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// 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";
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