stacktrace_map_skip.c (1633B)
1// SPDX-License-Identifier: GPL-2.0 2#include <vmlinux.h> 3#include <bpf/bpf_helpers.h> 4 5#define TEST_STACK_DEPTH 2 6#define TEST_MAX_ENTRIES 16384 7 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";