Re: I'll queue a patch for 3.11 which removes the #ifdef... (was: Re: idle: Add the stack canary init to cpu_startup_entry())

From: Thomas Gleixner
Date: Fri May 09 2014 - 16:26:37 EST


On Fri, 9 May 2014, Geert Uytterhoeven wrote:

> On Thu, Jun 20, 2013 at 8:31 PM, Linux Kernel Mailing List
> <linux-kernel@xxxxxxxxxxxxxxx> wrote:
> > Gitweb: http://git.kernel.org/linus/;a=commit;h=d7880812b3594d3c6dcbe3cfd71dabb17347d082
> > Commit: d7880812b3594d3c6dcbe3cfd71dabb17347d082
> > Parent: c7788792a5e7b0d5d7f96d0766b4cb6112d47d75
> > Author: Thomas Gleixner <tglx@xxxxxxxxxxxxx>
> > AuthorDate: Mon Jun 10 16:52:03 2013 +0200
> > Committer: Thomas Gleixner <tglx@xxxxxxxxxxxxx>
> > CommitDate: Tue Jun 11 22:04:47 2013 +0200
> >
> > idle: Add the stack canary init to cpu_startup_entry()
> >
> > Moving x86 to the generic idle implementation (commit 7d1a9417 "x86:
> > Use generic idle loop") wreckaged the stack protector.
> >
> > I stupidly missed that boot_init_stack_canary() must be inlined from a
> > function which never returns, but I put that call into
> > arch_cpu_idle_prepare() which of course returns.
> >
> > I pondered to play tricks with arch_cpu_idle_prepare() first, but then
> > I noticed, that the other archs which have implemented the
> > stackprotector (ARM and SH) do not initialize the canary for the
> > non-boot cpus.
> >
> > So I decided to move the boot_init_stack_canary() call into
> > cpu_startup_entry() ifdeffed with an CONFIG_X86 for now. This #ifdef
> > is just a temporary measure as I don't want to inflict the
> > boot_init_stack_canary() call on ARM and SH that late in the cycle.
> >
> > I'll queue a patch for 3.11 which removes the #ifdef if the ARM/SH
> > maintainers have no objection.
>
> Any progress here?

Obviosly not. None of the !x86 folks seemed to think that it matters
and I simply forgot about it. Bah, I can't even find the complex patch
anymore which solves that issue.

The main complexity is:

-#ifdef CONFIG_X86
...
-#ifdef

But I didn't want to do that without input of the affected subarch
maintainers.

Care to send that patch and I'll throw it into next and we watch the
resulting fireworks together :)

Thanks,

tglx
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