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