From: Kaitao Cheng <[email protected]> Extend refcounted_kptr with tests for bpf_list_add (including prev from bpf_list_front and bpf_refcount_acquire), bpf_list_del (including node from bpf_rbtree_remove and bpf_refcount_acquire), bpf_list_empty, bpf_list_is_first/last, and push_back on uninit head.
To verify the validity of bpf_list_del/add, the test also expects the verifier to reject calls to bpf_list_del/add made without holding the spin_lock. Signed-off-by: Kaitao Cheng <[email protected]> --- .../testing/selftests/bpf/bpf_experimental.h | 16 + .../selftests/bpf/progs/refcounted_kptr.c | 311 ++++++++++++++++++ 2 files changed, 327 insertions(+) diff --git a/tools/testing/selftests/bpf/bpf_experimental.h b/tools/testing/selftests/bpf/bpf_experimental.h index 44466acf8083..5821f0000e1f 100644 --- a/tools/testing/selftests/bpf/bpf_experimental.h +++ b/tools/testing/selftests/bpf/bpf_experimental.h @@ -85,6 +85,22 @@ extern int bpf_list_push_back_impl(struct bpf_list_head *head, /* Convenience macro to wrap over bpf_list_push_back_impl */ #define bpf_list_push_back(head, node) bpf_list_push_back_impl(head, node, NULL, 0) +/* Description + * Insert 'new' after 'prev' in the BPF linked list with head 'head'. + * The bpf_spin_lock protecting the list must be held. 'prev' must already + * be in that list; 'new' must not be in any list. The 'meta' and 'off' + * parameters are rewritten by the verifier, no need for BPF programs to + * set them. + * Returns + * 0 on success, -EINVAL if head is NULL, prev is not in the list with head, + * or new is already in a list. + */ +extern int bpf_list_add_impl(struct bpf_list_head *head, struct bpf_list_node *new, + struct bpf_list_node *prev, void *meta, __u64 off) __ksym; + +/* Convenience macro to wrap over bpf_list_add_impl */ +#define bpf_list_add(head, new, prev) bpf_list_add_impl(head, new, prev, NULL, 0) + /* Description * Remove the entry at the beginning of the BPF linked list. * Returns diff --git a/tools/testing/selftests/bpf/progs/refcounted_kptr.c b/tools/testing/selftests/bpf/progs/refcounted_kptr.c index c847398837cc..e5558994a76d 100644 --- a/tools/testing/selftests/bpf/progs/refcounted_kptr.c +++ b/tools/testing/selftests/bpf/progs/refcounted_kptr.c @@ -367,6 +367,317 @@ 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"); +SEC("tc") +__description("list_empty_test: list empty before add, non-empty after add") +__success __retval(0) +int list_empty_test(void *ctx) +{ + struct node_data *node_new; + + bpf_spin_lock(&lock); + if (!bpf_list_empty(&head)) { + bpf_spin_unlock(&lock); + return -1; + } + bpf_spin_unlock(&lock); + + node_new = bpf_obj_new(typeof(*node_new)); + if (!node_new) + return -2; + + bpf_spin_lock(&lock); + bpf_list_push_front(&head, &node_new->l); + + if (bpf_list_empty(&head)) { + bpf_spin_unlock(&lock); + return -3; + } + bpf_spin_unlock(&lock); + return 0; +} + +static struct node_data *__add_in_list(struct bpf_list_head *head, + struct bpf_spin_lock *lock) +{ + struct node_data *node_new, *node_ref; + + node_new = bpf_obj_new(typeof(*node_new)); + if (!node_new) + return NULL; + + node_ref = bpf_refcount_acquire(node_new); + + bpf_spin_lock(lock); + bpf_list_push_front(head, &node_new->l); + bpf_spin_unlock(lock); + return node_ref; +} + +SEC("tc") +__description("list_is_edge_test: is_first on first node, is_last on last node") +__success __retval(0) +int list_is_edge_test(void *ctx) +{ + struct node_data *node_first, *node_last; + int err = 0; + + node_last = __add_in_list(&head, &lock); + if (!node_last) + return -1; + + node_first = __add_in_list(&head, &lock); + if (!node_first) { + bpf_obj_drop(node_last); + return -2; + } + + bpf_spin_lock(&lock); + if (!bpf_list_is_first(&head, &node_first->l)) { + err = -3; + goto fail; + } + if (!bpf_list_is_last(&head, &node_last->l)) + err = -4; + +fail: + bpf_spin_unlock(&lock); + bpf_obj_drop(node_first); + bpf_obj_drop(node_last); + return err; +} + +SEC("tc") +__description("list_del_test1: