From: Kaitao Cheng <chengkaitao@kylinos.cn>

If a user holds ownership of a node in the middle of a list, they
can directly remove it from the list without strictly adhering to
deletion rules from the head or tail.

We have added an additional parameter bpf_list_head *head to
bpf_list_del, as the verifier requires the head parameter to
check whether the lock is being held.

This is typically paired with bpf_refcount. After calling
bpf_list_del, it is generally necessary to drop the reference to
the list node twice to prevent reference count leaks.

Signed-off-by: Kaitao Cheng <chengkaitao@kylinos.cn>
---
 kernel/bpf/helpers.c  | 30 +++++++++++++++++++++++-------
 kernel/bpf/verifier.c |  6 +++++-
 2 files changed, 28 insertions(+), 8 deletions(-)

diff --git a/kernel/bpf/helpers.c b/kernel/bpf/helpers.c
index 6eb6c82ed2ee..01b74c4ac00d 100644
--- a/kernel/bpf/helpers.c
+++ b/kernel/bpf/helpers.c
@@ -2426,20 +2426,23 @@ __bpf_kfunc int bpf_list_push_back_impl(struct bpf_list_head *head,
 	return __bpf_list_add(n, head, true, meta ? meta->record : NULL, off);
 }
 
-static struct bpf_list_node *__bpf_list_del(struct bpf_list_head *head, bool tail)
+static struct bpf_list_node *__bpf_list_del(struct bpf_list_head *head,
+					    struct list_head *n)
 {
-	struct list_head *n, *h = (void *)head;
+	struct list_head *h = (void *)head;
 	struct bpf_list_node_kern *node;
 
 	/* If list_head was 0-initialized by map, bpf_obj_init_field wasn't
 	 * called on its fields, so init here
 	 */
-	if (unlikely(!h->next))
+	if (unlikely(!h->next)) {
 		INIT_LIST_HEAD(h);
-	if (list_empty(h))
+		return NULL;
+	}
+
+	if (n == h)
 		return NULL;
 
-	n = tail ? h->prev : h->next;
 	node = container_of(n, struct bpf_list_node_kern, list_head);
 	if (WARN_ON_ONCE(READ_ONCE(node->owner) != head))
 		return NULL;
@@ -2451,12 +2454,24 @@ static struct bpf_list_node *__bpf_list_del(struct bpf_list_head *head, bool tai
 
 __bpf_kfunc struct bpf_list_node *bpf_list_pop_front(struct bpf_list_head *head)
 {
-	return __bpf_list_del(head, false);
+	struct list_head *h = (void *)head;
+
+	return __bpf_list_del(head, h->next);
 }
 
 __bpf_kfunc struct bpf_list_node *bpf_list_pop_back(struct bpf_list_head *head)
 {
-	return __bpf_list_del(head, true);
+	struct list_head *h = (void *)head;
+
+	return __bpf_list_del(head, h->prev);
+}
+
+__bpf_kfunc struct bpf_list_node *bpf_list_del(struct bpf_list_head *head,
+					       struct bpf_list_node *node)
+{
+	struct bpf_list_node_kern *kn = (void *)node;
+
+	return __bpf_list_del(head, &kn->list_head);
 }
 
