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Message-ID: <6b25ed31-d47e-eaaf-6a10-801ea2e19c79@fb.com>
Date: Thu, 23 May 2019 05:50:30 +0000
From: Yonghong Song <yhs@...com>
To: Andrii Nakryiko <andrii.nakryiko@...il.com>
CC: "bpf@...r.kernel.org" <bpf@...r.kernel.org>,
Networking <netdev@...r.kernel.org>,
Alexei Starovoitov <ast@...com>,
Daniel Borkmann <daniel@...earbox.net>,
Kernel Team <Kernel-team@...com>,
Peter Zijlstra <peterz@...radead.org>
Subject: Re: [PATCH bpf-next v3 3/3] tools/bpf: add selftest in test_progs for
bpf_send_signal() helper
On 5/22/19 8:47 PM, Andrii Nakryiko wrote:
> On Wed, May 22, 2019 at 4:16 PM Yonghong Song <yhs@...com> wrote:
>>
>> The test covered both nmi and tracepoint perf events.
>> $ ./test_progs
>> ...
>> test_send_signal_tracepoint:PASS:tracepoint 0 nsec
>> ...
>> test_send_signal_common:PASS:tracepoint 0 nsec
>> ...
>> test_send_signal_common:PASS:perf_event 0 nsec
>> ...
>> test_send_signal:OK
>>
>> Signed-off-by: Yonghong Song <yhs@...com>
>> ---
>
> Looks good to me, just minor nits below.
>
> Acked-by: Andrii Nakryiko <andriin@...com>
>
>> tools/testing/selftests/bpf/bpf_helpers.h | 1 +
>> .../selftests/bpf/prog_tests/send_signal.c | 193 ++++++++++++++++++
>> .../bpf/progs/test_send_signal_kern.c | 51 +++++
>> 3 files changed, 245 insertions(+)
>> create mode 100644 tools/testing/selftests/bpf/prog_tests/send_signal.c
>> create mode 100644 tools/testing/selftests/bpf/progs/test_send_signal_kern.c
>>
>> diff --git a/tools/testing/selftests/bpf/bpf_helpers.h b/tools/testing/selftests/bpf/bpf_helpers.h
>> index 5f6f9e7aba2a..cb02521b8e58 100644
>> --- a/tools/testing/selftests/bpf/bpf_helpers.h
>> +++ b/tools/testing/selftests/bpf/bpf_helpers.h
>> @@ -216,6 +216,7 @@ static void *(*bpf_sk_storage_get)(void *map, struct bpf_sock *sk,
>> (void *) BPF_FUNC_sk_storage_get;
>> static int (*bpf_sk_storage_delete)(void *map, struct bpf_sock *sk) =
>> (void *)BPF_FUNC_sk_storage_delete;
>> +static int (*bpf_send_signal)(unsigned sig) = (void *)BPF_FUNC_send_signal;
>>
>> /* llvm builtin functions that eBPF C program may use to
>> * emit BPF_LD_ABS and BPF_LD_IND instructions
>> diff --git a/tools/testing/selftests/bpf/prog_tests/send_signal.c b/tools/testing/selftests/bpf/prog_tests/send_signal.c
>> new file mode 100644
>> index 000000000000..ff2cabd3d8c4
>> --- /dev/null
>> +++ b/tools/testing/selftests/bpf/prog_tests/send_signal.c
>> @@ -0,0 +1,193 @@
>> +// SPDX-License-Identifier: GPL-2.0
>> +#include <test_progs.h>
>> +
>> +static volatile int sigusr1_received = 0;
>> +
>> +static void sigusr1_handler(int signum)
>> +{
>> + sigusr1_received++;
>> +}
>> +
>> +static int test_send_signal_common(struct perf_event_attr *attr,
>> + int prog_type,
>> + const char *test_name)
>> +{
>> + int err = -1, pmu_fd, prog_fd, info_map_fd, status_map_fd;
>> + const char *file = "./test_send_signal_kern.o";
>> + struct bpf_object *obj = NULL;
>> + int pipe_c2p[2], pipe_p2c[2];
>> + __u32 key = 0, duration = 0;
>> + char buf[256];
>> + pid_t pid;
>> + __u64 val;
>> +
>> + if (CHECK(pipe(pipe_c2p), test_name,
>> + "pipe pipe_c2p error: %s\n", strerror(errno)))
>> + goto no_fork_done;
>> +
>> + if (CHECK(pipe(pipe_p2c), test_name,
>> + "pipe pipe_p2c error: %s\n", strerror(errno))) {
>> + close(pipe_c2p[0]);
>> + close(pipe_c2p[1]);
>> + goto no_fork_done;
>> + }
>> +
>> + pid = fork();
>> + if (CHECK(pid < 0, test_name, "fork error: %s\n", strerror(errno))) {
>> + close(pipe_c2p[0]);
>> + close(pipe_c2p[1]);
>> + close(pipe_p2c[0]);
>> + close(pipe_p2c[1]);
>> + goto no_fork_done;
>> + }
>> +
>> + if (pid == 0) {
>> + /* install signal handler and notify parent */
>> + signal(SIGUSR1, sigusr1_handler);
>> +
>> + close(pipe_c2p[0]); /* close read */
>> + close(pipe_p2c[1]); /* close write */
>> +
>> + /* notify parent signal handler is installed */
>> + write(pipe_c2p[1], buf, 1);
>> +
>> + /* make sense parent enabled bpf program to send_signal */
>
> typo? sense => sure?
