Re: [RESEND PATCH] ARM: Recover kretprobes return address for EABI stack unwinder

[Chen Zhongjin]

On 2022/8/22 19:20, Linus Walleij wrote:
> On Mon, Aug 15, 2022 at 1:06 PM Chen Zhongjin <chenzhongjin@xxxxxxxxxx> wrote:
>
> > 'fed240d9c974 ("ARM: Recover kretprobe modified return address in stacktrace")'
> > has implemented kretprobes return address recovery for FP
> > unwinder, this patch makes it works for EABI unwinder.
> >
> > It saves __kretprobe_trampoline address in LR on stack to identify
> > and recover the correct return address in EABI unwinder.
> >
> > Since EABI doesn't use r11 as frame pointer, we need to use SP to
> > identify different kretprobes addresses. Here the value of SP has fixed
> > distance to conventional FP position so it's fine to use it.
> >
> > Passed kunit kprobes_test on QEMU.
> >
> > Signed-off-by: Chen Zhongjin <chenzhongjin@xxxxxxxxxx>
> This looks correct to me FWIW I understand the assembly
> but I'm vaguely unfamiliar with the kprobe API, but anyway:
> Reviewed-by: Linus Walleij <linus.walleij@xxxxxxxxxx>
>
> Would you please drop it into Russell's patch tracker?

Done for it.

Thanks for review!


Best,

Chen

> Yours,
> Linus Walleij