On Fri, Nov 06, 2015 at 12:30:09PM +0000, Will Deacon wrote:
On Wed, Nov 04, 2015 at 09:37:51AM -0800, Yang Shi wrote:
FRAME_POINTER is defined in lib/Kconfig.debug, it is unnecessary to redefine it in arch/arm64/Kconfig.debug.
It might be worth noting that this adds a dependency on DEBUG_KERNEL for building with frame pointers. I'm ok with that (it appears to be enabled in defconfig and follows the vast majority of other archs) but it is a change in behaviour.
With that:
Acked-by: Will Deacon will.deacon@arm.com
The code in arch/arm64/kernel/stacktrace.c assumes we have frame pointers regardless of FRAME_POINTER. Depending on what the compiler decides to use x29 for, we could get some weird fake unwinding and/or dodgy memory accesses.
I think we should first audit the uses of frame pointers to ensure that they are guarded for !FRAME_POINTER.
Thanks, Mark.