 __bpf_kfunc struct bpf_list_node *bpf_list_front(struct bpf_list_head *head)
@@ -4545,6 +4560,7 @@ BTF_ID_FLAGS(func, bpf_list_push_front_impl)
 BTF_ID_FLAGS(func, bpf_list_push_back_impl)
 BTF_ID_FLAGS(func, bpf_list_pop_front, KF_ACQUIRE | KF_RET_NULL)
 BTF_ID_FLAGS(func, bpf_list_pop_back, KF_ACQUIRE | KF_RET_NULL)
+BTF_ID_FLAGS(func, bpf_list_del, KF_ACQUIRE | KF_RET_NULL)
 BTF_ID_FLAGS(func, bpf_list_front, KF_RET_NULL)
 BTF_ID_FLAGS(func, bpf_list_back, KF_RET_NULL)
 BTF_ID_FLAGS(func, bpf_task_acquire, KF_ACQUIRE | KF_RCU | KF_RET_NULL)
diff --git a/kernel/bpf/verifier.c b/kernel/bpf/verifier.c
index 67c09b43a497..c9557d3fb8dd 100644
--- a/kernel/bpf/verifier.c
+++ b/kernel/bpf/verifier.c
@@ -12461,6 +12461,7 @@ enum special_kfunc_type {
 	KF_bpf_list_push_back_impl,
 	KF_bpf_list_pop_front,
 	KF_bpf_list_pop_back,
+	KF_bpf_list_del,
 	KF_bpf_list_front,
 	KF_bpf_list_back,
 	KF_bpf_cast_to_kern_ctx,
@@ -12521,6 +12522,7 @@ BTF_ID(func, bpf_list_push_front_impl)
 BTF_ID(func, bpf_list_push_back_impl)
 BTF_ID(func, bpf_list_pop_front)
 BTF_ID(func, bpf_list_pop_back)
+BTF_ID(func, bpf_list_del)
 BTF_ID(func, bpf_list_front)
 BTF_ID(func, bpf_list_back)
 BTF_ID(func, bpf_cast_to_kern_ctx)
@@ -12996,6 +12998,7 @@ static bool is_bpf_list_api_kfunc(u32 btf_id)
 	       btf_id == special_kfunc_list[KF_bpf_list_push_back_impl] ||
 	       btf_id == special_kfunc_list[KF_bpf_list_pop_front] ||
 	       btf_id == special_kfunc_list[KF_bpf_list_pop_back] ||
+	       btf_id == special_kfunc_list[KF_bpf_list_del] ||
 	       btf_id == special_kfunc_list[KF_bpf_list_front] ||
 	       btf_id == special_kfunc_list[KF_bpf_list_back];
 }
@@ -13118,7 +13121,8 @@ static bool check_kfunc_is_graph_node_api(struct bpf_verifier_env *env,
 	switch (node_field_type) {
 	case BPF_LIST_NODE:
 		ret = (kfunc_btf_id == special_kfunc_list[KF_bpf_list_push_front_impl] ||
-		       kfunc_btf_id == special_kfunc_list[KF_bpf_list_push_back_impl]);
+		       kfunc_btf_id == special_kfunc_list[KF_bpf_list_push_back_impl] ||
+		       kfunc_btf_id == special_kfunc_list[KF_bpf_list_del]);
 		break;
 	case BPF_RB_NODE:
 		ret = (kfunc_btf_id == special_kfunc_list[KF_bpf_rbtree_remove] ||
-- 
2.50.1 (Apple Git-155)

On 8/3/26 21:46, Chengkaitao wrote:
> From: Kaitao Cheng <chengkaitao@kylinos.cn>
> 
> If a user holds ownership of a node in the middle of a list, they
> can directly remove it from the list without strictly adhering to
> deletion rules from the head or tail.
> 
> We have added an additional parameter bpf_list_head *head to
> bpf_list_del, as the verifier requires the head parameter to
> check whether the lock is being held.
> 
> This is typically paired with bpf_refcount. After calling
> bpf_list_del, it is generally necessary to drop the reference to
> the list node twice to prevent reference count leaks.
> 
> Signed-off-by: Kaitao Cheng <chengkaitao@kylinos.cn>
> ---
>  kernel/bpf/helpers.c  | 30 +++++++++++++++++++++++-------
>  kernel/bpf/verifier.c |  6 +++++-
>  2 files changed, 28 insertions(+), 8 deletions(-)
> 
> diff --git a/kernel/bpf/helpers.c b/kernel/bpf/helpers.c
> index 6eb6c82ed2ee..01b74c4ac00d 100644
> --- a/kernel/bpf/helpers.c
> +++ b/kernel/bpf/helpers.c
> @@ -2426,20 +2426,23 @@ __bpf_kfunc int bpf_list_push_back_impl(struct bpf_list_head *head,
>  	return __bpf_list_add(n, head, true, meta ? meta->record : NULL, off);
>  }
>  
> -static struct bpf_list_node *__bpf_list_del(struct bpf_list_head *head, bool tail)
> +static struct bpf_list_node *__bpf_list_del(struct bpf_list_head *head,
> +					    struct list_head *n)
>  {
> -	struct list_head *n, *h = (void *)head;
> +	struct list_head *h = (void *)head;
>  	struct bpf_list_node_kern *node;
>  
>  	/* If list_head was 0-initialized by map, bpf_obj_init_field wasn't
>  	 * called on its fields, so init here
>  	 */
> -	if (unlikely(!h->next))
> +	if (unlikely(!h->next)) {
>  		INIT_LIST_HEAD(h);
> -	if (list_empty(h))
> +		return NULL;
> +	}
> +
> +	if (n == h)
>  		return NULL;
>  
> -	n = tail ? h->prev : h->next;
>  	node = container_of(n, struct bpf_list_node_kern, list_head);
>  	if (WARN_ON_ONCE(READ_ONCE(node->owner) != head))
>  		return NULL;

This refactoring is worth, because the "struct list_head *n" seems
better than "bool tail".

