Messages in this thread | | | Date | Tue, 10 Feb 2009 15:20:26 +0100 | From | Ingo Molnar <> | Subject | Re: [PATCHSET x86/master] add stack protector support for x86_32 |
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* Tejun Heo <tj@kernel.org> wrote:
> Tejun Heo wrote: > > Ingo Molnar wrote: > >> * Ingo Molnar <mingo@elte.hu> wrote: > >> > >>> [...] I might not get around testing it today and pushing it out into tip:master, > >>> but i pushed out the core/percpu bits, should you queue up further changes. > >> ok, activated it for -tip testing, and there's a 64-bit build failure caused by > >> it: > >> > >> arch/x86/kernel/head64.o: In function `x86_64_start_reservations': > >> head64.c:(.init.text+0x26): undefined reference to `__stack_chk_guard' > >> head64.c:(.init.text+0xc2): undefined reference to `__stack_chk_guard' > >> arch/x86/kernel/head64.o: In function `x86_64_start_kernel': > >> head64.c:(.init.text+0x104): undefined reference to `__stack_chk_guard' > >> head64.c:(.init.text+0x1cd): undefined reference to `__stack_chk_guard' > >> arch/x86/kernel/head.o: In function `reserve_ebda_region': > >> head.c:(.init.text+0xb): undefined reference to `__stack_chk_guard' > >> arch/x86/kernel/head.o:head.c:(.init.text+0x87): more undefined references to > >> `__stack_chk_guard' follow > > > > Call to __stack_chk_guard is probably generated automatically. > > Strangely, my gcc only generates calls to __stack_chk_fail. > > > > > gcc --version > > gcc (SUSE Linux) 4.3.2 [gcc-4_3-branch revision 141291] > > Copyright (C) 2008 Free Software Foundation, Inc. > > This is free software; see the source for copying conditions. There is NO > > warranty; not even for MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE. > > > nm build/vmlinux|grep __stack_chk_ > > 00000000f0fdf6cb A __crc___stack_chk_fail > > ffffffff80d53e50 r __kcrctab___stack_chk_fail > > ffffffff80d5ff81 r __kstrtab___stack_chk_fail > > ffffffff80d3d140 r __ksymtab___stack_chk_fail > > ffffffff80248619 T __stack_chk_fail > > > > I'll try other compilers but which version are you using? The > > difference is that before the patchset, -fno-stack-protector was > > always added whether stackprotector was enabled or not so this problem > > wasn't visible (at the cost of bogus stackprotector of course). We'll > > probably need to add __stack_chk_guard or disable if gcc generates > > such symbol. I'll play with different gccs. > > Can't reproduce with gcc-4.1 or 4.2. Any chance you're using distcc > w/ a build machine w/ glibc < 2.4? __stack_chk_guard is the symbol > gcc fetches stack canary from if TLS is not supported, so somehow gcc > thought that TLS wasn't available while building head64.
yeah - i also used distcc. Maybe the nostackp makefile magic gets confused about that?
Ingo
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