Skip to content

Commit

Permalink
selftests/bpf: Augment send_signal test with remote signaling
Browse files Browse the repository at this point in the history 
Add testcases to test bpf_send_signal_task(). In these new test cases,
the main process triggers the BPF program and the forked process
receives the signals. The target process's signal handler receives a
cookie from the bpf program.

Signed-off-by: Puranjay Mohan <puranjay@kernel.org>
Signed-off-by: Andrii Nakryiko <andrii@kernel.org>
Link: https://lore.kernel.org/bpf/20241016084136.10305-3-puranjay@kernel.org
  • Loading branch information
Puranjay Mohan authored and Andrii Nakryiko committed Oct 21, 2024
1 parent 6280cf7 commit 0e14189
Show file tree
Hide file tree
Showing 2 changed files with 130 additions and 38 deletions.
133 changes: 101 additions & 32 deletions tools/testing/selftests/bpf/prog_tests/send_signal.c
View file
Original file line number Diff line number Diff line change
Expand Up @@ -8,17 +8,25 @@ static int sigusr1_received;

static void sigusr1_handler(int signum)
{
sigusr1_received = 1;
sigusr1_received = 8;
}

static void sigusr1_siginfo_handler(int s, siginfo_t *i, void *v)
{
sigusr1_received = (int)(long long)i->si_value.sival_ptr;
}

static void test_send_signal_common(struct perf_event_attr *attr,
bool signal_thread)
bool signal_thread, bool remote)
{
struct test_send_signal_kern *skel;
struct sigaction sa;
int pipe_c2p[2], pipe_p2c[2];
int err = -1, pmu_fd = -1;
volatile int j = 0;
char buf[256];
pid_t pid;
int old_prio;

if (!ASSERT_OK(pipe(pipe_c2p), "pipe_c2p"))
return;
Expand All @@ -39,11 +47,14 @@ static void test_send_signal_common(struct perf_event_attr *attr,
}

if (pid == 0) {
int old_prio;
volatile int j = 0;

/* install signal handler and notify parent */
ASSERT_NEQ(signal(SIGUSR1, sigusr1_handler), SIG_ERR, "signal");
if (remote) {
sa.sa_sigaction = sigusr1_siginfo_handler;
sa.sa_flags = SA_RESTART | SA_SIGINFO;
ASSERT_NEQ(sigaction(SIGUSR1, &sa, NULL), -1, "sigaction");
} else {
ASSERT_NEQ(signal(SIGUSR1, sigusr1_handler), SIG_ERR, "signal");
}

close(pipe_c2p[0]); /* close read */
close(pipe_p2c[1]); /* close write */
Expand All @@ -52,10 +63,12 @@ static void test_send_signal_common(struct perf_event_attr *attr,
* that if an interrupt happens, the underlying task
* is this process.
*/
errno = 0;
old_prio = getpriority(PRIO_PROCESS, 0);
ASSERT_OK(errno, "getpriority");
ASSERT_OK(setpriority(PRIO_PROCESS, 0, -20), "setpriority");
if (!remote) {
errno = 0;
old_prio = getpriority(PRIO_PROCESS, 0);
ASSERT_OK(errno, "getpriority");
ASSERT_OK(setpriority(PRIO_PROCESS, 0, -20), "setpriority");
}

/* notify parent signal handler is installed */
ASSERT_EQ(write(pipe_c2p[1], buf, 1), 1, "pipe_write");
Expand All @@ -66,20 +79,25 @@ static void test_send_signal_common(struct perf_event_attr *attr,
/* wait a little for signal handler */
for (int i = 0; i < 1000000000 && !sigusr1_received; i++) {
j /= i + j + 1;
if (!attr)
/* trigger the nanosleep tracepoint program. */
usleep(1);
if (remote)
sleep(1);
else
if (!attr)
/* trigger the nanosleep tracepoint program. */
usleep(1);
}

buf[0] = sigusr1_received ? '2' : '0';
ASSERT_EQ(sigusr1_received, 1, "sigusr1_received");
buf[0] = sigusr1_received;

ASSERT_EQ(sigusr1_received, 8, "sigusr1_received");
ASSERT_EQ(write(pipe_c2p[1], buf, 1), 1, "pipe_write");

