Re: [PATCH v1] fs/super.c: Add NULL check for type in iterate_supers_type

[Christian Brauner]

On Wed, Apr 02, 2025 at 11:45:29AM +0800, Xiaole He wrote:
> The first several lines of iterate_supers_type are below:
> 
> 1 void iterate_supers_type(struct file_system_type *type,
> 2 	void (*f)(struct super_block *, void *), void *arg)
> 3 {
> 4 	struct super_block *sb, *p = NULL;
> 5
> 6 	spin_lock(&sb_lock);
> 7 	hlist_for_each_entry(sb, &type->fs_supers, s_instances) {
> 8 	...
> 9 }
> 
> The iterate_super_type is a exported symbol, and if iterate_supers_type
> is called with type of NULL, then there will be a NULL pointer
> dereference of argument type in line 7.
> 
> This patch fix above problem by adding NULL pointer check for argument
> type.
> 
> Signed-off-by: Xiaole He <hexiaole1994@xxxxxxx>
> ---

Both Al and James already pointed out that this check is unnecessary and
ultimately misleading. So we're not going to accept this patch.