From 3ced9b600234e6bb13cb25654ce44c4896485cf2 Mon Sep 17 00:00:00 2001 From: Yonghong Song Date: Thu, 4 Jan 2018 13:55:04 -0800 Subject: [PATCH] tools/bpf: add a bpf selftest for stacktrace Added a bpf selftest in test_progs at tools directory for stacktrace. The test will populate a hashtable map and a stacktrace map at the same time with the same key, stackid. The user space will compare both maps, using BPF_MAP_LOOKUP_ELEM command and BPF_MAP_GET_NEXT_KEY command, to ensure that both have the same set of keys. Signed-off-by: Yonghong Song Signed-off-by: Daniel Borkmann --- tools/testing/selftests/bpf/Makefile | 2 +- tools/testing/selftests/bpf/test_progs.c | 127 ++++++++++++++++++++++ tools/testing/selftests/bpf/test_stacktrace_map.c | 62 +++++++++++ 3 files changed, 190 insertions(+), 1 deletion(-) create mode 100644 tools/testing/selftests/bpf/test_stacktrace_map.c diff --git a/tools/testing/selftests/bpf/Makefile b/tools/testing/selftests/bpf/Makefile index 1304753..a8aa7e2 100644 --- a/tools/testing/selftests/bpf/Makefile +++ b/tools/testing/selftests/bpf/Makefile @@ -19,7 +19,7 @@ TEST_GEN_PROGS = test_verifier test_tag test_maps test_lru_map test_lpm_map test TEST_GEN_FILES = test_pkt_access.o test_xdp.o test_l4lb.o test_tcp_estats.o test_obj_id.o \ test_pkt_md_access.o test_xdp_redirect.o test_xdp_meta.o sockmap_parse_prog.o \ sockmap_verdict_prog.o dev_cgroup.o sample_ret0.o test_tracepoint.o \ - test_l4lb_noinline.o test_xdp_noinline.o + test_l4lb_noinline.o test_xdp_noinline.o test_stacktrace_map.o TEST_PROGS := test_kmod.sh test_xdp_redirect.sh test_xdp_meta.sh \ test_offload.py diff --git a/tools/testing/selftests/bpf/test_progs.c b/tools/testing/selftests/bpf/test_progs.c index 09087ab..b549308 100644 --- a/tools/testing/selftests/bpf/test_progs.c +++ b/tools/testing/selftests/bpf/test_progs.c @@ -837,6 +837,132 @@ static void test_tp_attach_query(void) free(query); } +static int compare_map_keys(int map1_fd, int map2_fd) +{ + __u32 key, next_key; + char val_buf[PERF_MAX_STACK_DEPTH * sizeof(__u64)]; + int err; + + err = bpf_map_get_next_key(map1_fd, NULL, &key); + if (err) + return err; + err = bpf_map_lookup_elem(map2_fd, &key, val_buf); + if (err) + return err; + + while (bpf_map_get_next_key(map1_fd, &key, &next_key) == 0) { + err = bpf_map_lookup_elem(map2_fd, &next_key, val_buf); + if (err) + return err; + + key = next_key; + } + if (errno != ENOENT) + return -1; + + return 0; +} + +static void test_stacktrace_map() +{ + int control_map_fd, stackid_hmap_fd, stackmap_fd; + const char *file = "./test_stacktrace_map.o"; + int bytes, efd, err, pmu_fd, prog_fd; + struct perf_event_attr attr = {}; + __u32 key, val, duration = 0; + struct bpf_object *obj; + char buf[256]; + + err = bpf_prog_load(file, BPF_PROG_TYPE_TRACEPOINT, &obj, &prog_fd); + if (CHECK(err, "prog_load", "err %d errno %d\n", err, errno)) + goto out; + + /* Get the ID for the sched/sched_switch tracepoint */ + snprintf(buf, sizeof(buf), + "/sys/kernel/debug/tracing/events/sched/sched_switch/id"); + efd = open(buf, O_RDONLY, 0); + if (CHECK(efd < 0, "open", "err %d errno %d\n", efd, errno)) + goto close_prog; + + bytes = read(efd, buf, sizeof(buf)); + close(efd); + if (CHECK(bytes <= 0 || bytes >= sizeof(buf), + "read", "bytes %d errno %d\n", bytes, errno)) + goto close_prog; + + /* Open the perf event and attach bpf progrram */ + attr.config = strtol(buf, NULL, 0); + attr.type = PERF_TYPE_TRACEPOINT; + attr.sample_type = PERF_SAMPLE_RAW | PERF_SAMPLE_CALLCHAIN; + attr.sample_period = 1; + attr.wakeup_events = 1; + pmu_fd = syscall(__NR_perf_event_open, &attr, -1 /* pid */, + 0 /* cpu 0 */, -1 /* group id */, + 0 /* flags */); + if (CHECK(pmu_fd < 0, "perf_event_open", "err %d errno %d\n", + pmu_fd, errno)) + goto