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tools/bpf: Add self tests for bpf_send_signal_thread()
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The test_progs send_signal() is amended to test
bpf_send_signal_thread() as well.

   $ ./test_progs -n 40
   #40/1 send_signal_tracepoint:OK
   #40/2 send_signal_perf:OK
   #40/3 send_signal_nmi:OK
   #40/4 send_signal_tracepoint_thread:OK
   #40/5 send_signal_perf_thread:OK
   #40/6 send_signal_nmi_thread:OK
   #40 send_signal:OK
   Summary: 1/6 PASSED, 0 SKIPPED, 0 FAILED

Also took this opportunity to rewrite the send_signal test
using skeleton framework and array mmap to make code
simpler and more readable.

Signed-off-by: Yonghong Song <yhs@fb.com>
Signed-off-by: Alexei Starovoitov <ast@kernel.org>
Link: https://lore.kernel.org/bpf/20200115035003.602425-1-yhs@fb.com
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@yonghong-song
yonghong-song authored and Alexei Starovoitov committed Jan 15, 2020
1 parent 8482941 commit ab8b7f0
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Showing 2 changed files with 73 additions and 106 deletions.
128 changes: 51 additions & 77 deletions tools/testing/selftests/bpf/prog_tests/send_signal.c
View file
Original file line number Diff line number Diff line change
@@ -1,5 +1,6 @@
// SPDX-License-Identifier: GPL-2.0
#include <test_progs.h>
#include "test_send_signal_kern.skel.h"

static volatile int sigusr1_received = 0;

Expand All @@ -9,17 +10,15 @@ static void sigusr1_handler(int signum)
}

static void test_send_signal_common(struct perf_event_attr *attr,
int prog_type,
bool signal_thread,
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;
struct test_send_signal_kern *skel;
int pipe_c2p[2], pipe_p2c[2];
__u32 key = 0, duration = 0;
int err = -1, pmu_fd = -1;
__u32 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)))
Expand Down Expand Up @@ -73,45 +72,42 @@ static void test_send_signal_common(struct perf_event_attr *attr,
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;
skel = test_send_signal_kern__open_and_load();
if (CHECK(!skel, "skel_open_and_load", "skeleton open_and_load failed\n"))
goto skel_open_load_failure;

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;
/* add a delay for child thread to ramp up */
usleep(100);

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;
if (!attr) {
err = test_send_signal_kern__attach(skel);
if (CHECK(err, "skel_attach", "skeleton attach failed\n")) {
err = -1;
goto destroy_skel;
}
} else {
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 destroy_skel;
}

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;
skel->links.send_signal_perf =
bpf_program__attach_perf_event(skel->progs.send_signal_perf, pmu_fd);
if (CHECK(IS_ERR(skel->links.send_signal_perf), "attach_perf_event",
"err %ld\n", PTR_ERR(skel->links.send_signal_perf)))
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);
skel->bss->pid = pid;
skel->bss->sig = SIGUSR1;
skel->bss->signal_thread = signal_thread;

/* notify child that bpf program can send_signal now */
write(pipe_p2c[1], buf, 1);
Expand All @@ -132,58 +128,31 @@ static void test_send_signal_common(struct perf_event_attr *attr,

disable_pmu:
close(pmu_fd);
close_prog:
bpf_object__close(obj);
prog_load_failure:
destroy_skel:
test_send_signal_kern__destroy(skel);
skel_open_load_failure:
close(pipe_c2p[0]);
close(pipe_p2c[1]);
wait(NULL);
}

static void test_send_signal_tracepoint(void)
static void test_send_signal_tracepoint(bool signal_thread)
{
const char *id_path = "/sys/kernel/debug/tracing/events/syscalls/sys_enter_nanosleep/id";
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];

efd = open(id_path, O_RDONLY, 0);
if (CHECK(efd < 0, "tracepoint",
"open syscalls/sys_enter_nanosleep/id failure: %s\n",
strerror(errno)))
return;

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;

attr.config = strtol(buf, NULL, 0);

test_send_signal_common(&attr, BPF_PROG_TYPE_TRACEPOINT, "tracepoint");
test_send_signal_common(NULL, signal_thread, "tracepoint");
}

static void test_send_signal_perf(void)
static void test_send_signal_perf(bool signal_thread)
{
struct perf_event_attr attr = {
.sample_period = 1,
.type = PERF_TYPE_SOFTWARE,
.config = PERF_COUNT_SW_CPU_CLOCK,
};

test_send_signal_common(&attr, BPF_PROG_TYPE_PERF_EVENT,
"perf_sw_event");
test_send_signal_common(&attr, signal_thread, "perf_sw_event");
}

static void test_send_signal_nmi(void)
static void test_send_signal_nmi(bool signal_thread)
{
struct perf_event_attr attr = {
.sample_freq = 50,
Expand All @@ -210,16 +179,21 @@ static void test_send_signal_nmi(void)
close(pmu_fd);
}

test_send_signal_common(&attr, BPF_PROG_TYPE_PERF_EVENT,
"perf_hw_event");
test_send_signal_common(&attr, signal_thread, "perf_hw_event");
}

void test_send_signal(void)
{
if (test__start_subtest("send_signal_tracepoint"))
test_send_signal_tracepoint();
test_send_signal_tracepoint(false);
if (test__start_subtest("send_signal_perf"))
test_send_signal_perf();
test_send_signal_perf(false);
if (test__start_subtest("send_signal_nmi"))
test_send_signal_nmi();
test_send_signal_nmi(false);
if (test__start_subtest("send_signal_tracepoint_thread"))
test_send_signal_tracepoint(true);
if (test__start_subtest("send_signal_perf_thread"))
test_send_signal_perf(true);
if (test__start_subtest("send_signal_nmi_thread"))
test_send_signal_nmi(true);
}
51 changes: 22 additions & 29 deletions tools/testing/selftests/bpf/progs/test_send_signal_kern.c
View file
Original file line number Diff line number Diff line change
Expand Up @@ -4,44 +4,37 @@
#include <linux/version.h>
#include "bpf_helpers.h"

struct {
__uint(type, BPF_MAP_TYPE_ARRAY);
__uint(max_entries, 1);
__type(key, __u32);
__type(value, __u64);
} info_map SEC(".maps");

struct {
__uint(type, BPF_MAP_TYPE_ARRAY);
__uint(max_entries, 1);
__type(key, __u32);
__type(value, __u64);
} status_map SEC(".maps");

SEC("send_signal_demo")
int bpf_send_signal_test(void *ctx)
__u32 sig = 0, pid = 0, status = 0, signal_thread = 0;

static __always_inline 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)
if (status != 0 || sig == 0 || pid == 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 (signal_thread)
ret = bpf_send_signal_thread(sig);
else
ret = bpf_send_signal(sig);
if (ret == 0)
*status_val = 1;
status = 1;
}

return 0;
}

SEC("tracepoint/syscalls/sys_enter_nanosleep")
int send_signal_tp(void *ctx)
{
return bpf_send_signal_test(ctx);
}

SEC("perf_event")
int send_signal_perf(void *ctx)
{
return bpf_send_signal_test(ctx);
}

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

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