bpf: fix build warnings and add function read_trace_pipe() (5ed3ccbd) · Commits · 戴 / test

There are two improvements in this patch: 1. Fix the build warnings; 2. Add function read_trace_pipe() to print the result on the screen; Before this patch, we can get the result through /sys/kernel/de bug/tracing/trace_pipe and get nothing on the screen. By applying this patch, the result can be printed on the screen. $ ./tracex6 ... tracex6-705 [003] d..1 131.428593: : CPU-3 19981414 sshd-683 [000] d..1 131.428727: : CPU-0 221682321 sshd-683 [000] d..1 131.428821: : CPU-0 221808766 sshd-683 [000] d..1 131.428950: : CPU-0 221982984 sshd-683 [000] d..1 131.429045: : CPU-0 222111851 tracex6-705 [003] d..1 131.429168: : CPU-3 20757551 sshd-683 [000] d..1 131.429170: : CPU-0 222281240 sshd-683 [000] d..1 131.429261: : CPU-0 222403340 sshd-683 [000] d..1 131.429378: : CPU-0 222561024 ... Signed-off-by:

Kaixu Xia <xiakaixu@huawei.com> Acked-by:

Alexei Starovoitov <ast@plumgrid.com> Signed-off-by:

David S. Miller <davem@davemloft.net>

samples/bpf/tracex6_kern.c

+1 −0

Original line number	Diff line number	Diff line
		#include <linux/ptrace.h>
		#include <linux/version.h>
		#include <uapi/linux/bpf.h>
		#include "bpf_helpers.h"

samples/bpf/tracex6_user.c

+13 −9

Original line number	Diff line number	Diff line
		@@ -17,8 +17,7 @@ static void test_bpf_perf_event(void)
		{
		int nr_cpus = sysconf(_SC_NPROCESSORS_CONF);
		int pmu_fd = malloc(nr_cpus sizeof(int));
		unsigned long value;
		int i;
		int status, i;

		struct perf_event_attr attr_insn_pmu = {
		.freq = 0,
		@@ -32,22 +31,26 @@ static void test_bpf_perf_event(void)

		for (i = 0; i < nr_cpus; i++) {
		pmu_fd[i] = perf_event_open(&attr_insn_pmu, -1/pid/, i/cpu/, -1/group_fd/, 0);
		if (pmu_fd[i] < 0)
		if (pmu_fd[i] < 0) {
		printf("event syscall failed\n");
		goto exit;
		}

		bpf_update_elem(map_fd[0], &i, &pmu_fd[i], BPF_ANY);
		ioctl(pmu_fd[i], PERF_EVENT_IOC_ENABLE, 0);
		}

		system("ls");
		system("pwd");
		system("sleep 2");
		status = system("ls > /dev/null");
		if (status)
		goto exit;
		status = system("sleep 2");
		if (status)
		goto exit;

		exit:
		for (i = 0; i < nr_cpus; i++)
		close(pmu_fd[i]);

		close(map_fd);

		close(map_fd[0]);
		free(pmu_fd);
		}

		@@ -63,6 +66,7 @@ int main(int argc, char **argv)
		}

		test_bpf_perf_event();
		read_trace_pipe();

		return 0;
		}

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