Subject: Re: issues w/init

From: Benjamin Herrenschmidt <[email-masked]>
Date: Fri, 17 Apr 2009 12:41:00 +0200

On Fri, 2009-04-17 at 20:05 +1000, Paul Mackerras wrote:
> Benjamin Herrenschmidt writes:
> 
> > I'm pretty sure they are broken already when running off a 64-bit
> > kernel,
> 
> Maybe not... for 64-bit kernels we have our definition of
> elf_read_implies_exec in arch/powerpc/include/asm/elf.h, which IIRC
> sets the read-implies-exec personality thing on old 32-bit binaries.

Ok, so looking at that more closely, if that had worked, we would
have had PROT_EXEC, and thus VM_EXEC added to the vma by mmap... which
apparently didn't occur.

I think what may be happening is that the binary he's running has the
PT_GNU_STACK but his libc doesn't ... the kernel will set the
personality flag based on the binary you are trying to run, not any
library it uses...

Kumar, can you try to instrument that a bit and tell us ? What the
personality flag gets set to and whether mmap sets PROT_EXEC ?

Cheers,
Ben.