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

From: Miles Lane
Date: Sun Jul 02 2006 - 13:06:05 EST


On 7/2/06, Arjan van de Ven <arjan@xxxxxxxxxxxxx> wrote:

> https://wiki.ubuntu.com/GccSsp
>
> It appears that Ubuntu's Edgy Eft (the development tree) now contains
> "Stack Smashing Protection" enabled by default. I found a web page
> that states that -fno-stack-protector can be used to disable this
> functionality. Interestingly, another web page stated that SSP has
> been enabled in Redhat compilers for a long time and is now also
> enabled in Debian SID. Perhaps -fno-stack-protector should be added
> to the kernel build be default?


gcc 4.1 and later have this feature yes.
HOWEVER the gcc people were not stupid, they did not force this on
people, they require you to put -fstack-protector on the commandline.
Debian and RH/Fedora do this.
If Ubuntu patched gcc rather than just putting it in the build
environment... then you should switch to a less braindead distribution
really ;)
or at least ask them to fix this.

Well, from the web page referenced at the top of this message, you
can see that they are already aware of these issues:

Cons:
* It breaks current upstream kernel builds and potentially
other direct usages of gcc. Kernel is by far the most important use
case. Upstream should change the default options to build with
-fno-stack-protector by default.
* It is not conformant to upstream gcc behaviour.

You can reach the key people who are working on this for Ubuntu here:
Matt Zimmerman -- mdz at ubuntu dot com
Martin Pitt -- martin.pitt at ubuntu dot com

Perhaps you can convince them to back out this functional change?

Does this mean that you don't want to see these fno-stack-protector
patches go into Andrew's tree?

Miles
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