Re: [PATCH v3] arm: fix a wrong value returned from CALLER_ADDRn

From: Russell King - ARM Linux
Date: Fri Mar 15 2013 - 13:35:23 EST


On Thu, Mar 14, 2013 at 01:35:01PM +0900, kpark3469@xxxxxxxxx wrote:
> From: Sahara <keun-o.park@xxxxxxxxxxxxx>
>
> This makes return_address() return a correct value for CALLER_ADDRn.
> To have a correct value from CALLER_ADDRn, we need to fix three points.
>
> * The unwind_frame() does not update frame->lr but frame->pc for backtrace.
> So frame->pc is meaningful for backtrace.
>
> * data.level should be adjusted by adding 2 additional iteration levels.
> With the current +1 level adjustment, the result of CALLER_ADDR1 will
> be the same return address with CALLER_ADDR0.
>
> * The initialization of data.addr to NULL is needed.
> When unwind_fame() fails right after data.level reaches zero,
> the routine returns data.addr which has uninitialized garbage value.
>
> Signed-off-by: Sahara <keun-o.park@xxxxxxxxxxxxx>
> Reviewed-by: Dave Martin <dave.martin@xxxxxxxxxx>

Please send this to the patch system. I think we should let this sit
in -next for a bit (which we'll get anyway) to see what the effect is.
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