/* wait for parent notification and exit */
ASSERT_EQ(read(pipe_p2c[0], buf, 1), 1, "pipe_read");

/* restore the old priority */
ASSERT_OK(setpriority(PRIO_PROCESS, 0, old_prio), "setpriority");
if (!remote)
ASSERT_OK(setpriority(PRIO_PROCESS, 0, old_prio), "setpriority");

close(pipe_c2p[1]);
close(pipe_p2c[0]);
Expand All @@ -93,15 +111,30 @@ static void test_send_signal_common(struct perf_event_attr *attr,
if (!ASSERT_OK_PTR(skel, "skel_open_and_load"))
goto skel_open_load_failure;

/* boost with a high priority so we got a higher chance
* that if an interrupt happens, the underlying task
* is this process.
*/
if (remote) {
errno = 0;
old_prio = getpriority(PRIO_PROCESS, 0);
ASSERT_OK(errno, "getpriority");
ASSERT_OK(setpriority(PRIO_PROCESS, 0, -20), "setpriority");
}

if (!attr) {
err = test_send_signal_kern__attach(skel);
if (!ASSERT_OK(err, "skel_attach")) {
err = -1;
goto destroy_skel;
}
} else {
pmu_fd = syscall(__NR_perf_event_open, attr, pid, -1 /* cpu */,
-1 /* group id */, 0 /* flags */);
if (!remote)
pmu_fd = syscall(__NR_perf_event_open, attr, pid, -1 /* cpu */,
-1 /* group id */, 0 /* flags */);
else
pmu_fd = syscall(__NR_perf_event_open, attr, getpid(), -1 /* cpu */,
-1 /* group id */, 0 /* flags */);
if (!ASSERT_GE(pmu_fd, 0, "perf_event_open")) {
err = -1;
goto destroy_skel;
Expand All @@ -119,11 +152,30 @@ static void test_send_signal_common(struct perf_event_attr *attr,
/* trigger the bpf send_signal */
skel->bss->signal_thread = signal_thread;
skel->bss->sig = SIGUSR1;
skel->bss->pid = pid;
if (!remote) {
skel->bss->target_pid = 0;
skel->bss->pid = pid;
} else {
skel->bss->target_pid = pid;
skel->bss->pid = getpid();
}

/* notify child that bpf program can send_signal now */
ASSERT_EQ(write(pipe_p2c[1], buf, 1), 1, "pipe_write");

/* For the remote test, the BPF program is triggered from this
* process but the other process/thread is signaled.
*/
if (remote) {
if (!attr) {
for (int i = 0; i < 10; i++)
usleep(1);
} else {
for (int i = 0; i < 100000000; i++)
j /= i + 1;
}
}

/* wait for result */
err = read(pipe_c2p[0], buf, 1);
if (!ASSERT_GE(err, 0, "reading pipe"))
Expand All @@ -133,7 +185,7 @@ static void test_send_signal_common(struct perf_event_attr *attr,
goto disable_pmu;
}

ASSERT_EQ(buf[0], '2', "incorrect result");
ASSERT_EQ(buf[0], 8, "incorrect result");

/* notify child safe to exit */
ASSERT_EQ(write(pipe_p2c[1], buf, 1), 1, "pipe_write");
Expand All @@ -142,18 +194,21 @@ static void test_send_signal_common(struct perf_event_attr *attr,
close(pmu_fd);
destroy_skel:
test_send_signal_kern__destroy(skel);
/* restore the old priority */
if (remote)
ASSERT_OK(setpriority(PRIO_PROCESS, 0, old_prio), "setpriority");
skel_open_load_failure:
close(pipe_c2p[0]);
close(pipe_p2c[1]);
wait(NULL);
}

static void test_send_signal_tracepoint(bool signal_thread)
static void test_send_signal_tracepoint(bool signal_thread, bool remote)
{
test_send_signal_common(NULL, signal_thread);
test_send_signal_common(NULL, signal_thread, remote);
}

