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Tue, 03 Mar 2026 19:16:35 -0800 (PST) Received: from localhost.localdomain ([116.128.244.171]) by smtp.gmail.com with ESMTPSA id 98e67ed59e1d1-3599c3ab946sm3610648a91.13.2026.03.03.19.16.28 (version=TLS1_3 cipher=TLS_CHACHA20_POLY1305_SHA256 bits=256/256); Tue, 03 Mar 2026 19:16:35 -0800 (PST) From: Chengkaitao To: martin.lau@linux.dev, ast@kernel.org, daniel@iogearbox.net, andrii@kernel.org, eddyz87@gmail.com, song@kernel.org, yonghong.song@linux.dev, john.fastabend@gmail.com, kpsingh@kernel.org, sdf@fomichev.me, haoluo@google.com, jolsa@kernel.org, shuah@kernel.org, chengkaitao@kylinos.cn, linux-kselftest@vger.kernel.org Cc: bpf@vger.kernel.org, linux-kernel@vger.kernel.org Subject: [PATCH v5 2/6] selftests/bpf: Add test cases for bpf_list_del Date: Wed, 4 Mar 2026 11:16:02 +0800 Message-ID: <20260304031606.43884-3-pilgrimtao@gmail.com> X-Mailer: git-send-email 2.50.1 In-Reply-To: <20260304031606.43884-1-pilgrimtao@gmail.com> References: <20260304031606.43884-1-pilgrimtao@gmail.com> Precedence: bulk X-Mailing-List: bpf@vger.kernel.org List-Id: List-Subscribe: List-Unsubscribe: MIME-Version: 1.0 Content-Transfer-Encoding: 8bit From: Kaitao Cheng 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. Signed-off-by: Kaitao Cheng --- .../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) -- 2.50.1 (Apple Git-155)