On 3/3/26 21:52, Chengkaitao wrote: > From: Kaitao Cheng <[email protected]> > > Add a node to both an rbtree and a list, retrieve the node from > the rbtree, use the obtained node pointer to remove it from the > list, and finally free the node. > > To verify the validity of bpf_list_del, also expect the verifier > to reject calls to bpf_list_del made without holding the spin_lock. >
To avoid the churn of renaming test_bpf_list_del() in patch #4, it would be better to fold patches #2, #4, and #6 into one patch. Thanks, Leon > Signed-off-by: Kaitao Cheng <[email protected]> > --- > .../testing/selftests/bpf/bpf_experimental.h | 11 +++ > .../selftests/bpf/progs/refcounted_kptr.c | 71 +++++++++++++++++++ > 2 files changed, 82 insertions(+) > > diff --git a/tools/testing/selftests/bpf/bpf_experimental.h > b/tools/testing/selftests/bpf/bpf_experimental.h > index 4b7210c318dd..54ec9d307fdc 100644 > --- a/tools/testing/selftests/bpf/bpf_experimental.h > +++ b/tools/testing/selftests/bpf/bpf_experimental.h > @@ -99,6 +99,17 @@ extern struct bpf_list_node *bpf_list_pop_front(struct > bpf_list_head *head) __ks > */ > extern struct bpf_list_node *bpf_list_pop_back(struct bpf_list_head *head) > __ksym; > > +/* Description > + * Remove 'node' from the BPF linked list with head 'head'. > + * The node must be in the list. Caller receives ownership of the > + * removed node and must release it with bpf_obj_drop. > + * Returns > + * Pointer to the removed bpf_list_node, or NULL if 'node' is NULL > + * or not in the list. > + */ > +extern struct bpf_list_node *bpf_list_del(struct bpf_list_head *head, > + struct bpf_list_node *node) __ksym; > + > /* Description > * Remove 'node' from rbtree with root 'root' > * Returns > diff --git a/tools/testing/selftests/bpf/progs/refcounted_kptr.c > b/tools/testing/selftests/bpf/progs/refcounted_kptr.c > index 1aca85d86aeb..ac7672cfefb8 100644 > --- a/tools/testing/selftests/bpf/progs/refcounted_kptr.c > +++ b/tools/testing/selftests/bpf/progs/refcounted_kptr.c > @@ -367,6 +367,77 @@ long insert_rbtree_and_stash__del_tree_##rem_tree(void > *ctx) \ > INSERT_STASH_READ(true, "insert_stash_read: remove from tree"); > INSERT_STASH_READ(false, "insert_stash_read: don't remove from tree"); > > +/* Insert node_data into both rbtree and list, remove from tree, then remove > + * from list via bpf_list_del using the node obtained from the tree. > + */ > +SEC("tc") > +__description("test_bpf_list_del: remove an arbitrary node from the list") > +__success __retval(0) > +long test_bpf_list_del(void *ctx) > +{ > + long err; > + struct bpf_rb_node *rb; > + struct bpf_list_node *l; > + struct node_data *n; > + > + err = __insert_in_tree_and_list(&head, &root, &lock); > + if (err) > + return err; > + > + bpf_spin_lock(&lock); > + rb = bpf_rbtree_first(&root); > + if (!rb) { > + bpf_spin_unlock(&lock); > + return -4; > + } > + > + rb = bpf_rbtree_remove(&root, rb); > + if (!rb) { > + bpf_spin_unlock(&lock); > + return -5; > + } > + > + n = container_of(rb, struct node_data, r); > + l = bpf_list_del(&head, &n->l); > + bpf_spin_unlock(&lock); > + bpf_obj_drop(n); > + if (!l) > + return -6; > + > + bpf_obj_drop(container_of(l, struct node_data, l)); > + return 0; > +} > + > +SEC("?tc") > +__failure __msg("bpf_spin_lock at off=32 must be held for bpf_list_head") > +long list_del_without_lock_fail(void *ctx) > +{ > + struct bpf_rb_node *rb; > + struct bpf_list_node *l; > + struct node_data *n; > + > + bpf_spin_lock(&lock); > + rb = bpf_rbtree_first(&root); > + if (!rb) { > + bpf_spin_unlock(&lock); > + return -4; > + } > + > + rb = bpf_rbtree_remove(&root, rb); > + bpf_spin_unlock(&lock); > + if (!rb) > + return -5; > + > + n = container_of(rb, struct node_data, r); > + l = bpf_list_del(&head, &n->l); > + bpf_obj_drop(n); > + if (!l) > + return -6; > + > + bpf_obj_drop(container_of(l, struct node_data, l)); > + return 0; > +} > + > SEC("tc") > __success > long rbtree_refcounted_node_ref_escapes(void *ctx)
