Re: [RFC][PATCH 5/7] jump_label: Rework update logic

From: Peter Zijlstra
Date: Mon Jul 27 2015 - 05:08:08 EST


On Fri, Jul 24, 2015 at 07:52:14PM +0200, Peter Zijlstra wrote:
> @@ -330,8 +318,7 @@ static int jump_label_add_module(struct
> jlm->next = key->next;
> key->next = jlm;
>
> - if (jump_label_type(key) == JUMP_LABEL_JMP)
> - __jump_label_update(key, iter, iter_stop, JUMP_LABEL_JMP);
> + __jump_label_update(key, iter, iter_stop);
> }
>
> return 0;

That is the fail; the arch_jump_label_transform() function (at least on
x86) double checks that we're changing the branch, so we cannot
unconditionally write whatever it should be.


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