Bug 722565

Summary:	using page_count(pfn_to_page(pfn)) on a random pfn is unsafe
Product:	Red Hat Enterprise Linux 6	Reporter:	Andrea Arcangeli <aarcange>
Component:	kernel	Assignee:	Andrea Arcangeli <aarcange>
Status:	CLOSED ERRATA	QA Contact:	Caspar Zhang <czhang>
Severity:	low	Docs Contact:
Priority:	medium
Version:	6.2	CC:	czhang, qcai, tburke
Target Milestone:	rc
Target Release:	---
Hardware:	Unspecified
OS:	Unspecified
Whiteboard:
Fixed In Version:	kernel-2.6.32-171.el6	Doc Type:	Bug Fix
Doc Text:		Story Points:	---
Clone Of:		Environment:
Last Closed:	2011-12-06 13:52:15 UTC	Type:	---
Regression:	---	Mount Type:	---
Documentation:	---	CRM:
Verified Versions:		Category:	---
oVirt Team:	---	RHEL 7.3 requirements from Atomic Host:
Cloudforms Team:	---	Target Upstream Version:

Description Andrea Arcangeli 2011-07-15 16:38:05 UTC

Description of problem: using page_count(pfn_to_page(pfn)) on a random pfn is unsafe

Version-Release number of selected component (if applicable): 6.0 6.1 6.2


How reproducible: not easily reproduced, the only report is here http://marc.info/?l=linux-mm&m=131069449929254&w=2


Steps to Reproduce:
1. heavy vm activity with significant split_huge_page load
2.
3.
  
Actual results: bad pointer dereference


Expected results: no crash


Additional info:

Comment 2 Andrea Arcangeli 2011-07-15 17:08:35 UTC

Fixes posted on rhkernel-list with Message-ID: <20110715170151.GB31225> and Message-ID: <20110715170721.GC31225>.

Comment 4 RHEL Program Management 2011-07-17 13:19:54 UTC

This request was evaluated by Red Hat Product Management for inclusion
in a Red Hat Enterprise Linux maintenance release. Product Management has 
requested further review of this request by Red Hat Engineering, for potential
inclusion in a Red Hat Enterprise Linux Update release for currently deployed 
products. This request is not yet committed for inclusion in an Update release.

Comment 6 Kyle McMartin 2011-07-25 13:07:13 UTC

Patch(es) available on kernel-2.6.32-171.el6

Comment 12 errata-xmlrpc 2011-12-06 13:52:15 UTC

Since the problem described in this bug report should be
resolved in a recent advisory, it has been closed with a
resolution of ERRATA.

For information on the advisory, and where to find the updated
files, follow the link below.

If the solution does not work for you, open a new bug report.

http://rhn.redhat.com/errata/RHSA-2011-1530.html