[PATCH net] ionic: catch failure from devlink_alloc

[PATCH net] ionic: catch failure from devlink_alloc

[Shannon Nelson]

Add a check for NULL on the alloc return.  If devlink_alloc() fails and
we try to use devlink_priv() on the NULL return, the kernel gets very
unhappy and panics. With this fix, the driver load will still fail,
but at least it won't panic the kernel.

Fixes: 919d13a7e455 ("devlink: Set device as early as possible")
Signed-off-by: Shannon Nelson <shannon.nelson@amd.com>
---
 drivers/net/ethernet/pensando/ionic/ionic_devlink.c | 2 ++
 1 file changed, 2 insertions(+)

diff --git a/drivers/net/ethernet/pensando/ionic/ionic_devlink.c b/drivers/net/ethernet/pensando/ionic/ionic_devlink.c
index e6ff757895ab..4ec66a6be073 100644
--- a/drivers/net/ethernet/pensando/ionic/ionic_devlink.c
+++ b/drivers/net/ethernet/pensando/ionic/ionic_devlink.c
@@ -61,6 +61,8 @@ struct ionic *ionic_devlink_alloc(struct device *dev)
 	struct devlink *dl;
 
 	dl = devlink_alloc(&ionic_dl_ops, sizeof(struct ionic), dev);
+	if (!dl)
+		return NULL;
 
 	return devlink_priv(dl);
 }
-- 
2.17.1

Re: [PATCH net] ionic: catch failure from devlink_alloc

[Simon Horman]

On Tue, Feb 28, 2023 at 05:36:23PM -0800, Shannon Nelson wrote:
> Add a check for NULL on the alloc return.  If devlink_alloc() fails and
> we try to use devlink_priv() on the NULL return, the kernel gets very
> unhappy and panics. With this fix, the driver load will still fail,
> but at least it won't panic the kernel.
> 
> Fixes: 919d13a7e455 ("devlink: Set device as early as possible")

Although the reference commit touched the devlink_alloc() line,
I think the bug was already there, introduced by:

df69ba43217d ("ionic: Add basic framework for IONIC Network device driver")

The code change looks good to me :)

> Signed-off-by: Shannon Nelson <shannon.nelson@amd.com>
> ---
>  drivers/net/ethernet/pensando/ionic/ionic_devlink.c | 2 ++
>  1 file changed, 2 insertions(+)
> 
> diff --git a/drivers/net/ethernet/pensando/ionic/ionic_devlink.c b/drivers/net/ethernet/pensando/ionic/ionic_devlink.c
> index e6ff757895ab..4ec66a6be073 100644
> --- a/drivers/net/ethernet/pensando/ionic/ionic_devlink.c
> +++ b/drivers/net/ethernet/pensando/ionic/ionic_devlink.c
> @@ -61,6 +61,8 @@ struct ionic *ionic_devlink_alloc(struct device *dev)
>  	struct devlink *dl;
>  
>  	dl = devlink_alloc(&ionic_dl_ops, sizeof(struct ionic), dev);
> +	if (!dl)
> +		return NULL;
>  
>  	return devlink_priv(dl);
>  }
> -- 
> 2.17.1
>