Re: [PATCH] objtool: fix rare switch jump table pattern detection

From: Arnd Bergmann
Date: Wed Oct 26 2016 - 12:04:27 EST


On Wednesday, October 26, 2016 10:34:08 AM CEST Josh Poimboeuf wrote:
> The following commit:
>
> 3732710ff6f2 ("objtool: Improve rare switch jump table pattern detection")
>
> ... improved objtool's ability to detect gcc switch statement jump
> tables for gcc 6. However the check to allow short jumps with the
> scanned range of instructions wasn't quite right. The pattern detection
> should allow jumps to the indirect jump instruction itself.
>
> This fixes the following warning:
>
> drivers/infiniband/sw/rxe/rxe_comp.o: warning: objtool: rxe_completer()+0x315: sibling call from callable instruction with changed frame pointer
>
> Reported-by: Arnd Bergmann <arnd@xxxxxxxx>
> Fixes: 3732710ff6f2 ("objtool: Improve rare switch jump table pattern detection")
> Signed-off-by: Josh Poimboeuf <jpoimboe@xxxxxxxxxx>

Tested-by: Arnd Bergmann <arnd@xxxxxxxx>

It fixes the mlx4/resource_tracker.o problem, but not the other
one for ttusb-dec/ttusb_dec.o, as you mentioned.

Do you need any more help creating a testcase for that one?

Arnd