69 lines · c
1// SPDX-License-Identifier: GPL-2.02#include <vmlinux.h>3#include <bpf/bpf_helpers.h>4 5#define TEST_STACK_DEPTH 26#define TEST_MAX_ENTRIES 163847 8typedef __u64 stack_trace_t[TEST_STACK_DEPTH];9 10struct {11 __uint(type, BPF_MAP_TYPE_STACK_TRACE);12 __uint(max_entries, TEST_MAX_ENTRIES);13 __type(key, __u32);14 __type(value, stack_trace_t);15} stackmap SEC(".maps");16 17struct {18 __uint(type, BPF_MAP_TYPE_HASH);19 __uint(max_entries, TEST_MAX_ENTRIES);20 __type(key, __u32);21 __type(value, __u32);22} stackid_hmap SEC(".maps");23 24struct {25 __uint(type, BPF_MAP_TYPE_ARRAY);26 __uint(max_entries, TEST_MAX_ENTRIES);27 __type(key, __u32);28 __type(value, stack_trace_t);29} stack_amap SEC(".maps");30 31int pid = 0;32int control = 0;33int failed = 0;34 35SEC("tracepoint/sched/sched_switch")36int oncpu(struct trace_event_raw_sched_switch *ctx)37{38 __u32 max_len = TEST_STACK_DEPTH * sizeof(__u64);39 __u32 key = 0, val = 0;40 __u64 *stack_p;41 42 if (pid != (bpf_get_current_pid_tgid() >> 32))43 return 0;44 45 if (control)46 return 0;47 48 /* it should allow skipping whole buffer size entries */49 key = bpf_get_stackid(ctx, &stackmap, TEST_STACK_DEPTH);50 if ((int)key >= 0) {51 /* The size of stackmap and stack_amap should be the same */52 bpf_map_update_elem(&stackid_hmap, &key, &val, 0);53 stack_p = bpf_map_lookup_elem(&stack_amap, &key);54 if (stack_p) {55 bpf_get_stack(ctx, stack_p, max_len, TEST_STACK_DEPTH);56 /* it wrongly skipped all the entries and filled zero */57 if (stack_p[0] == 0)58 failed = 1;59 }60 } else {61 /* old kernel doesn't support skipping that many entries */62 failed = 2;63 }64 65 return 0;66}67 68char _license[] SEC("license") = "GPL";69