research Team
Comment 1 David Maciejak 2009-01-07 02:57:13 UTC
Created attachment 19685 [details]
kernel log extract
Comment 2 David Maciejak 2009-01-07 02:57:41 UTC
Created attachment 19686 [details]
ext4 image poc
Comment 3 Theodore Tso 2009-01-17 15:44:48 UTC
Created attachment 19872 [details]
Patch to address this bug

This patch should address this bug.  Thanks for reporting it!
Comment 4 Theodore Tso 2009-02-03 11:20:31 UTC
This patch has been merged into the Linux mainline and will be 2.6.29-rc4 and newer releases.