Red Hat Bugzilla – Bug 491264
kernel-rt should be built with -fwrapv [mrg-1]
Last modified: 2016-05-22 19:28:00 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
Not all versions of gcc support it, so we need to make it conditional (it looks like it was introduced in gcc-3.4).
Created attachment 335959 [details]
Verified by code review. Upstream patch (attached here) found in 18.104.22.168-117.el5rt source tree.
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,
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if the solution does not work for you.