Hi there.. There seems to be another problem with gcc 4.7.1.. We had some serious issues with programs crashing predictable on one machine and never on others with identical software/kernel.
It turned out that programs compiled with gcc 4.7.1 that are run on a processor with FMA4 extension segfault, if they entered fma4-optimized sections of the glibc. After recompiling glibc (same version) with 4.7.2 everything was fine.. so I actually never had a second look at what the problem really was nor did I do any more research in any bug databases. So I am not sure where this bug was fixed and what the actual problem was. But it actually broke emacs and some bio-software on cpus with the FMA4 extension. (After debugging and disassembling the error was not really in the FMA4 instruction itself but in the code gcc created after calling the fma4 instructions..) gcc 4.7.1 seems to be fishy 8) Best, marius.. On 08/23/12 03:34, Ken Moffat wrote: > Just a heads-up that on at least one box (mine), gcc-4.7.1 might be > problematic for the kernel in certain circumstances. > > I've been using 3.5.0 on the LFS-7.1 system on this box, and it is > fine. Didn't have time to upgrade the kernel, but 3.5.2 came out > during my latest build - so, I dropped that in. > > Thought I had a kernel problem - when I use my KVM switch to change > to my other desktop box, _and_ that box is running X, I lose a tall > chunk in the bottom left of the screen. Now that I've got X in use > on this machine, I can see that the bottom right is in fact repeated > at the bottom left - on a 133x54 text screen, that part at the right > is usually empty, so it looks as if someone put a card over the > corner of the screen. > > Tonight, I've started building other kernels to try to see if it has > already been fixed. Both 3.5.3-rc1 and 3.6-rc3 also show the > problem. And then I tried switching the KVM while using 3.5.0 - the > problem is there too. :-( > > So, not a kernel regression, if I'm reading my results correctly > it's a gcc problem (4.6.2 on the LFS-7.1 installation, 4.7.1 now - > both with binutils-2.22). Serves me right for breaking my rule to > *always* try the same version of the kernel on the (LFS) host > system, I suppose. > > With luck, it's not going to affect many people - we'll find out > during the -rc testing. > > ĸen > -- Dipl.-Inf. Marius Tolzmann <marius.tolzm...@molgen.mpg.de> ----------------------------------.------------------------------ MPI f. molekulare Genetik | Ihnestrasse 63-73, D-14195 Berlin | ==> MarIuX GNU/Linux <== Phone: +49 (0)30 8413 1709 | ----------------------------------^------------------------------ God put me on earth to accomplish a certain number of things. Right now I am so far behind.. ..I will never die. <by calvin from calvin&hobbes ;)>
smime.p7s
Description: S/MIME Cryptographic Signature
-- http://linuxfromscratch.org/mailman/listinfo/lfs-dev FAQ: http://www.linuxfromscratch.org/faq/ Unsubscribe: See the above information page
