Bug 12375

Summary:	ext4_block_to_path block too big cause cpu to burn
Product:	File System	Reporter:	David Maciejak (dmaciejak)
Component:	ext4	Assignee:	Theodore Tso (tytso)
Status:	CLOSED CODE_FIX
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

Regards,

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.