Re: [crash, bisected] Re: [PATCH 3/4] x86_64: Fold pda into per cpu area

["H. Peter Anvin" <hpa@zytor.com>]

Mike Travis wrote:
> 
> One interesting thing I've discovered is the gcc --version may make a
> difference.
> 
> The kernel panic that occurred from Ingo's config, I was able to replicate
> with GCC 4.2.0 (which is on our devel server).  But this one complained
> about not being able to handle the STACK-PROTECTOR option so I moved
> everything to another machine that has 4.2.4, and now it seems that it
> works fine.  I'm still re-verifying that the source bits and config options 
> are identical (it was a later git-remote update), and that in fact it is
> the gcc --version, but that may be the conclusion.  (My code also has some
> patches submitted but not yet included in the tip/master tree.  Curiously
> just enabling some debug options changed the footprint of the panic.)
> 
> Are we allowed to insist on a specific level of GCC for compiling the
> kernel?
> 

Yes, but certainly not anything even close to that recent -- I think 
right now we're supposed to support back to 3.2-something overall; 
specific architectures might have more stringent requirements.  There 
are a couple of gcc versions known to miscompile there kernel that we 
don't support; I don't know if 4.2.0 is one of them.

	-hpa