Re: [PATCH 2/19] UML - Tidy stub management code

From: WANG Cong
Date: Tue Apr 29 2008 - 03:58:46 EST


On Mon, 28 Apr 2008, Jeff Dike wrote:

On Sat, Apr 26, 2008 at 06:01:12PM +0800, WANG Cong wrote:
> + /*
> + * When the stub stops, we find the following values on the
> + * beginning of the stack:
> + * (long) return_value
> + * (long) offset to failed sycall data (0 if no error)
> + */
> + ret = *((unsigned long *) stack);


I am afraid the value will be truncated on 64bit machine, since
'ret' is 'int' while 'stack' points to an 'unsigned long'.

Is this expected?

That's dubious, but I don't think it breaks anything. On LE, *(int *)
and *(long *) will give you the same answer, and the value here is an
error code, which fits into 32 bits.

So it's safe here.

OK. Thanks!

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