Linux kernel mirror (for testing)
git.kernel.org/pub/scm/linux/kernel/git/torvalds/linux.git
tjh.dev
kernel
os
linux
1// SPDX-License-Identifier: GPL-2.0
2#include <test_progs.h>
3
4void test_stacktrace_map(void)
5{
6 int control_map_fd, stackid_hmap_fd, stackmap_fd, stack_amap_fd;
7 const char *file = "./test_stacktrace_map.o";
8 int bytes, efd, err, pmu_fd, prog_fd, stack_trace_len;
9 struct perf_event_attr attr = {};
10 __u32 key, val, duration = 0;
11 struct bpf_object *obj;
12 char buf[256];
13
14 err = bpf_prog_load(file, BPF_PROG_TYPE_TRACEPOINT, &obj, &prog_fd);
15 if (CHECK(err, "prog_load", "err %d errno %d\n", err, errno))
16 return;
17
18 /* Get the ID for the sched/sched_switch tracepoint */
19 snprintf(buf, sizeof(buf),
20 "/sys/kernel/debug/tracing/events/sched/sched_switch/id");
21 efd = open(buf, O_RDONLY, 0);
22 if (CHECK(efd < 0, "open", "err %d errno %d\n", efd, errno))
23 goto close_prog;
24
25 bytes = read(efd, buf, sizeof(buf));
26 close(efd);
27 if (bytes <= 0 || bytes >= sizeof(buf))
28 goto close_prog;
29
30 /* Open the perf event and attach bpf progrram */
31 attr.config = strtol(buf, NULL, 0);
32 attr.type = PERF_TYPE_TRACEPOINT;
33 attr.sample_type = PERF_SAMPLE_RAW | PERF_SAMPLE_CALLCHAIN;
34 attr.sample_period = 1;
35 attr.wakeup_events = 1;
36 pmu_fd = syscall(__NR_perf_event_open, &attr, -1 /* pid */,
37 0 /* cpu 0 */, -1 /* group id */,
38 0 /* flags */);
39 if (CHECK(pmu_fd < 0, "perf_event_open", "err %d errno %d\n",
40 pmu_fd, errno))
41 goto close_prog;
42
43 err = ioctl(pmu_fd, PERF_EVENT_IOC_ENABLE, 0);
44 if (err)
45 goto disable_pmu;
46
47 err = ioctl(pmu_fd, PERF_EVENT_IOC_SET_BPF, prog_fd);
48 if (err)
49 goto disable_pmu;
50
51 /* find map fds */
52 control_map_fd = bpf_find_map(__func__, obj, "control_map");
53 if (control_map_fd < 0)
54 goto disable_pmu;
55
56 stackid_hmap_fd = bpf_find_map(__func__, obj, "stackid_hmap");
57 if (stackid_hmap_fd < 0)
58 goto disable_pmu;
59
60 stackmap_fd = bpf_find_map(__func__, obj, "stackmap");
61 if (stackmap_fd < 0)
62 goto disable_pmu;
63
64 stack_amap_fd = bpf_find_map(__func__, obj, "stack_amap");
65 if (stack_amap_fd < 0)
66 goto disable_pmu;
67
68 /* give some time for bpf program run */
69 sleep(1);
70
71 /* disable stack trace collection */
72 key = 0;
73 val = 1;
74 bpf_map_update_elem(control_map_fd, &key, &val, 0);
75
76 /* for every element in stackid_hmap, we can find a corresponding one
77 * in stackmap, and vise versa.
78 */
79 err = compare_map_keys(stackid_hmap_fd, stackmap_fd);
80 if (CHECK(err, "compare_map_keys stackid_hmap vs. stackmap",
81 "err %d errno %d\n", err, errno))
82 goto disable_pmu_noerr;
83
84 err = compare_map_keys(stackmap_fd, stackid_hmap_fd);
85 if (CHECK(err, "compare_map_keys stackmap vs. stackid_hmap",
86 "err %d errno %d\n", err, errno))
87 goto disable_pmu_noerr;
88
89 stack_trace_len = PERF_MAX_STACK_DEPTH * sizeof(__u64);
90 err = compare_stack_ips(stackmap_fd, stack_amap_fd, stack_trace_len);
91 if (CHECK(err, "compare_stack_ips stackmap vs. stack_amap",
92 "err %d errno %d\n", err, errno))
93 goto disable_pmu_noerr;
94
95 goto disable_pmu_noerr;
96disable_pmu:
97 error_cnt++;
98disable_pmu_noerr:
99 ioctl(pmu_fd, PERF_EVENT_IOC_DISABLE);
100 close(pmu_fd);
101close_prog:
102 bpf_object__close(obj);
103}