Re: [PATCH 9/19] UML - Tidy ptrace interface

From: WANG Cong
Date: Tue Apr 29 2008 - 04:15:57 EST


On Mon, 28 Apr 2008, Jeff Dike wrote:

On Sat, Apr 26, 2008 at 05:35:38PM +0800, WANG Cong wrote:
From: Jeff Dike <jdike@xxxxxxxxxxx>
Date: Fri, 25 Apr 2008 13:56:10 -0400
> Tidy the ptrace interface code. Removed a bunch of unused macros.
> Started converting register sets from arrays of longs to structures.

Could you please explain a bit why do this? I think long arrary is OK.

It's wrong on x86_64. There, FRAME_SIZE is 168 -
#define FRAME_SIZE and SS is the last register defined -
#define SS 160
but there are a number of registers beyond that in the user_regs_struct:
unsigned long ss;
unsigned long fs_base;
unsigned long gs_base;
unsigned long ds;
unsigned long es;
unsigned long fs;
unsigned long gs;

The effect of GETREGS into a long[FRAME_SIZE] will be stack corruption.


Thanks for teaching this. ;-)

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