Red Hat Bugzilla – Bug 511185
kernel: build with -fno-delete-null-pointer-checks [rhel-3]
Last modified: 2009-11-03 17:00:26 EST
+++ 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.
Upstream 2.4 commit:
A patch for this issue has been included in build 2.4.21-61.EL.
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.