Bug 710338 (CVE-2011-2183) - CVE-2011-2183 kernel: ksm: race between ksmd and exiting task
Summary: CVE-2011-2183 kernel: ksm: race between ksmd and exiting task
Alias: CVE-2011-2183
Product: Security Response
Classification: Other
Component: vulnerability
Version: unspecified
Hardware: All
OS: Linux
Target Milestone: ---
Assignee: Red Hat Product Security
QA Contact:
: 719238 (view as bug list)
Depends On: 710340 710341 710988
TreeView+ depends on / blocked
Reported: 2011-06-03 05:55 UTC by Eugene Teo (Security Response)
Modified: 2021-02-24 15:20 UTC (History)
10 users (show)

Fixed In Version:
Doc Type: Bug Fix
Doc Text:
Clone Of:
Last Closed: 2015-07-29 12:48:43 UTC

Attachments (Terms of Use)

System ID Private Priority Status Summary Last Updated
Red Hat Product Errata RHSA-2011:1189 0 normal SHIPPED_LIVE Important: kernel security, bug fix, and enhancement update 2011-08-23 14:41:43 UTC
Red Hat Product Errata RHSA-2011:1253 0 normal SHIPPED_LIVE Important: kernel-rt security and bug fix update 2011-09-12 19:43:48 UTC

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

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