static void test_send_signal_perf(bool signal_thread)
static void test_send_signal_perf(bool signal_thread, bool remote)
{
struct perf_event_attr attr = {
.freq = 1,
Expand All @@ -162,10 +217,10 @@ static void test_send_signal_perf(bool signal_thread)
.config = PERF_COUNT_SW_CPU_CLOCK,
};

test_send_signal_common(&attr, signal_thread);
test_send_signal_common(&attr, signal_thread, remote);
}

static void test_send_signal_nmi(bool signal_thread)
static void test_send_signal_nmi(bool signal_thread, bool remote)
{
struct perf_event_attr attr = {
.sample_period = 1,
Expand All @@ -191,21 +246,35 @@ static void test_send_signal_nmi(bool signal_thread)
close(pmu_fd);
}

test_send_signal_common(&attr, signal_thread);
test_send_signal_common(&attr, signal_thread, remote);
}

void test_send_signal(void)
{
if (test__start_subtest("send_signal_tracepoint"))
test_send_signal_tracepoint(false);
test_send_signal_tracepoint(false, false);
if (test__start_subtest("send_signal_perf"))
test_send_signal_perf(false);
test_send_signal_perf(false, false);
if (test__start_subtest("send_signal_nmi"))
test_send_signal_nmi(false);
test_send_signal_nmi(false, false);
if (test__start_subtest("send_signal_tracepoint_thread"))
test_send_signal_tracepoint(true);
test_send_signal_tracepoint(true, false);
if (test__start_subtest("send_signal_perf_thread"))
test_send_signal_perf(true);
test_send_signal_perf(true, false);
if (test__start_subtest("send_signal_nmi_thread"))
test_send_signal_nmi(true);
test_send_signal_nmi(true, false);

/* Signal remote thread and thread group */
if (test__start_subtest("send_signal_tracepoint_remote"))
test_send_signal_tracepoint(false, true);
if (test__start_subtest("send_signal_perf_remote"))
test_send_signal_perf(false, true);
if (test__start_subtest("send_signal_nmi_remote"))
test_send_signal_nmi(false, true);
if (test__start_subtest("send_signal_tracepoint_thread_remote"))
test_send_signal_tracepoint(true, true);
if (test__start_subtest("send_signal_perf_thread_remote"))
test_send_signal_perf(true, true);
if (test__start_subtest("send_signal_nmi_thread_remote"))
test_send_signal_nmi(true, true);
}
35 changes: 29 additions & 6 deletions tools/testing/selftests/bpf/progs/test_send_signal_kern.c
View file
Original file line number Diff line number Diff line change
@@ -1,27 +1,50 @@
// SPDX-License-Identifier: GPL-2.0
// Copyright (c) 2019 Facebook
#include <linux/bpf.h>
#include <vmlinux.h>
#include <linux/version.h>
#include <bpf/bpf_helpers.h>

__u32 sig = 0, pid = 0, status = 0, signal_thread = 0;
struct task_struct *bpf_task_from_pid(int pid) __ksym;
void bpf_task_release(struct task_struct *p) __ksym;
int bpf_send_signal_task(struct task_struct *task, int sig, enum pid_type type, u64 value) __ksym;

__u32 sig = 0, pid = 0, status = 0, signal_thread = 0, target_pid = 0;

static __always_inline int bpf_send_signal_test(void *ctx)
{
struct task_struct *target_task = NULL;
int ret;
u64 value;

if (status != 0 || pid == 0)
return 0;

if ((bpf_get_current_pid_tgid() >> 32) == pid) {
if (signal_thread)
ret = bpf_send_signal_thread(sig);
else
ret = bpf_send_signal(sig);
if (target_pid) {
target_task = bpf_task_from_pid(target_pid);
if (!target_task)
return 0;
value = 8;
}

if (signal_thread) {
if (target_pid)
ret = bpf_send_signal_task(target_task, sig, PIDTYPE_PID, value);
else
ret = bpf_send_signal_thread(sig);
} else {
if (target_pid)
ret = bpf_send_signal_task(target_task, sig, PIDTYPE_TGID, value);
else
ret = bpf_send_signal(sig);
}
if (ret == 0)
status = 1;
}

if (target_task)
bpf_task_release(target_task);

return 0;
}

Expand Down

0 comments on commit 0e14189

Please sign in to comment.