close_prog; + + err = ioctl(pmu_fd, PERF_EVENT_IOC_ENABLE, 0); + if (CHECK(err, "perf_event_ioc_enable", "err %d errno %d\n", + err, errno)) + goto close_pmu; + + err = ioctl(pmu_fd, PERF_EVENT_IOC_SET_BPF, prog_fd); + if (CHECK(err, "perf_event_ioc_set_bpf", "err %d errno %d\n", + err, errno)) + goto disable_pmu; + + /* find map fds */ + control_map_fd = bpf_find_map(__func__, obj, "control_map"); + if (CHECK(control_map_fd < 0, "bpf_find_map control_map", + "err %d errno %d\n", err, errno)) + goto disable_pmu; + + stackid_hmap_fd = bpf_find_map(__func__, obj, "stackid_hmap"); + if (CHECK(stackid_hmap_fd < 0, "bpf_find_map stackid_hmap", + "err %d errno %d\n", err, errno)) + goto disable_pmu; + + stackmap_fd = bpf_find_map(__func__, obj, "stackmap"); + if (CHECK(stackmap_fd < 0, "bpf_find_map stackmap", "err %d errno %d\n", + err, errno)) + goto disable_pmu; + + /* give some time for bpf program run */ + sleep(1); + + /* disable stack trace collection */ + key = 0; + val = 1; + bpf_map_update_elem(control_map_fd, &key, &val, 0); + + /* for every element in stackid_hmap, we can find a corresponding one + * in stackmap, and vise versa. + */ + err = compare_map_keys(stackid_hmap_fd, stackmap_fd); + if (CHECK(err, "compare_map_keys stackid_hmap vs. stackmap", + "err %d errno %d\n", err, errno)) + goto disable_pmu; + + err = compare_map_keys(stackmap_fd, stackid_hmap_fd); + if (CHECK(err, "compare_map_keys stackmap vs. stackid_hmap", + "err %d errno %d\n", err, errno)) + ; /* fall through */ + +disable_pmu: + ioctl(pmu_fd, PERF_EVENT_IOC_DISABLE); + +close_pmu: + close(pmu_fd); + +close_prog: + bpf_object__close(obj); + +out: + return; +} + int main(void) { struct rlimit rinf = { RLIM_INFINITY, RLIM_INFINITY }; @@ -852,6 +978,7 @@ int main(void) test_pkt_md_access(); test_obj_name(); test_tp_attach_query(); + test_stacktrace_map(); printf("Summary: %d PASSED, %d FAILED\n", pass_cnt, error_cnt); return error_cnt ? EXIT_FAILURE : EXIT_SUCCESS; diff --git a/tools/testing/selftests/bpf/test_stacktrace_map.c b/tools/testing/selftests/bpf/test_stacktrace_map.c new file mode 100644 index 0000000..76d85c5d --- /dev/null +++ b/tools/testing/selftests/bpf/test_stacktrace_map.c @@ -0,0 +1,62 @@ +// SPDX-License-Identifier: GPL-2.0 +// Copyright (c) 2018 Facebook + +#include +#include "bpf_helpers.h" + +#ifndef PERF_MAX_STACK_DEPTH +#define PERF_MAX_STACK_DEPTH 127 +#endif + +struct bpf_map_def SEC("maps") control_map = { + .type = BPF_MAP_TYPE_ARRAY, + .key_size = sizeof(__u32), + .value_size = sizeof(__u32), + .max_entries = 1, +}; + +struct bpf_map_def SEC("maps") stackid_hmap = { + .type = BPF_MAP_TYPE_HASH, + .key_size = sizeof(__u32), + .value_size = sizeof(__u32), + .max_entries = 10000, +}; + +struct bpf_map_def SEC("maps") stackmap = { + .type = BPF_MAP_TYPE_STACK_TRACE, + .key_size = sizeof(__u32), + .value_size = sizeof(__u64) * PERF_MAX_STACK_DEPTH, + .max_entries = 10000, +}; + +/* taken from /sys/kernel/debug/tracing/events/sched/sched_switch/format */ +struct sched_switch_args { + unsigned long long pad; + char prev_comm[16]; + int prev_pid; + int prev_prio; + long long prev_state; + char next_comm[16]; + int next_pid; + int next_prio; +}; + +SEC("tracepoint/sched/sched_switch") +int oncpu(struct sched_switch_args *ctx) +{ + __u32 key = 0, val = 0, *value_p; + + value_p = bpf_map_lookup_elem(&control_map, &key); + if (value_p && *value_p) + return 0; /* skip if non-zero *value_p */ + + /* The size of stackmap and stackid_hmap should be the same */ + key = bpf_get_stackid(ctx, &stackmap, 0); + if ((int)key >= 0) + bpf_map_update_elem(&stackid_hmap, &key, &val, 0); + + return 0; +} + +char _license[] SEC("license") = "GPL"; +__u32 _version SEC("version") = 1; /* ignored by tracepoints, required by libbpf.a */ -- 2.7.4