But, such refactoring should be a preparatory patch. Importantly,
refactoring should not introduce functional changes.

Thanks,
Leon

> @@ -2451,12 +2454,24 @@ static struct bpf_list_node *__bpf_list_del(struct bpf_list_head *head, bool tai
>  
>  __bpf_kfunc struct bpf_list_node *bpf_list_pop_front(struct bpf_list_head *head)
>  {
> -	return __bpf_list_del(head, false);
> +	struct list_head *h = (void *)head;
> +
> +	return __bpf_list_del(head, h->next);
>  }
>  
>  __bpf_kfunc struct bpf_list_node *bpf_list_pop_back(struct bpf_list_head *head)
>  {
> -	return __bpf_list_del(head, true);
> +	struct list_head *h = (void *)head;
> +
> +	return __bpf_list_del(head, h->prev);
> +}
> +
> +__bpf_kfunc struct bpf_list_node *bpf_list_del(struct bpf_list_head *head,
> +					       struct bpf_list_node *node)
> +{
> +	struct bpf_list_node_kern *kn = (void *)node;
> +
> +	return __bpf_list_del(head, &kn->list_head);
>  }
>  
>  __bpf_kfunc struct bpf_list_node *bpf_list_front(struct bpf_list_head *head)
> @@ -4545,6 +4560,7 @@ BTF_ID_FLAGS(func, bpf_list_push_front_impl)
>  BTF_ID_FLAGS(func, bpf_list_push_back_impl)
>  BTF_ID_FLAGS(func, bpf_list_pop_front, KF_ACQUIRE | KF_RET_NULL)
>  BTF_ID_FLAGS(func, bpf_list_pop_back, KF_ACQUIRE | KF_RET_NULL)
> +BTF_ID_FLAGS(func, bpf_list_del, KF_ACQUIRE | KF_RET_NULL)
>  BTF_ID_FLAGS(func, bpf_list_front, KF_RET_NULL)
>  BTF_ID_FLAGS(func, bpf_list_back, KF_RET_NULL)
>  BTF_ID_FLAGS(func, bpf_task_acquire, KF_ACQUIRE | KF_RCU | KF_RET_NULL)
> diff --git a/kernel/bpf/verifier.c b/kernel/bpf/verifier.c
> index 67c09b43a497..c9557d3fb8dd 100644
> --- a/kernel/bpf/verifier.c
> +++ b/kernel/bpf/verifier.c
> @@ -12461,6 +12461,7 @@ enum special_kfunc_type {
>  	KF_bpf_list_push_back_impl,
>  	KF_bpf_list_pop_front,
>  	KF_bpf_list_pop_back,
> +	KF_bpf_list_del,
>  	KF_bpf_list_front,
>  	KF_bpf_list_back,
>  	KF_bpf_cast_to_kern_ctx,
> @@ -12521,6 +12522,7 @@ BTF_ID(func, bpf_list_push_front_impl)
>  BTF_ID(func, bpf_list_push_back_impl)
>  BTF_ID(func, bpf_list_pop_front)
>  BTF_ID(func, bpf_list_pop_back)
> +BTF_ID(func, bpf_list_del)
>  BTF_ID(func, bpf_list_front)
>  BTF_ID(func, bpf_list_back)
>  BTF_ID(func, bpf_cast_to_kern_ctx)
> @@ -12996,6 +12998,7 @@ static bool is_bpf_list_api_kfunc(u32 btf_id)
>  	       btf_id == special_kfunc_list[KF_bpf_list_push_back_impl] ||
>  	       btf_id == special_kfunc_list[KF_bpf_list_pop_front] ||
>  	       btf_id == special_kfunc_list[KF_bpf_list_pop_back] ||
> +	       btf_id == special_kfunc_list[KF_bpf_list_del] ||
>  	       btf_id == special_kfunc_list[KF_bpf_list_front] ||
>  	       btf_id == special_kfunc_list[KF_bpf_list_back];
>  }
> @@ -13118,7 +13121,8 @@ static bool check_kfunc_is_graph_node_api(struct bpf_verifier_env *env,
>  	switch (node_field_type) {
>  	case BPF_LIST_NODE:
>  		ret = (kfunc_btf_id == special_kfunc_list[KF_bpf_list_push_front_impl] ||
> -		       kfunc_btf_id == special_kfunc_list[KF_bpf_list_push_back_impl]);
> +		       kfunc_btf_id == special_kfunc_list[KF_bpf_list_push_back_impl] ||
> +		       kfunc_btf_id == special_kfunc_list[KF_bpf_list_del]);
>  		break;
>  	case BPF_RB_NODE:
>  		ret = (kfunc_btf_id == special_kfunc_list[KF_bpf_rbtree_remove] ||

