kernel/linux.git/tools/testing/selftests/bpf/progs/percpu_alloc_array.c, branch linux-7.0.y

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: Remove unnecessary direct read of local percpu kptr

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

For the second argument of bpf_kptr_xchg(), if the reg type contains MEM_ALLOC and MEM_PERCPU, which means a percpu allocation, after bpf_kptr_xchg(), the argument is marked as MEM_RCU and MEM_PERCPU if in rcu critical section. This way, re-reading from the map value is not needed. Remove it from the percpu_alloc_array.c selftest. Without previous kernel change, the test will fail like below: 0: R1=ctx(off=0,imm=0) R10=fp0 ; int BPF_PROG(test_array_map_10, int a) 0: (b4) w1 = 0 ; R1_w=0 ; int i, index = 0; 1: (63) *(u32 *)(r10 -4) = r1 ; R1_w=0 R10=fp0 fp-8=0000???? 2: (bf) r2 = r10 ; R2_w=fp0 R10=fp0 ; 3: (07) r2 += -4 ; R2_w=fp-4 ; e = bpf_map_lookup_elem(&array, &index); 4: (18) r1 = 0xffff88810e771800 ; R1_w=map_ptr(off=0,ks=4,vs=16,imm=0) 6: (85) call bpf_map_lookup_elem#1 ; R0_w=map_value_or_null(id=1,off=0,ks=4,vs=16,imm=0) 7: (bf) r6 = r0 ; R0_w=map_value_or_null(id=1,off=0,ks=4,vs=16,imm=0) R6_w=map_value_or_null(id=1,off=0,ks=4,vs=16,imm=0) ; if (!e) 8: (15) if r6 == 0x0 goto pc+81 ; R6_w=map_value(off=0,ks=4,vs=16,imm=0) ; bpf_rcu_read_lock(); 9: (85) call bpf_rcu_read_lock#87892 ; ; p = e->pc; 10: (bf) r7 = r6 ; R6=map_value(off=0,ks=4,vs=16,imm=0) R7_w=map_value(off=0,ks=4,vs=16,imm=0) 11: (07) r7 += 8 ; R7_w=map_value(off=8,ks=4,vs=16,imm=0) 12: (79) r6 = *(u64 *)(r6 +8) ; R6_w=percpu_rcu_ptr_or_null_val_t(id=2,off=0,imm=0) ; if (!p) { 13: (55) if r6 != 0x0 goto pc+13 ; R6_w=0 ; p = bpf_percpu_obj_new(struct val_t); 14: (18) r1 = 0x12 ; R1_w=18 16: (b7) r2 = 0 ; R2_w=0 17: (85) call bpf_percpu_obj_new_impl#87883 ; R0_w=percpu_ptr_or_null_val_t(id=4,ref_obj_id=4,off=0,imm=0) refs=4 18: (bf) r6 = r0 ; R0=percpu_ptr_or_null_val_t(id=4,ref_obj_id=4,off=0,imm=0) R6=percpu_ptr_or_null_val_t(id=4,ref_obj_id=4,off=0,imm=0) refs=4 ; if (!p) 19: (15) if r6 == 0x0 goto pc+69 ; R6=percpu_ptr_val_t(ref_obj_id=4,off=0,imm=0) refs=4 ; p1 = bpf_kptr_xchg(&e->pc, p); 20: (bf) r1 = r7 ; R1_w=map_value(off=8,ks=4,vs=16,imm=0) R7=map_value(off=8,ks=4,vs=16,imm=0) refs=4 21: (bf) r2 = r6 ; R2_w=percpu_ptr_val_t(ref_obj_id=4,off=0,imm=0) R6=percpu_ptr_val_t(ref_obj_id=4,off=0,imm=0) refs=4 22: (85) call bpf_kptr_xchg#194 ; R0_w=percpu_ptr_or_null_val_t(id=6,ref_obj_id=6,off=0,imm=0) refs=6 ; if (p1) { 23: (15) if r0 == 0x0 goto pc+3 ; R0_w=percpu_ptr_val_t(ref_obj_id=6,off=0,imm=0) refs=6 ; bpf_percpu_obj_drop(p1); 24: (bf) r1 = r0 ; R0_w=percpu_ptr_val_t(ref_obj_id=6,off=0,imm=0) R1_w=percpu_ptr_val_t(ref_obj_id=6,off=0,imm=0) refs=6 25: (b7) r2 = 0 ; R2_w=0 refs=6 26: (85) call bpf_percpu_obj_drop_impl#87882 ; ; v = bpf_this_cpu_ptr(p); 27: (bf) r1 = r6 ; R1_w=scalar(id=7) R6=scalar(id=7) 28: (85) call bpf_this_cpu_ptr#154 R1 type=scalar expected=percpu_ptr_, percpu_rcu_ptr_, percpu_trusted_ptr_ The R1 which gets its value from R6 is a scalar. But before insn 22, R6 is R6=percpu_ptr_val_t(ref_obj_id=4,off=0,imm=0) Its type is changed to a scalar at insn 22 without previous patch. Signed-off-by: Yonghong Song Link: https://lore.kernel.org/r/20230827152821.2001129-1-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