Re: [PATCH] vlan: Avoid crashing the kernel

From: Stephen Hemminger
Date: Mon Jun 07 2021 - 11:33:34 EST


On Sun, 6 Jun 2021 20:08:39 -0700
13145886936@xxxxxxx wrote:

> From: gushengxian <gushengxian@xxxxxxxxxx>
>
> Avoid crashing the kernel, try using WARN_ON & recovery code
> rather than BUG() or BUG_ON().
>
> Signed-off-by: gushengxian <gushengxian@xxxxxxxxxx>
> ---
> net/8021q/vlan.c | 4 ++--
> 1 file changed, 2 insertions(+), 2 deletions(-)
>
> diff --git a/net/8021q/vlan.c b/net/8021q/vlan.c
> index 4cdf8416869d..6e784fd8795b 100644
> --- a/net/8021q/vlan.c
> +++ b/net/8021q/vlan.c
> @@ -97,7 +97,7 @@ void unregister_vlan_dev(struct net_device *dev, struct list_head *head)
> ASSERT_RTNL();
>
> vlan_info = rtnl_dereference(real_dev->vlan_info);
> - BUG_ON(!vlan_info);
> + WARN_ON(!vlan_info);
>
> grp = &vlan_info->grp;

NACK

You change turns bug on into warning and crash from null pointer dereference.