On Mon, 9 Mar 2026 at 07:34, Leon Hwang <leon.hwang@linux.dev> wrote:
>
> On 8/3/26 21:46, Chengkaitao wrote:
> > From: Kaitao Cheng <chengkaitao@kylinos.cn>
> >
> > If a user holds ownership of a node in the middle of a list, they
> > can directly remove it from the list without strictly adhering to
> > deletion rules from the head or tail.
> >
> > We have added an additional parameter bpf_list_head *head to
> > bpf_list_del, as the verifier requires the head parameter to
> > check whether the lock is being held.
> >
> > This is typically paired with bpf_refcount. After calling
> > bpf_list_del, it is generally necessary to drop the reference to
> > the list node twice to prevent reference count leaks.
> >
> > Signed-off-by: Kaitao Cheng <chengkaitao@kylinos.cn>
> > ---
> >  kernel/bpf/helpers.c  | 30 +++++++++++++++++++++++-------
> >  kernel/bpf/verifier.c |  6 +++++-
> >  2 files changed, 28 insertions(+), 8 deletions(-)
> >
> > diff --git a/kernel/bpf/helpers.c b/kernel/bpf/helpers.c
> > index 6eb6c82ed2ee..01b74c4ac00d 100644
> > --- a/kernel/bpf/helpers.c
> > +++ b/kernel/bpf/helpers.c
> > @@ -2426,20 +2426,23 @@ __bpf_kfunc int bpf_list_push_back_impl(struct bpf_list_head *head,
> >       return __bpf_list_add(n, head, true, meta ? meta->record : NULL, off);
> >  }
> >
> > -static struct bpf_list_node *__bpf_list_del(struct bpf_list_head *head, bool tail)
> > +static struct bpf_list_node *__bpf_list_del(struct bpf_list_head *head,
> > +                                         struct list_head *n)
> >  {
> > -     struct list_head *n, *h = (void *)head;
> > +     struct list_head *h = (void *)head;
> >       struct bpf_list_node_kern *node;
> >
> >       /* If list_head was 0-initialized by map, bpf_obj_init_field wasn't
> >        * called on its fields, so init here
> >        */
> > -     if (unlikely(!h->next))
> > +     if (unlikely(!h->next)) {
> >               INIT_LIST_HEAD(h);
> > -     if (list_empty(h))
> > +             return NULL;
> > +     }
> > +
> > +     if (n == h)
> >               return NULL;

Couldn't you keep the list_empty(h) check after INIT_LIST_HEAD(h) as before?
And we don't need n == h either. You could add a comment that n will
never match h.
The verifier should ensure it, since it distinguishes the head and node types.

Let's say the head is uninit. Then list_empty(h) will catch that case.
Otherwise n might be NULL.

After list_empty(h) says false, we definitely have non-null n.
We just need to check list membership using the owner check, and then
we're good.
It will be a less noisy diff.

> >
> > -     n = tail ? h->prev : h->next;
> >       node = container_of(n, struct bpf_list_node_kern, list_head);
> >       if (WARN_ON_ONCE(READ_ONCE(node->owner) != head))
> >               return NULL;
>
> This refactoring is worth, because the "struct list_head *n" seems
> better than "bool tail".
>
> But, such refactoring should be a preparatory patch. Importantly,
> refactoring should not introduce functional changes.
>

I think it's fine. Let's address this and avoid too many respins now.
It isn't a lot of code anyway. You could mention in the commit log
that you chose to refactor __bpf_list_del though.



