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Bug 511181

Summary:	kernel: build with -fno-delete-null-pointer-checks [rhel-5.4]
Product:	Red Hat Enterprise Linux 5	Reporter:	Eugene Teo (Security Response) <eteo>
Component:	kernel	Assignee:	Eugene Teo (Security Response) <eteo>
Status:	CLOSED ERRATA	QA Contact:	Red Hat Kernel QE team <kernel-qe>
Severity:	high	Docs Contact:
Priority:	urgent
Version:	5.4	CC:	cebbert, davej, dhoward, dzickus, emcnabb, eparis, jakub, jpirko, jplans, jskrabal, kyle, lwang, mgahagan
Target Milestone:	rc	Keywords:	ZStream
Target Release:	---
Hardware:	All
OS:	Linux
Whiteboard:
Fixed In Version:		Doc Type:	Bug Fix
Doc Text:		Story Points:	---
Clone Of:
Clones:	511183 511185 511187 (view as bug list)		Environment:
Last Closed:	2009-09-02 08:06:28 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:
Bug Blocks:	511183, 511185, 511187, 515468

Description Eugene Teo (Security Response) 2009-07-14 03:37:40 UTC

Description of problem:
http://gcc.gnu.org/onlinedocs/gcc-4.1.2/gcc/Optimize-Options.html

-fdelete-null-pointer-checks
    Use global dataflow analysis to identify and eliminate useless checks for null pointers. The compiler assumes that dereferencing a null pointer would have halted the program. If a pointer is checked after it has already been dereferenced, it cannot be null.

    In some environments, this assumption is not true, and programs can safely dereference null pointers. Use -fno-delete-null-pointer-checks to disable this optimization for programs which depend on that behavior.

    Enabled at levels -O2, -O3, -Os.

Comment 9 RHEL Program Management 2009-07-14 22:03:33 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 10 Eugene Teo (Security Response) 2009-07-17 00:20:08 UTC

Upstream commit:
http://git.kernel.org/linus/a3ca86aea507904148870946d599e07a340b39bf

Comment 13 Don Zickus 2009-07-21 19:37:29 UTC

in kernel-2.6.18-159.el5
You can download this test kernel from http://people.redhat.com/dzickus/el5

Please do NOT transition this bugzilla state to VERIFIED until our QE team
has sent specific instructions indicating when to do so.  However feel free
to provide a comment indicating that this fix has been verified.

Comment 19 errata-xmlrpc 2009-09-02 08:06:28 UTC

An advisory has been issued which should help the problem
described in this bug report. This report is therefore being
closed with a resolution of ERRATA. For more information
on therefore solution and/or where to find the updated files,
please follow the link below. You may reopen this bug report
if the solution does not work for you.

http://rhn.redhat.com/errata/RHSA-2009-1243.html