Re: [PATCHSET x86/master] add stack protector support for x86_32

Tejun Heo
2009-02-10T14:27:11Z

Ingo Molnar wrote:
>>> 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?

It seems that even with the same gcc versions, gcc built against libc
w/o TLS support generates __stack_chk_guard, so if you mix the two
flavors, the has-stack-protector check can be compiled on machines w/
TLS while some other files end up being built on machines w/o TLS
support thus circumventing the support check. Can you please see
whether non-distcc build fails too?

Thanks.

--
tejun