kernel/linux.git/tools/testing/selftests/bpf/prog_tests/percpu_alloc.c, branch linux-7.0.y

selftests/bpf: Harden cpu flags test for lru_percpu_hash map

2026-01-26T18:59:07+00:00

CI occasionally reports failures in the percpu_alloc/cpu_flag_lru_percpu_hash selftest, for example: First test_progs failure (test_progs_no_alu32-x86_64-llvm-21): #264/15 percpu_alloc/cpu_flag_lru_percpu_hash ... test_percpu_map_op_cpu_flag:FAIL:bpf_map_lookup_batch value on specified cpu unexpected bpf_map_lookup_batch value on specified cpu: actual 0 != expected 3735929054 The unexpected value indicates that an element was removed from the map. However, the test never calls delete_elem(), so the only possible cause is LRU eviction. This can happen when the current task migrates to another CPU: an update_elem() triggers eviction because there is no available LRU node on local freelist and global freelist. Harden the test against this behavior by provisioning sufficient spare elements. Set max_entries to 'nr_cpus * 2' and restrict the test to using the first nr_cpus entries, ensuring that updates do not spuriously trigger LRU eviction. Signed-off-by: Leon Hwang Signed-off-by: Martin KaFai Lau Link: https://patch.msgid.link/20260119133417.19739-1-leon.hwang@linux.dev

selftests/bpf: Add cases to test BPF_F_CPU and BPF_F_ALL_CPUS flags

2026-01-07T04:48:32+00:00

Add test coverage for the new BPF_F_CPU and BPF_F_ALL_CPUS flags support in percpu maps. The following APIs are exercised: * bpf_map_update_batch() * bpf_map_lookup_batch() * bpf_map_update_elem() * bpf_map__update_elem() * bpf_map_lookup_elem_flags() * bpf_map__lookup_elem() For lru_percpu_hash map, set max_entries to 'libbpf_num_possible_cpus() + 1' and only use the first 'libbpf_num_possible_cpus()' entries. This ensures a spare entry is always available in the LRU free list, avoiding eviction. When updating an existing key in lru_percpu_hash map: 1. l_new = prealloc_lru_pop(); /* Borrow from free list */ 2. l_old = lookup_elem_raw(); /* Found, key exists */ 3. pcpu_copy_value(); /* In-place update */ 4. bpf_lru_push_free(); /* Return l_new to free list */ Also add negative tests to verify that non-percpu array and hash maps reject the BPF_F_CPU and BPF_F_ALL_CPUS flags. Signed-off-by: Leon Hwang Link: https://lore.kernel.org/r/20260107022022.12843-8-leon.hwang@linux.dev Signed-off-by: Alexei Starovoitov

selftests/bpf: Improve percpu_alloc test robustness

2023-10-16T11:49:18+00:00

Make these non-serial tests filter BPF programs by intended PID of a test runner process. This makes it isolated from other parallel tests that might interfere accidentally. Signed-off-by: Andrii Nakryiko Signed-off-by: Daniel Borkmann Acked-by: John Fastabend Acked-by: Eduard Zingerman Link: https://lore.kernel.org/bpf/20231011223728.3188086-2-andrii@kernel.org

selftests/bpf: Add some negative tests

2023-09-08T15:42:18+00:00

Add a few negative tests for common mistakes with using percpu kptr including: - store to percpu kptr. - type mistach in bpf_kptr_xchg arguments. - sleepable prog with untrusted arg for bpf_this_cpu_ptr(). - bpf_percpu_obj_new && bpf_obj_drop, and bpf_obj_new && bpf_percpu_obj_drop - struct with ptr for bpf_percpu_obj_new - struct with special field (e.g., bpf_spin_lock) for bpf_percpu_obj_new Signed-off-by: Yonghong Song Link: https://lore.kernel.org/r/20230827152832.2002421-1-yonghong.song@linux.dev Signed-off-by: Alexei Starovoitov

selftests/bpf: Add tests for cgrp_local_storage with local percpu kptr

2023-09-08T15:42:18+00:00

Add a non-sleepable cgrp_local_storage test with percpu kptr. The test does allocation of percpu data, assigning values to percpu data and retrieval of percpu data. The de-allocation of percpu data is done when the map is freed. Signed-off-by: Yonghong Song Link: https://lore.kernel.org/r/20230827152827.2001784-1-yonghong.song@linux.dev Signed-off-by: Alexei Starovoitov

selftests/bpf: Add tests for array map with local percpu kptr

2023-09-08T15:42:18+00:00

Add non-sleepable and sleepable tests with percpu kptr. For non-sleepable test, four programs are executed in the order of: 1. allocate percpu data. 2. assign values to percpu data. 3. retrieve percpu data. 4. de-allocate percpu data. The sleepable prog tried to exercise all above 4 steps in a single prog. Also for sleepable prog, rcu_read_lock is needed to protect direct percpu ptr access (from map value) and following bpf_this_cpu_ptr() and bpf_per_cpu_ptr() helpers. Signed-off-by: Yonghong Song Link: https://lore.kernel.org/r/20230827152811.2000125-1-yonghong.song@linux.dev Signed-off-by: Alexei Starovoitov