Re: Serial related oops

[Frederik Deweerdt]

On Wed, Feb 21, 2007 at 09:57:50PM -0800, H. Peter Anvin wrote:
> Russell King wrote:
> 
> >Plainly, %ebx changed across the call to serial_in() at c01c0f7b.
> >First thing to notice is this violates the C code - "up" can not
> >change.
> >Now let's look at serial_in:
> >c01bfa70:       55                      push   %ebp
> >c01bfa71:       89 e5                   mov    %esp,%ebp
> >c01bfa73:       53                      push   %ebx
> >...
> >c01bfab7:       5b                      pop    %ebx
> >c01bfab8:       5d                      pop    %ebp
> >c01bfab9:       c3                      ret
> >This code tells the CPU to preserves %ebx and %ebp.  But we know %ebx
> >_wasn't_ preserved.  Ergo, your CPU is plainly not doing what the code
> >told it to do.
> 
> ... assuming nothing else clobbered the stack slot (which would be a compiler 
> error, or a wild pointer.)
> 
> Got a disassembly of the whole function?
> 
Jose posted it higher in the thread:
http://lkml.org/lkml/2007/2/21/139

Regards,
Frederik
-
To unsubscribe from this list: send the line "unsubscribe linux-kernel" in
the body of a message to majordomo@xxxxxxxxxxxxxxx
More majordomo info at  http://vger.kernel.org/majordomo-info.html
Please read the FAQ at  http://www.tux.org/lkml/