Re: [patch 81/85] x86: fix RIP printout in early_idt_handler

[Greg KH]

On Fri, Jan 16, 2009 at 11:27:57AM +0800, Jike Song wrote:
> On Fri, Jan 16, 2009 at 6:02 AM, Greg KH <gregkh@xxxxxxx> wrote:
> > 2.6.27-stable review patch.  If anyone has any objections, please let us know.
> >
> > ------------------
> >
> > From: Jiri Slaby <jirislaby@xxxxxxxxx>
> >
> > commit 7aed55d1085f71241284a30af0300feea48c36db upstream.
> >
> > Impact: fix debug/crash printout
> >
> > Since errorcode is popped out, RIP is on the top of the stack.
> > Use real RIP value instead of wrong CS.
> >
> > Signed-off-by: Jiri Slaby <jirislaby@xxxxxxxxx>
> > Signed-off-by: Ingo Molnar <mingo@xxxxxxx>
> > Signed-off-by: Greg Kroah-Hartman <gregkh@xxxxxxx>
> >
> > ---
> >  arch/x86/kernel/head_64.S |    2 +-
> >  1 file changed, 1 insertion(+), 1 deletion(-)
> >
> > --- a/arch/x86/kernel/head_64.S
> > +++ b/arch/x86/kernel/head_64.S
> > @@ -305,7 +305,7 @@ ENTRY(early_idt_handler)
> >        call dump_stack
> >  #ifdef CONFIG_KALLSYMS
> >        leaq early_idt_ripmsg(%rip),%rdi
> > -       movq 8(%rsp),%rsi       # get rip again
> > +       movq 0(%rsp),%rsi       # get rip again
> >        call __print_symbol
> >  #endif
> >  #endif /* EARLY_PRINTK */
> 
> why not:
> 
>     movq (%rsp), %rsi
> 
> instead? Yes, it's all the same but 0 is just unnecessary.

I supposed in light of the previous verison having "8" it's to be a bit
more explicit :)

thanks,

greg k-h
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