right. typo. will fix.
>
>> + read(pipe_p2c[0], buf, 1);
>> +
>> + /* wait a little for signal handler */
>> + sleep(1);
>> +
>> + if (sigusr1_received)
>> + write(pipe_c2p[1], "2", 1);
>> + else
>> + write(pipe_c2p[1], "0", 1);
>> +
>> + /* wait for parent notification and exit */
>> + read(pipe_p2c[0], buf, 1);
>> +
>> + close(pipe_c2p[1]);
>> + close(pipe_p2c[0]);
>> + exit(0);
>> + }
>> +
>> + close(pipe_c2p[1]); /* close write */
>> + close(pipe_p2c[0]); /* close read */
>> +
>> + err = bpf_prog_load(file, prog_type, &obj, &prog_fd);
>> + if (CHECK(err < 0, test_name, "bpf_prog_load error: %s\n",
>> + strerror(errno)))
>> + goto prog_load_failure;
>> +
>> + pmu_fd = syscall(__NR_perf_event_open, attr, pid, -1,
>> + -1 /* group id */, 0 /* flags */);
>> + if (CHECK(pmu_fd < 0, test_name, "perf_event_open error: %s\n",
>> + strerror(errno))) {
>> + err = -1;
>> + goto close_prog;
>> + }
>> +
>> + err = ioctl(pmu_fd, PERF_EVENT_IOC_ENABLE, 0);
>> + if (CHECK(err < 0, test_name, "ioctl perf_event_ioc_enable error: %s\n",
>> + strerror(errno)))
>> + goto disable_pmu;
>> +
>> + err = ioctl(pmu_fd, PERF_EVENT_IOC_SET_BPF, prog_fd);
>> + if (CHECK(err < 0, test_name, "ioctl perf_event_ioc_set_bpf error: %s\n",
>> + strerror(errno)))
>> + goto disable_pmu;
>> +
>> + err = -1;
>> + info_map_fd = bpf_object__find_map_fd_by_name(obj, "info_map");
>> + if (CHECK(info_map_fd < 0, test_name, "find map %s error\n", "info_map"))
>> + goto disable_pmu;
>> +
>> + status_map_fd = bpf_object__find_map_fd_by_name(obj, "status_map");
>> + if (CHECK(status_map_fd < 0, test_name, "find map %s error\n", "status_map"))
>> + goto disable_pmu;
>> +
>> + /* wait until child signal handler installed */
>> + read(pipe_c2p[0], buf, 1);
>> +
>> + /* trigger the bpf send_signal */
>> + key = 0;
>> + val = (((__u64)(SIGUSR1)) << 32) | pid;
>> + bpf_map_update_elem(info_map_fd, &key, &val, 0);
>> +
>> + /* notify child that bpf program can send_signal now */
>> + write(pipe_p2c[1], buf, 1);
>> +
>> + /* wait for result */
>> + read(pipe_c2p[0], buf, 1);
>> +
>> + err = CHECK(buf[0] != '2', test_name, "incorrect result\n");
>> +
>> + /* notify child safe to exit */
>> + write(pipe_p2c[1], buf, 1);
>> +
>> +disable_pmu:
>> + close(pmu_fd);
>> +close_prog:
>> + bpf_object__close(obj);
>> +prog_load_failure:
>> + close(pipe_c2p[0]);
>> + close(pipe_p2c[1]);
>> + wait(NULL);
>> +no_fork_done:
>> + return err;
>> +}
>> +
>> +static int test_send_signal_tracepoint(void)
>> +{
>> + struct perf_event_attr attr = {
>> + .type = PERF_TYPE_TRACEPOINT,
>> + .sample_type = PERF_SAMPLE_RAW | PERF_SAMPLE_CALLCHAIN,
>> + .sample_period = 1,
>> + .wakeup_events = 1,
>> + };
>> + __u32 duration = 0;
>> + int bytes, efd;
>> + char buf[256];
>> +
>> + snprintf(buf, sizeof(buf),
>> + "/sys/kernel/debug/tracing/events/syscalls/sys_enter_nanosleep/id");
>
> You could do it statically:
>
> char buf[256] = "/sys/...../id";
sure, will do this, to make line shorter.