> Thanks,
> Leon
>
> > @@ -2451,12 +2454,24 @@ static struct bpf_list_node *__bpf_list_del(struct bpf_list_head *head, bool tai
> >
> >  __bpf_kfunc struct bpf_list_node *bpf_list_pop_front(struct bpf_list_head *head)
> >  {
> > -     return __bpf_list_del(head, false);
> > +     struct list_head *h = (void *)head;
> > +
> > +     return __bpf_list_del(head, h->next);
> >  }
> >
> >  __bpf_kfunc struct bpf_list_node *bpf_list_pop_back(struct bpf_list_head *head)
> >  {
> > -     return __bpf_list_del(head, true);
> > +     struct list_head *h = (void *)head;
> > +
> > +     return __bpf_list_del(head, h->prev);
> > +}
> > +
> > +__bpf_kfunc struct bpf_list_node *bpf_list_del(struct bpf_list_head *head,
> > +                                            struct bpf_list_node *node)
> > +{
> > +     struct bpf_list_node_kern *kn = (void *)node;
> > +
> > +     return __bpf_list_del(head, &kn->list_head);
> >  }
> >
> >  __bpf_kfunc struct bpf_list_node *bpf_list_front(struct bpf_list_head *head)
> > @@ -4545,6 +4560,7 @@ BTF_ID_FLAGS(func, bpf_list_push_front_impl)
> >  BTF_ID_FLAGS(func, bpf_list_push_back_impl)
> >  BTF_ID_FLAGS(func, bpf_list_pop_front, KF_ACQUIRE | KF_RET_NULL)
> >  BTF_ID_FLAGS(func, bpf_list_pop_back, KF_ACQUIRE | KF_RET_NULL)
> > +BTF_ID_FLAGS(func, bpf_list_del, KF_ACQUIRE | KF_RET_NULL)
> >  BTF_ID_FLAGS(func, bpf_list_front, KF_RET_NULL)
> >  BTF_ID_FLAGS(func, bpf_list_back, KF_RET_NULL)
> >  BTF_ID_FLAGS(func, bpf_task_acquire, KF_ACQUIRE | KF_RCU | KF_RET_NULL)
> > diff --git a/kernel/bpf/verifier.c b/kernel/bpf/verifier.c
> > index 67c09b43a497..c9557d3fb8dd 100644
> > --- a/kernel/bpf/verifier.c
> > +++ b/kernel/bpf/verifier.c
> > @@ -12461,6 +12461,7 @@ enum special_kfunc_type {
> >       KF_bpf_list_push_back_impl,
> >       KF_bpf_list_pop_front,
> >       KF_bpf_list_pop_back,
> > +     KF_bpf_list_del,
> >       KF_bpf_list_front,
> >       KF_bpf_list_back,
> >       KF_bpf_cast_to_kern_ctx,
> > @@ -12521,6 +12522,7 @@ BTF_ID(func, bpf_list_push_front_impl)
> >  BTF_ID(func, bpf_list_push_back_impl)
> >  BTF_ID(func, bpf_list_pop_front)
> >  BTF_ID(func, bpf_list_pop_back)
> > +BTF_ID(func, bpf_list_del)
> >  BTF_ID(func, bpf_list_front)
> >  BTF_ID(func, bpf_list_back)
> >  BTF_ID(func, bpf_cast_to_kern_ctx)
> > @@ -12996,6 +12998,7 @@ static bool is_bpf_list_api_kfunc(u32 btf_id)
> >              btf_id == special_kfunc_list[KF_bpf_list_push_back_impl] ||
> >              btf_id == special_kfunc_list[KF_bpf_list_pop_front] ||
> >              btf_id == special_kfunc_list[KF_bpf_list_pop_back] ||
> > +            btf_id == special_kfunc_list[KF_bpf_list_del] ||
> >              btf_id == special_kfunc_list[KF_bpf_list_front] ||
> >              btf_id == special_kfunc_list[KF_bpf_list_back];
> >  }
> > @@ -13118,7 +13121,8 @@ static bool check_kfunc_is_graph_node_api(struct bpf_verifier_env *env,
> >       switch (node_field_type) {
> >       case BPF_LIST_NODE:
> >               ret = (kfunc_btf_id == special_kfunc_list[KF_bpf_list_push_front_impl] ||
> > -                    kfunc_btf_id == special_kfunc_list[KF_bpf_list_push_back_impl]);
> > +                    kfunc_btf_id == special_kfunc_list[KF_bpf_list_push_back_impl] ||
> > +                    kfunc_btf_id == special_kfunc_list[KF_bpf_list_del]);
> >               break;
> >       case BPF_RB_NODE:
> >               ret = (kfunc_btf_id == special_kfunc_list[KF_bpf_rbtree_remove] ||
>
>

