[PATCH] livepatch: klp_disable_func returnes once it does not satisfy the condition

[PATCH] livepatch: klp_disable_func returnes once it does not satisfy the condition

[Minfei Huang]

From: Minfei Huang <mnfhuang@gmail.com>

It is more better that klp_disable_func returnes immediately, if
func->state and func->old_addr do not satisfy the condition.

We should robust the livepatch code, although the above situation never
happen in current code path.

Signed-off-by: Minfei Huang <mnfhuang@gmail.com>
---
 kernel/livepatch/core.c | 6 ++++--
 1 file changed, 4 insertions(+), 2 deletions(-)

diff --git a/kernel/livepatch/core.c b/kernel/livepatch/core.c
index c40ebcc..6e53441 100644
--- a/kernel/livepatch/core.c
+++ b/kernel/livepatch/core.c
@@ -348,8 +348,10 @@ static void klp_disable_func(struct klp_func *func)
 {
 	struct klp_ops *ops;
 
-	WARN_ON(func->state != KLP_ENABLED);
-	WARN_ON(!func->old_addr);
+	if (WARN_ON(func->state != KLP_ENABLED))
+		return;
+	if (WARN_ON(!func->old_addr))
+		return;
 
 	ops = klp_find_ops(func->old_addr);
 	if (WARN_ON(!ops))
-- 
2.2.2

Re: [PATCH] livepatch: klp_disable_func returnes once it does not satisfy the condition

[Josh Poimboeuf]

On Tue, Jul 14, 2015 at 11:15:37AM +0800, Minfei Huang wrote:
> From: Minfei Huang <mnfhuang@gmail.com>
> 
> It is more better that klp_disable_func returnes immediately, if
> func->state and func->old_addr do not satisfy the condition.
> 
> We should robust the livepatch code, although the above situation never
> happen in current code path.
> 
> Signed-off-by: Minfei Huang <mnfhuang@gmail.com>
> ---
>  kernel/livepatch/core.c | 6 ++++--
>  1 file changed, 4 insertions(+), 2 deletions(-)
> 
> diff --git a/kernel/livepatch/core.c b/kernel/livepatch/core.c
> index c40ebcc..6e53441 100644
> --- a/kernel/livepatch/core.c
> +++ b/kernel/livepatch/core.c
> @@ -348,8 +348,10 @@ static void klp_disable_func(struct klp_func *func)
>  {
>  	struct klp_ops *ops;
>  
> -	WARN_ON(func->state != KLP_ENABLED);
> -	WARN_ON(!func->old_addr);
> +	if (WARN_ON(func->state != KLP_ENABLED))
> +		return;
> +	if (WARN_ON(!func->old_addr))
> +		return;
>  
>  	ops = klp_find_ops(func->old_addr);
>  	if (WARN_ON(!ops))

Acked-by: Josh Poimboeuf <jpoimboe@redhat.com>

Re: [PATCH] livepatch: klp_disable_func returnes once it does not satisfy the condition

[Jiri Kosina]

On Tue, 14 Jul 2015, Minfei Huang wrote:

> From: Minfei Huang <mnfhuang@gmail.com>
> 
> It is more better that klp_disable_func returnes immediately, if
> func->state and func->old_addr do not satisfy the condition.
> 
> We should robust the livepatch code, although the above situation never
> happen in current code path.

I have reworded the changelog a little bit and applied to 
for-4.3/upstream.

Thanks,

-- 
Jiri Kosina
SUSE Labs