Messages in this thread | | | Date | Wed, 30 Jul 2014 09:27:47 +0200 | From | Markus Trippelsdorf <> | Subject | Re: [PATCH 3.15 33/37] Fix gcc-4.9.0 miscompilation of load_balance() in scheduler |
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On 2014.07.30 at 09:21 +0200, Jakub Jelinek wrote: > On Wed, Jul 30, 2014 at 09:13:08AM +0200, Markus Trippelsdorf wrote: > > On 2014.07.30 at 08:53 +0200, Jakub Jelinek wrote: > > > On Tue, Jul 29, 2014 at 06:49:09PM -0700, Greg Kroah-Hartman wrote: > > > > 3.15-stable review patch. If anyone has any objections, please let me know. > > > > > > IMNSHO this is a too big hammer approach. The bug happened on a single > > > file only (right?), so if anything, IMHO it could be disabled for that > > > single file only, and better do it only for compilers with the bug. > > > > No. There are many more files affected. It just happens that Linus > > analyzed the assembly of this single file (fair.c) and found a bug. > > Just build your redhat distro kernel with GCC_COMPARE_DEBUG=1 and you'll > > see. So unless someone analyzes the assembly output of all other > > affected files by hand and finds no issues, one has to assume the worst. > > I'm talking about wrong-code issues. For -fcompare-debug, we indeed check > it primarily during gcc bootstrap (through bootstrap-debug) and some > testcases, and we'll certainly try to build some more code with > -fcompare-debug and fix the issues.
Yes, I'm talking about wrong-code issues, too. For example the pr61801.c testcase was reduced from kernel/exit.c.
-- Markus
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