cregit-Linux how code gets into the kernel

Release 4.9 samples/bpf/trace_event_kern.c

Directory: samples/bpf
/* Copyright (c) 2016 Facebook
 *
 * This program is free software; you can redistribute it and/or
 * modify it under the terms of version 2 of the GNU General Public
 * License as published by the Free Software Foundation.
 */
#include <linux/ptrace.h>
#include <linux/version.h>
#include <uapi/linux/bpf.h>
#include <uapi/linux/bpf_perf_event.h>
#include <uapi/linux/perf_event.h>
#include "bpf_helpers.h"


struct key_t {
	
char comm[TASK_COMM_LEN];
	
u32 kernstack;
	
u32 userstack;
};

struct bpf_map_def SEC("maps") counts = {
	.type = BPF_MAP_TYPE_HASH,
	.key_size = sizeof(struct key_t),
	.value_size = sizeof(u64),
	.max_entries = 10000,
};

struct bpf_map_def SEC("maps") stackmap = {
	.type = BPF_MAP_TYPE_STACK_TRACE,
	.key_size = sizeof(u32),
	.value_size = PERF_MAX_STACK_DEPTH * sizeof(u64),
	.max_entries = 10000,
};


#define KERN_STACKID_FLAGS (0 | BPF_F_FAST_STACK_CMP)

#define USER_STACKID_FLAGS (0 | BPF_F_FAST_STACK_CMP | BPF_F_USER_STACK)

SEC("perf_event")

int bpf_prog1(struct bpf_perf_event_data *ctx) { char fmt[] = "CPU-%d period %lld ip %llx"; u32 cpu = bpf_get_smp_processor_id(); struct key_t key; u64 *val, one = 1; if (ctx->sample_period < 10000) /* ignore warmup */ return 0; bpf_get_current_comm(&key.comm, sizeof(key.comm)); key.kernstack = bpf_get_stackid(ctx, &stackmap, KERN_STACKID_FLAGS); key.userstack = bpf_get_stackid(ctx, &stackmap, USER_STACKID_FLAGS); if ((int)key.kernstack < 0 && (int)key.userstack < 0) { bpf_trace_printk(fmt, sizeof(fmt), cpu, ctx->sample_period, PT_REGS_IP(&ctx->regs)); return 0; } val = bpf_map_lookup_elem(&counts, &key); if (val) (*val)++; else bpf_map_update_elem(&counts, &key, &one, BPF_NOEXIST); return 0; }

Contributors

PersonTokensPropCommitsCommitProp
alexei starovoitovalexei starovoitov17397.74%150.00%
michael holzheumichael holzheu42.26%150.00%
Total177100.00%2100.00%

char _license[] SEC("license") = "GPL";

Overall Contributors

PersonTokensPropCommitsCommitProp
alexei starovoitovalexei starovoitov30698.71%150.00%
michael holzheumichael holzheu41.29%150.00%
Total310100.00%2100.00%
Directory: samples/bpf