// SPDX-License-Identifier: GPL-2.0 #include <vmlinux.h> #include <bpf/bpf_helpers.h> #define TEST_STACK_DEPTH 2 #define TEST_MAX_ENTRIES 16384 typedef __u64 stack_trace_t[TEST_STACK_DEPTH]; struct { __uint(type, BPF_MAP_TYPE_STACK_TRACE); __uint(max_entries, TEST_MAX_ENTRIES); __type(key, __u32); __type(value, stack_trace_t); } stackmap SEC(".maps"); struct { __uint(type, BPF_MAP_TYPE_HASH); __uint(max_entries, TEST_MAX_ENTRIES); __type(key, __u32); __type(value, __u32); } stackid_hmap SEC(".maps"); struct { __uint(type, BPF_MAP_TYPE_ARRAY); __uint(max_entries, TEST_MAX_ENTRIES); __type(key, __u32); __type(value, stack_trace_t); } stack_amap SEC(".maps"); int pid = 0; int control = 0; int failed = 0; SEC("tracepoint/sched/sched_switch") int oncpu(struct trace_event_raw_sched_switch *ctx) { __u32 max_len = TEST_STACK_DEPTH * sizeof(__u64); __u32 key = 0, val = 0; __u64 *stack_p; if (pid != (bpf_get_current_pid_tgid() >> 32)) return 0; if (control) return 0; /* it should allow skipping whole buffer size entries */ key = bpf_get_stackid(ctx, &stackmap, TEST_STACK_DEPTH); if ((int)key >= 0) { /* The size of stackmap and stack_amap should be the same */ bpf_map_update_elem(&stackid_hmap, &key, &val, 0); stack_p = bpf_map_lookup_elem(&stack_amap, &key); if (stack_p) { bpf_get_stack(ctx, stack_p, max_len, TEST_STACK_DEPTH); /* it wrongly skipped all the entries and filled zero */ if (stack_p[0] == 0) failed = 1; } } else { /* old kernel doesn't support skipping that many entries */ failed = 2; } return 0; } char _license[] SEC("license") = "GPL";