Tests that when per-cpu hash map or LRU hash map elements are re-used as a result of a bpf program inserting elements, the element values for the other CPUs than the one executing the BPF code are reset to 0. This validates the fix proposed in: https://lkml.kernel.org/bpf/20201027221324.27894-1-david.verbeiren@xxxxxxxxxxxx/ Change-Id: I38bc7b3744ed40704a7b2cc6efa179fb344c4bee Suggested-by: Andrii Nakryiko <andrii@xxxxxxxxxx> Signed-off-by: David Verbeiren <david.verbeiren@xxxxxxxxxxxx> --- .../selftests/bpf/prog_tests/map_init.c | 204 ++++++++++++++++++ 1 file changed, 204 insertions(+) create mode 100644 tools/testing/selftests/bpf/prog_tests/map_init.c diff --git a/tools/testing/selftests/bpf/prog_tests/map_init.c b/tools/testing/selftests/bpf/prog_tests/map_init.c new file mode 100644 index 000000000000..9640cf925908 --- /dev/null +++ b/tools/testing/selftests/bpf/prog_tests/map_init.c @@ -0,0 +1,204 @@ +// SPDX-License-Identifier: GPL-2.0-only +// Copyright (c) 2020 Tessares SA <http://www.tessares.net> + +#include <test_progs.h> + +#define TEST_VALUE 0x1234 + +static int nr_cpus; +static int duration; +static char bpf_log_buf[BPF_LOG_BUF_SIZE]; + +typedef unsigned long long map_key_t; +typedef unsigned long long map_value_t; +typedef struct { + map_value_t v; /* padding */ +} __bpf_percpu_val_align pcpu_map_value_t; + +/* executes bpf program that updates map with key, value */ +static int bpf_prog_insert_elem(int fd, map_key_t key, map_value_t value) +{ + struct bpf_load_program_attr prog; + struct bpf_insn insns[] = { + BPF_LD_IMM64(BPF_REG_8, key), + BPF_LD_IMM64(BPF_REG_9, value), + + /* update: R1=fd, R2=&key, R3=&value, R4=flags */ + BPF_LD_MAP_FD(BPF_REG_1, fd), + BPF_MOV64_REG(BPF_REG_2, BPF_REG_10), + BPF_ALU64_IMM(BPF_ADD, BPF_REG_2, -8), + BPF_STX_MEM(BPF_DW, BPF_REG_2, BPF_REG_8, 0), + BPF_MOV64_REG(BPF_REG_3, BPF_REG_2), + BPF_ALU64_IMM(BPF_ADD, BPF_REG_3, -8), + BPF_STX_MEM(BPF_DW, BPF_REG_3, BPF_REG_9, 0), + BPF_MOV64_IMM(BPF_REG_4, 0), + BPF_EMIT_CALL(BPF_FUNC_map_update_elem), + + BPF_MOV64_IMM(BPF_REG_0, 0), + BPF_EXIT_INSN(), + }; + char buf[64] = {}; + int pfd, err; + __u32 retval = 0; + + memset(&prog, 0, sizeof(prog)); + prog.prog_type = BPF_PROG_TYPE_SCHED_CLS; + prog.insns = insns; + prog.insns_cnt = ARRAY_SIZE(insns); + prog.license = "GPL"; + + pfd = bpf_load_program_xattr(&prog, bpf_log_buf, BPF_LOG_BUF_SIZE); + if (CHECK(pfd < 0, "bpf_load_program_xattr", "failed: %s\n%s\n", + strerror(errno), bpf_log_buf)) + return -1; + + err = bpf_prog_test_run(pfd, 1, buf, sizeof(buf), NULL, NULL, + &retval, NULL); + if (CHECK(err || retval, "bpf_prog_test_run", + "err=%d retval=%d errno=%d\n", err, retval, errno)) + err = -1; + + close(pfd); + + return err; +} + +static int check_values_one_cpu(pcpu_map_value_t *value, map_value_t expected) +{ + int i, nzCnt = 0; + map_value_t val; + + for (i = 0; i < nr_cpus; i++) { + val = bpf_percpu(value, i); + if (val) { + if (val != expected) { + PRINT_FAIL("Unexpected value (cpu %d): 0x%llx\n", + i, val); + return -1; + } + nzCnt++; + } + } + + if (CHECK(nzCnt != 1, "non-zero-count", + "Map value set for %d CPUs instead of 1!