On Tue, 10 Mar 2026 at 21:10, Kumar Kartikeya Dwivedi <memxor@gmail.com> wrote:
>
> On Mon, 9 Mar 2026 at 07:34, Leon Hwang <leon.hwang@linux.dev> wrote:
> >
> > On 8/3/26 21:46, Chengkaitao wrote:
> > > From: Kaitao Cheng <chengkaitao@kylinos.cn>
> > >
> > > If a user holds ownership of a node in the middle of a list, they
> > > can directly remove it from the list without strictly adhering to
> > > deletion rules from the head or tail.
> > >
> > > We have added an additional parameter bpf_list_head *head to
> > > bpf_list_del, as the verifier requires the head parameter to
> > > check whether the lock is being held.
> > >
> > > This is typically paired with bpf_refcount. After calling
> > > bpf_list_del, it is generally necessary to drop the reference to
> > > the list node twice to prevent reference count leaks.
> > >
> > > Signed-off-by: Kaitao Cheng <chengkaitao@kylinos.cn>
> > > ---
> > >  kernel/bpf/helpers.c  | 30 +++++++++++++++++++++++-------
> > >  kernel/bpf/verifier.c |  6 +++++-
> > >  2 files changed, 28 insertions(+), 8 deletions(-)
> > >
> > > diff --git a/kernel/bpf/helpers.c b/kernel/bpf/helpers.c
> > > index 6eb6c82ed2ee..01b74c4ac00d 100644
> > > --- a/kernel/bpf/helpers.c
> > > +++ b/kernel/bpf/helpers.c
> > > @@ -2426,20 +2426,23 @@ __bpf_kfunc int bpf_list_push_back_impl(struct bpf_list_head *head,
> > >       return __bpf_list_add(n, head, true, meta ? meta->record : NULL, off);
> > >  }
> > >
> > > -static struct bpf_list_node *__bpf_list_del(struct bpf_list_head *head, bool tail)
> > > +static struct bpf_list_node *__bpf_list_del(struct bpf_list_head *head,
> > > +                                         struct list_head *n)
> > >  {
> > > -     struct list_head *n, *h = (void *)head;
> > > +     struct list_head *h = (void *)head;
> > >       struct bpf_list_node_kern *node;
> > >
> > >       /* If list_head was 0-initialized by map, bpf_obj_init_field wasn't
> > >        * called on its fields, so init here
> > >        */
> > > -     if (unlikely(!h->next))
> > > +     if (unlikely(!h->next)) {
> > >               INIT_LIST_HEAD(h);
> > > -     if (list_empty(h))
> > > +             return NULL;
> > > +     }
> > > +
> > > +     if (n == h)
> > >               return NULL;
>
> Couldn't you keep the list_empty(h) check after INIT_LIST_HEAD(h) as before?
> And we don't need n == h either. You could add a comment that n will
> never match h.
> The verifier should ensure it, since it distinguishes the head and node types.
>
> Let's say the head is uninit. Then list_empty(h) will catch that case.
> Otherwise n might be NULL.
>
> After list_empty(h) says false, we definitely have non-null n.
> We just need to check list membership using the owner check, and then
> we're good.
> It will be a less noisy diff.
>
> > >
> > > -     n = tail ? h->prev : h->next;
> > >       node = container_of(n, struct bpf_list_node_kern, list_head);
> > >       if (WARN_ON_ONCE(READ_ONCE(node->owner) != head))
> > >               return NULL;
> >
> > This refactoring is worth, because the "struct list_head *n" seems
> > better than "bool tail".
> >
> > But, such refactoring should be a preparatory patch. Importantly,
> > refactoring should not introduce functional changes.
> >
>
> I think it's fine. Let's address this and avoid too many respins now.
> It isn't a lot of code anyway. You could mention in the commit log
> that you chose to refactor __bpf_list_del though.
>

Just to make it clearer, since I feel the language above might be a
bit confusing:
Let's not add more churn and just fix the issues in the existing set,
and try to move towards landing this.
We are quite close, and it's been 7 iterations already.

The bit about the non-owning refs pointed out by the AI bot, you can
do it as a follow up on top after this is accepted.

> [...]