Re: [PATCH 2/2] livepatch: __klp_disable_patch() should never be called for disabled patches

[Miroslav Benes]

On Fri, 20 Oct 2017, Petr Mladek wrote:

> __klp_disable_patch() should never be called when the patch is not
> enabled. Let's add the same warning that we have in __klp_enable_patch().
> 
> This allows to remove the check when calling klp_pre_unpatch_callback().
> It was strange anyway because it repeatedly checked per-patch flag
> for each patched object.
> 
> Signed-off-by: Petr Mladek <pmladek@xxxxxxxx>

Heh, this is not a new thing. See 
http://lkml.kernel.org/r/20141128170735.GD32376@xxxxxxxxxxxxxxx

I don't know why it got lost. Those were crazy times...

Miroslav

> ---
>  kernel/livepatch/core.c | 5 ++++-
>  1 file changed, 4 insertions(+), 1 deletion(-)
> 
> diff --git a/kernel/livepatch/core.c b/kernel/livepatch/core.c
> index eb134479c394..287f71e9dbfe 100644
> --- a/kernel/livepatch/core.c
> +++ b/kernel/livepatch/core.c
> @@ -282,6 +282,9 @@ static int __klp_disable_patch(struct klp_patch *patch)
>  {
>  	struct klp_object *obj;
>  
> +	if (WARN_ON(!patch->enabled))
> +		return -EINVAL;
> +
>  	if (klp_transition_patch)
>  		return -EBUSY;
>  
> @@ -293,7 +296,7 @@ static int __klp_disable_patch(struct klp_patch *patch)
>  	klp_init_transition(patch, KLP_UNPATCHED);
>  
>  	klp_for_each_object(patch, obj)
> -		if (patch->enabled && obj->patched)
> +		if (obj->patched)
>  			klp_pre_unpatch_callback(obj);
>  
>  	/*
> -- 
> 1.8.5.6
>