Bug 769711 (CVE-2011-4621)

Summary:	CVE-2011-4621 kernel: tight loop and no preemption can cause system stall
Product:	[Other] Security Response	Reporter:	Petr Matousek <pmatouse>
Component:	vulnerability	Assignee:	Red Hat Product Security <security-response-team>
Status:	CLOSED ERRATA	QA Contact:
Severity:	medium	Docs Contact:
Priority:	medium
Version:	unspecified	CC:	anton, arozansk, dhoward, fhrbata, kernel-mgr, lwang, sforsber
Target Milestone:	---	Keywords:	Security
Target Release:	---
Hardware:	All
OS:	Linux
Whiteboard:
Fixed In Version:		Doc Type:	Bug Fix
Doc Text:		Story Points:	---
Clone Of:		Environment:
Last Closed:	2013-08-24 12:48:31 UTC	Type:	---
Regression:	---	Mount Type:	---
Documentation:	---	CRM:
Verified Versions:		Category:	---
oVirt Team:	---	RHEL 7.3 requirements from Atomic Host:
Cloudforms Team:	---	Target Upstream Version:
Embargoed:
Bug Depends On:	749785, 769715, 812183
Bug Blocks:	767920

Description Petr Matousek 2011-12-21 20:29:32 UTC

A tight loop in user level process isn't preempted unless a realtime process is woken up on the cpu.  Some important kernel threads such as events/*, kblockd/* can be blocked by the process, and the machine stalls.

Unprivileged local user could use this flaw to DoS the system.

Upstream commit:
http://git.kernel.org/linus/f26f9aff6aaf67e9a430d16c266f91b13a5bff64

Reference:
https://lkml.org/lkml/2010/11/20/212

Acknowledgements:

Red Hat would like to thank Masaki Tachibana for reporting this issue.

Comment 2 Kurt Seifried 2011-12-21 22:23:00 UTC

Added CVE-2011-4621 as per http://www.openwall.com/lists/oss-security/2011/12/21/6

Comment 3 Eugene Teo (Security Response) 2012-04-13 01:40:31 UTC

Created kernel tracking bugs for this issue

Affects: fedora-all [bug 812183]

Comment 6 Petr Matousek 2013-08-24 12:48:31 UTC

Statement:

This issue does not affect Red Hat Enterprise Linux 5 and Red Hat Enterprise MRG 2.