Bug 710338 (CVE-2011-2183)

Summary: CVE-2011-2183 kernel: ksm: race between ksmd and exiting task
Product: [Other] Security Response Reporter: Eugene Teo (Security Response) <eteo>
Component: vulnerabilityAssignee: Red Hat Product Security <security-response-team>
Status: CLOSED ERRATA QA Contact:
Severity: medium Docs Contact:
Priority: medium    
Version: unspecifiedCC: arozansk, fhrbata, kernel-mgr, kmcmartin, lwang, nobody, pmatouse, qcui, sforsber, tcallawa
Target Milestone: ---Keywords: Security
Target Release: ---   
Hardware: All   
OS: Linux   
Fixed In Version: Doc Type: Bug Fix
Doc Text:
Story Points: ---
Clone Of: Environment:
Last Closed: 2015-07-29 12:48:43 UTC Type: ---
Regression: --- Mount Type: ---
Documentation: --- CRM:
Verified Versions: Category: ---
oVirt Team: --- RHEL 7.3 requirements from Atomic Host:
Cloudforms Team: --- Target Upstream Version:
Bug Depends On: 710340, 710341, 710988    
Bug Blocks:    

Description Eugene Teo (Security Response) 2011-06-03 05:55:23 UTC
Andrea Righi reported a case where an exiting task can race against ksmd.  

ksm_scan.mm_slot == the only registered mm
CPU 1 (bug program)		CPU 2 (ksmd)
 				list_empty() is false
 				slot == &ksm_mm_head (but list is now empty_)

Close this race by revalidating that the new slot is not simply the list head again.

Reproducer: http://www.spinics.net/lists/linux-mm/msg20233.html
Proposed patch: http://www.spinics.net/lists/linux-mm/msg20301.html


Red Hat would like to thank Andrea Righi for reporting this issue.

Comment 2 Eugene Teo (Security Response) 2011-06-03 06:03:50 UTC

This issue did not affect the versions of the Linux kernel as shipped with Red Hat Enterprise Linux 4, 5, and Red Hat Enterprise MRG do not provide support for KSM (Kernel Samepage Merging). This has been addressed in Red Hat Enterprise Linux 6 via https://rhn.redhat.com/errata/RHSA-2011-1189.html.

Comment 4 Chuck Ebbert 2011-06-23 09:24:46 UTC
Upstream commit:


Comment 5 Eugene Teo (Security Response) 2011-07-06 08:41:00 UTC
*** Bug 719238 has been marked as a duplicate of this bug. ***

Comment 6 errata-xmlrpc 2011-08-23 14:42:24 UTC
This issue has been addressed in following products:

  Red Hat Enterprise Linux 6

Via RHSA-2011:1189 https://rhn.redhat.com/errata/RHSA-2011-1189.html

Comment 7 errata-xmlrpc 2011-09-12 19:45:36 UTC
This issue has been addressed in following products:

  MRG for RHEL-6 v.2

Via RHSA-2011:1253 https://rhn.redhat.com/errata/RHSA-2011-1253.html