Bug 491264

Summary: kernel-rt should be built with -fwrapv [mrg-1]
Product: Red Hat Enterprise MRG Reporter: Eugene Teo (Security Response) <eteo>
Component: realtime-kernelAssignee: Red Hat Real Time Maintenance <rt-maint>
Status: CLOSED ERRATA QA Contact: David Sommerseth <davids>
Severity: high Docs Contact:
Priority: high    
Version: 1.1CC: bhu, lgoncalv, ovasik, security-response-team, williams
Target Milestone: 1.1.3   
Target Release: ---   
Hardware: All   
OS: Linux   
Whiteboard:
Fixed In Version: Doc Type: Bug Fix
Doc Text:
Story Points: ---
Clone Of: Environment:
Last Closed: 2009-06-03 11:37:11 EDT Type: ---
Regression: --- Mount Type: ---
Documentation: --- CRM:
Verified Versions: Category: ---
oVirt Team: --- RHEL 7.3 requirements from Atomic Host:
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Description Flags
Upstream patch none

Description Eugene Teo (Security Response) 2009-03-20 02:25:28 EDT
Description of problem:
Add '-fwrapv' to gcc CFLAGS. This makes sure that gcc doesn't try to optimize away wrapping arithmetic, which the kernel occasionally uses for overflow testing, ie things like

if (ptr + offset < ptr)

which technically is undefined for non-unsigned types. See

http://bugzilla.kernel.org/show_bug.cgi?id=12597

for details.

Not all versions of gcc support it, so we need to make it conditional (it looks like it was introduced in gcc-3.4).
Comment 5 David Sommerseth 2009-05-26 10:32:03 EDT
Verified by code review.  Upstream patch (attached here) found in 2.6.24.7-117.el5rt source tree.
Comment 7 errata-xmlrpc 2009-06-03 11:37:11 EDT
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-2009-1081.html