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SubjectRe: [PATCH 0/5 v2] [GIT PULL] x86/jump label: Paranoid checks and 2 or 5 byte nops

* Steven Rostedt <rostedt@goodmis.org> wrote:

> On Tue, 2012-01-31 at 20:48 +0100, Ingo Molnar wrote:
>
> > Attached. (you need to run it through make oldconfig and use the
> > defaults.)
>
> Hmm, I'm not able to reproduce it.
>
> Could you apply this patch and run it again. I'm interested in what was
> at the location when it tried to do the conversion.
>
> Thanks!
>
> -- Steve
>
> diff --git a/arch/x86/kernel/jump_label.c b/arch/x86/kernel/jump_label.c
> index 6173ca6..da12264 100644
> --- a/arch/x86/kernel/jump_label.c
> +++ b/arch/x86/kernel/jump_label.c
> @@ -58,13 +58,17 @@ static void __jump_label_transform(struct jump_entry *entry,
> size = JUMP_LABEL_NOP_SIZE;
> code.jump = 0xe9;
> code.offset = entry->target - (entry->code + size);
> - } else
> + } else {
> + unsigned char *ins = ip;
> /*
> * The location is not a nop that we were expecting,
> * something went wrong. Crash the box, as something could be
> * corrupting the kernel.
> */
> + printk("Unknown op at %pS (%02x:%02x:%02x:%02x:%02x)\n",
> + ip, ins[0], ins[1], ins[2], ins[3], ins[4]);
> BUG();
> + }

It would be better to make this a regular commit, this kind of
diagnostics obviously makes sense. That way i could pull in your
updated branch for more testing.

Thanks,

Ingo


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