Bug 511185 - kernel: build with -fno-delete-null-pointer-checks [rhel-3]
kernel: build with -fno-delete-null-pointer-checks [rhel-3]
Product: Red Hat Enterprise Linux 3
Classification: Red Hat
Component: kernel (Show other bugs)
All Linux
urgent Severity high
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Assigned To: Don Howard
Martin Jenner
Depends On: 511181
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Reported: 2009-07-14 00:37 EDT by Eugene Teo (Security Response)
Modified: 2009-11-03 17:00 EST (History)
2 users (show)

See Also:
Fixed In Version:
Doc Type: Bug Fix
Doc Text:
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Clone Of: 511181
Last Closed: 2009-11-03 17:00:26 EST
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RHEL 7.3 requirements from Atomic Host:
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Description Eugene Teo (Security Response) 2009-07-14 00:37:45 EDT
+++ This bug was initially created as a clone of Bug #511181 +++

Description of problem:

    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 2 Eugene Teo (Security Response) 2009-07-16 20:23:33 EDT
Upstream commit:
Comment 5 Don Howard 2009-10-16 14:50:02 EDT
A patch for this issue has been included in build 2.4.21-61.EL.
Comment 9 errata-xmlrpc 2009-11-03 17:00:26 EST
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.


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