del returns removed nodes") +__success __retval(0) +int list_del_test1(void *ctx) +{ + struct node_data *node_first, *node_last; + struct bpf_list_node *bpf_node_first, *bpf_node_last; + int err = 0; + + node_last = __add_in_list(&head, &lock); + if (!node_last) + return -1; + + node_first = __add_in_list(&head, &lock); + if (!node_first) { + bpf_obj_drop(node_last); + return -2; + } + + bpf_spin_lock(&lock); + bpf_node_last = bpf_list_del(&head, &node_last->l); + bpf_node_first = bpf_list_del(&head, &node_first->l); + bpf_spin_unlock(&lock); + + if (bpf_node_first) + bpf_obj_drop(container_of(bpf_node_first, struct node_data, l)); + else + err = -3; + + if (bpf_node_last) + bpf_obj_drop(container_of(bpf_node_last, struct node_data, l)); + else + err = -4; + + bpf_obj_drop(node_first); + bpf_obj_drop(node_last); + return err; +} + +SEC("tc") +__description("list_del_test2: remove an arbitrary node from the list") +__success __retval(0) +int list_del_test2(void *ctx) +{ + struct bpf_rb_node *rb; + struct bpf_list_node *l; + struct node_data *n; + long err; + + 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") +__description("list_add_test1: insert new node after prev") +__success __retval(0) +int list_add_test1(void *ctx) +{ + struct node_data *node_first; + struct node_data *new_node; + long err = 0; + + node_first = __add_in_list(&head, &lock); + if (!node_first) + return -1; + + new_node = bpf_obj_new(typeof(*new_node)); + if (!new_node) { + err = -2; + goto fail; + } + + bpf_spin_lock(&lock); + err = bpf_list_add(&head, &new_node->l, &node_first->l); + bpf_spin_unlock(&lock); + if (err) { + err = -3; + goto fail; + } + +fail: + bpf_obj_drop(node_first); + return 0; +} + +SEC("tc") +__description("list_add_test2: list_add accepts list_front return value as prev") +__success __retval(0) +int list_add_test2(void *ctx) +{ + struct node_data *new_node, *tmp; + struct bpf_list_node *bpf_node; + long err = 0; + + tmp = __add_in_list(&head, &lock); + if (!tmp) + return -1; + + new_node = bpf_obj_new(typeof(*new_node)); + if (!new_node) { + err = -2; + goto fail; + } + + bpf_spin_lock(&lock); + bpf_node = bpf_list_front(&head); + if (!bpf_node) { + bpf_spin_unlock(&lock); + bpf_obj_drop(new_node); + err = -3; + goto fail; + } + + err = bpf_list_add(&head, &new_node->l, bpf_node); + bpf_spin_unlock(&lock); + if (err) { + err = -4; + goto fail; + } + +fail: + bpf_obj_drop(tmp); + return err; +} + +struct uninit_head_val { + struct bpf_spin_lock lock; + struct bpf_list_head head __contains(node_data, l); +}; + +struct { + __uint(type, BPF_MAP_TYPE_ARRAY); + __type(key, int); + __type(value, struct uninit_head_val); + __uint(max_entries, 1); +} uninit_head_map SEC(".maps"); + +SEC("tc") +__description("list_push_back_uninit_head: push_back on 0-initialized list head") +__success __retval(0) +int list_push_back_uninit_head(void *ctx) +{ + struct uninit_head_val *st; + struct node_data *node; + int ret = -1, key = 0; + + st = bpf_map_lookup_elem(&uninit_head_map, &key); + if (!st) + return -1; + + node = bpf_obj_new(typeof(*node)); + if (!node) + return -1; + + bpf_spin_lock(&st->lock); + ret = bpf_list_push_back(&st->head, &node->l); + bpf_spin_unlock(&st->lock); + + return ret; +} + +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); + bpf_spin_unlock(&lock); + if (!rb) + return -1; + + n = container_of(rb, struct node_data, r); + /* Error case: delete list node without holding lock */ + l = bpf_list_del(&head, &n->l); + if (!l) + return -2; + 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_add_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); + l = bpf_list_front(&head); + bpf_spin_unlock(&lock); + if (!rb || !l) + return -1; + + n = container_of(l, struct node_data, l); + /* Error case: add list node without holding lock */ + if (bpf_list_add(&head, &n->l, l)) + return -2; + + return 0; +} + SEC("tc") __success long rbtree_refcounted_node_ref_escapes(void *ctx) -- 2.50.1 (Apple Git-155)