>
>> + efd = open(buf, O_RDONLY, 0);
>> + if (CHECK(efd < 0, "tracepoint",
>> + "open syscalls/sys_enter_nanosleep/id failure: %s\n",
>> + strerror(errno)))
>> + return -1;
>> +
>> + bytes = read(efd, buf, sizeof(buf));
>> + close(efd);
>> + if (CHECK(bytes <= 0 || bytes >= sizeof(buf), "tracepoint",
>> + "read syscalls/sys_enter_nanosleep/id failure: %s\n",
>> + strerror(errno)))
>> + return -1;
>> +
>> + attr.config = strtol(buf, NULL, 0);
>> +
>> + return test_send_signal_common(&attr, BPF_PROG_TYPE_TRACEPOINT, "tracepoint");
>> +}
>> +
>> +static int test_send_signal_nmi(void)
>> +{
>> + struct perf_event_attr attr = {
>> + .sample_freq = 50,
>> + .freq = 1,
>> + .type = PERF_TYPE_HARDWARE,
>> + .config = PERF_COUNT_HW_CPU_CYCLES,
>> + };
>> +
>> + return test_send_signal_common(&attr, BPF_PROG_TYPE_PERF_EVENT, "perf_event");
>> +}
>> +
>> +void test_send_signal(void)
>> +{
>> + int ret = 0;
>> +
>> + ret |= test_send_signal_tracepoint();
>> + ret |= test_send_signal_nmi();
>> + if (!ret)
>> + printf("test_send_signal:OK\n");
>> + else
>> + printf("test_send_signal:FAIL\n");
>> +}
>> diff --git a/tools/testing/selftests/bpf/progs/test_send_signal_kern.c b/tools/testing/selftests/bpf/progs/test_send_signal_kern.c
>> new file mode 100644
>> index 000000000000..45a1a1a2c345
>> --- /dev/null
>> +++ b/tools/testing/selftests/bpf/progs/test_send_signal_kern.c
>> @@ -0,0 +1,51 @@
>> +// SPDX-License-Identifier: GPL-2.0
>> +// Copyright (c) 2019 Facebook
>> +#include <linux/bpf.h>
>> +#include <linux/version.h>
>> +#include "bpf_helpers.h"
>> +
>> +struct bpf_map_def SEC("maps") info_map = {
>> + .type = BPF_MAP_TYPE_ARRAY,
>> + .key_size = sizeof(__u32),
>> + .value_size = sizeof(__u64),
>> + .max_entries = 1,
>> +};
>> +
>> +BPF_ANNOTATE_KV_PAIR(info_map, __u32, __u64);
>> +
>> +struct bpf_map_def SEC("maps") status_map = {
>> + .type = BPF_MAP_TYPE_ARRAY,
>> + .key_size = sizeof(__u32),
>> + .value_size = sizeof(__u64),
>> + .max_entries = 1,
>> +};
>> +
>> +BPF_ANNOTATE_KV_PAIR(status_map, __u32, __u64);
>> +
>> +SEC("send_signal_demo")
>> +int bpf_send_signal_test(void *ctx)
>> +{
>> + __u64 *info_val, *status_val;
>> + __u32 key = 0, pid, sig;
>> + int ret;
>> +
>> + status_val = bpf_map_lookup_elem(&status_map, &key);
>> + if (!status_val || *status_val != 0)
>> + return 0;
>> +
>> + info_val = bpf_map_lookup_elem(&info_map, &key);
>> + if (!info_val || *info_val == 0)
>> + return 0;
>> +
>> + sig = *info_val >> 32;
>> + pid = *info_val & 0xffffFFFF;
>> +
>> + if ((bpf_get_current_pid_tgid() >> 32) == pid) {
>> + ret = bpf_send_signal(sig);
>> + if (ret == 0)
>> + *status_val = 1;
>> + }
>> +
>> + return 0;
>> +}
>> +char __license[] SEC("license") = "GPL";
>> --
>> 2.17.1
>>
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