Re: [uml-devel] [PATCH] x86_64 32-bit ptrace mangles sixth system call argument

[Jeff D. <jd...@ad...>]

On Tue, Mar 06, 2007 at 12:03:26AM +0100, Blaisorblade wrote:
> > No, RCX corruption is different - that happens when a sysexit is done
> > from a system call where userspace wasn't prepared to save and restore
> > RCX.  sigreturn is the best example.
> 
> Hmm... we should finally fix that, at some point. Or... now that you explain 
> it this way, it could even seem unfixable... is it? Or maybe sysreturn should
> become a syscall where the return must happen through the slow return path 
> (iret), if that exists for x86_64.

This is fixed, and has been for a while.  The fix was, as you suggest, return
through iret in this case.

> > But, a 32-bit UML making mmap calls through sysenter indeed does not run
> > very well.
> 
> Has this been fixed? I've read that Chuck Ebbert had already fixed this in 
> your diary, but not sent the patch.

Yup, and I'm going to resurrect that patch.

> I'd open an entry in bugzilla for this sort of things. It also seems that 
> Jason Lunz's patch about max_low_pfn is not even in your tree

It is, I just haven't updated the site with it yet.

				Jeff

-- 
Work email - jdike at linux dot intel dot com