Messages in this thread | | | Date | Fri, 6 Nov 2015 12:50:02 +0000 | From | Mark Rutland <> | Subject | Re: [PATCH] arm64: remove redundant FRAME_POINTER kconfig option |
| |
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.
| |