\n", nzCnt)) + return -1; + + return 0; +} + +static int map_setup(int map_type, int max, int num) +{ + pcpu_map_value_t value[nr_cpus]; + int map_fd, i, err; + map_key_t key; + + map_fd = bpf_create_map(map_type, sizeof(key), + sizeof(pcpu_map_value_t), 2, 0); + if (CHECK(map_fd < 0, "bpf_create_map", "failed: %s\n", + strerror(errno))) + return -1; + + for (i = 0; i < nr_cpus; i++) + bpf_percpu(value, i) = 0xdeadbeef; + + for (key = 1; key <= num; key++) { + err = bpf_map_update_elem(map_fd, &key, value, BPF_NOEXIST); + if (CHECK(err, "bpf_map_update_elem", "(key=%llu) failed: %s\n", + key, strerror(errno))) { + close(map_fd); + return -1; + } + } + + return map_fd; +} + +/* Add key=1 elem with values set for all CPUs + * Delete elem key=1 + * Run bpf prog that inserts new key=1 elem with value=0x1234 + * (bpf prog can only set value for current CPU) + * Lookup Key=1 and check value is as expected for all CPUs: + * value set by bpf prog for one CPU, 0 for all others + */ +static void test_pcpu_map_init(void) +{ + pcpu_map_value_t value[nr_cpus]; + int map_fd, err; + map_key_t key; + + /* set up map with 1 element, value filled for all CPUs */ + map_fd = map_setup(BPF_MAP_TYPE_PERCPU_HASH, 2, 1); + if (CHECK(map_fd < 0, "map_setup", "failed\n")) + return; + + /* delete key=1 element so it will later be re-used*/ + key = 1; + err = bpf_map_delete_elem(map_fd, &key); + if (CHECK(err, "bpf_map_delete_elem", "failed: %s\n", strerror(errno))) + goto error_map; + + /* run bpf prog that inserts new elem, re-using the slot just freed */ + err = bpf_prog_insert_elem(map_fd, key, TEST_VALUE); + if (!ASSERT_OK(err, "bpf_prog_insert_elem")) + goto error_map; + + /* check that key=1 was re-created by bpf prog */ + err = bpf_map_lookup_elem(map_fd, &key, value); + if (CHECK(err, "bpf_map_lookup_elem", "failed: %s\n", strerror(errno))) + goto error_map; + + /* and has expected value for just a single CPU, 0 for all others */ + check_values_one_cpu(value, TEST_VALUE); + +error_map: + close(map_fd); +} + +/* Add key=1 and key=2 elems with values set for all CPUs + * Run bpf prog that inserts new key=3 elem + * (only for current cpu; other cpus should have initial value = 0) + * Lookup Key=1 and check value is as expected for all CPUs + */ +static void test_pcpu_lru_map_init(void) +{ + pcpu_map_value_t value[nr_cpus]; + int map_fd, err; + map_key_t key; + + /* Set up LRU map with 2 elements, values filled for all CPUs. + * With these 2 elements, the LRU map is full + */ + map_fd = map_setup(BPF_MAP_TYPE_LRU_PERCPU_HASH, 2, 2); + if (CHECK(map_fd < 0, "map_setup", "failed\n")) + return; + + /* run bpf prog that inserts new key=3 element, re-using LRU slot */ + key = 3; + err = bpf_prog_insert_elem(map_fd, key, TEST_VALUE); + if (!ASSERT_OK(err, "bpf_prog_insert_elem")) + goto error_map; + + /* check that key=3 present */ + err = bpf_map_lookup_elem(map_fd, &key, value); + if (CHECK(err, "bpf_map_lookup_elem", "failed: %s\n", strerror(errno))) + goto error_map; + + /* and has expected value for just a single CPU, 0 for all others */ + check_values_one_cpu(value, TEST_VALUE); + +error_map: + close(map_fd); +} + +void test_map_init(void) +{ + nr_cpus = bpf_num_possible_cpus(); + if (CHECK(nr_cpus <= 1, "nr_cpus", "> 1 needed for this test")) + return; + + if (test__start_subtest("pcpu_map_init")) + test_pcpu_map_init(); + if (test__start_subtest("pcpu_lru_map_init")) + test_pcpu_lru_map_init(); +} -- 2.29.0
