Re: 2.6.17-mm5 -- Busted toolchain? -- usr/klibc/exec_l.c:59: undefined reference to `__stack_chk_fail'

H. Peter Anvin
2006-07-01T23:27:20Z

H. Peter Anvin wrote:
> Sam Ravnborg wrote:
>>
>> For klibc you need to patch scripts/Kbuild.klibc
>>
>> Appending it to KLIBCWARNFLAGS seems the right place.
>
> KLIBCREQFLAGS, rather.
>
>> Do you know from what gcc version we can start using
>> -fno-stack-protector?
>
> Isn't there a macro to test if gcc supports a specific option already?
>
> Either way, I can also add __stack_chk_fail() as an alias for abort(),
> for people who actually want the feature.
>

I looked at it again, and it looks like gcc depends on the TLS ABI in
order to pick the value of the cookie. That makes it a potentially lot
more cantankerous option; I would like to be able to support stack-smash
checking in klibc, but if it means implementing TLS on all
architectures, then that would really defeat the purpose (and we should
add -fno-stack-protector to KLIBCREQFLAGS.)

Arjan: I see a few stack-protector-related have your name on it, do you
have any details on implementation constraints for this across
architectures?

-hpa