[PATCH v4 bpf-next 0/3] BPF test_progs tests improvement

[PATCH v4 bpf-next 0/3] BPF test_progs tests improvement

[Mykola Lysenko]

First patch reduces the sample_freq to 1000 to ensure test will
work even when kernel.perf_event_max_sample_rate was reduced to 1000.

Patches for send_signal and find_vma tune the test implementation to
make sure needed thread is scheduled. Also, both tests will finish as
soon as possible after the test condition is met.

Mykola Lysenko (3):
  Improve perf related BPF tests (sample_freq issue)
  Improve send_signal BPF test stability
  Improve stability of find_vma BPF test

 .../selftests/bpf/prog_tests/bpf_cookie.c       |  2 +-
 .../testing/selftests/bpf/prog_tests/find_vma.c | 13 ++++++++++---
 .../selftests/bpf/prog_tests/perf_branches.c    |  4 ++--
 .../selftests/bpf/prog_tests/perf_link.c        |  2 +-
 .../selftests/bpf/prog_tests/send_signal.c      | 17 ++++++++++-------
 .../selftests/bpf/progs/test_send_signal_kern.c |  2 +-
 6 files changed, 25 insertions(+), 15 deletions(-)

-- 
2.30.2

[PATCH v4 bpf-next 1/3] Improve perf related BPF tests (sample_freq issue)

[Mykola Lysenko]

Linux kernel may automatically reduce kernel.perf_event_max_sample_rate
value when running tests in parallel on slow systems. Linux kernel checks
against this limit when opening perf event with freq=1 parameter set.
The lower bound is 1000. This patch reduces sample_freq value to 1000
in all BPF tests that use sample_freq to ensure they always can open
perf event.

Signed-off-by: Mykola Lysenko <mykolal@fb.com>
Acked-by: Yonghong Song <yhs@fb.com>
---
 tools/testing/selftests/bpf/prog_tests/bpf_cookie.c    | 2 +-
 tools/testing/selftests/bpf/prog_tests/find_vma.c      | 2 +-
 tools/testing/selftests/bpf/prog_tests/perf_branches.c | 4 ++--
 tools/testing/selftests/bpf/prog_tests/perf_link.c     | 2 +-
 4 files changed, 5 insertions(+), 5 deletions(-)

diff --git a/tools/testing/selftests/bpf/prog_tests/bpf_cookie.c b/tools/testing/selftests/bpf/prog_tests/bpf_cookie.c
index cd10df6cd0fc..0612e79a9281 100644
--- a/tools/testing/selftests/bpf/prog_tests/bpf_cookie.c
+++ b/tools/testing/selftests/bpf/prog_tests/bpf_cookie.c
@@ -199,7 +199,7 @@ static void pe_subtest(struct test_bpf_cookie *skel)
 	attr.type = PERF_TYPE_SOFTWARE;
 	attr.config = PERF_COUNT_SW_CPU_CLOCK;
 	attr.freq = 1;
-	attr.sample_freq = 4000;
+	attr.sample_freq = 1000;
 	pfd = syscall(__NR_perf_event_open, &attr, -1, 0, -1, PERF_FLAG_FD_CLOEXEC);
 	if (!ASSERT_GE(pfd, 0, "perf_fd"))
 		goto cleanup;
diff --git a/tools/testing/selftests/bpf/prog_tests/find_vma.c b/tools/testing/selftests/bpf/prog_tests/find_vma.c
index b74b3c0c555a..743a094c9510 100644
--- a/tools/testing/selftests/bpf/prog_tests/find_vma.c
+++ b/tools/testing/selftests/bpf/prog_tests/find_vma.c
@@ -30,7 +30,7 @@ static int open_pe(void)
 	attr.type = PERF_TYPE_HARDWARE;
 	attr.config = PERF_COUNT_HW_CPU_CYCLES;
 	attr.freq = 1;
-	attr.sample_freq = 4000;
+	attr.sample_freq = 1000;
 	pfd = syscall(__NR_perf_event_open, &attr, 0, -1, -1, PERF_FLAG_FD_CLOEXEC);
 
 	return pfd >= 0 ? pfd : -errno;
diff --git a/tools/testing/selftests/bpf/prog_tests/perf_branches.c b/tools/testing/selftests/bpf/prog_tests/perf_branches.c
index 12c4f45cee1a..bc24f83339d6 100644
--- a/tools/testing/selftests/bpf/prog_tests/perf_branches.c
+++ b/tools/testing/selftests/bpf/prog_tests/perf_branches.c
@@ -110,7 +110,7 @@ static void test_perf_branches_hw(void)
 	attr.type = PERF_TYPE_HARDWARE;
 	attr.config = PERF_COUNT_HW_CPU_CYCLES;
 	attr.freq = 1;
-	attr.sample_freq = 4000;
+	attr.sample_freq = 1000;
 	attr.sample_type = PERF_SAMPLE_BRANCH_STACK;
 	attr.branch_sample_type = PERF_SAMPLE_BRANCH_USER | PERF_SAMPLE_BRANCH_ANY;
 	pfd = syscall(__NR_perf_event_open, &attr, -1, 0, -1, PERF_FLAG_FD_CLOEXEC);
@@ -151,7 +151,7 @@ static void test_perf_branches_no_hw(void)
 	attr.type = PERF_TYPE_SOFTWARE;
 	attr.config = PERF_COUNT_SW_CPU_CLOCK;
 	attr.freq = 1;
-	attr.sample_freq = 4000;
+	attr.sample_freq = 1000;
 	pfd = syscall(__NR_perf_event_open, &attr, -1, 0, -1, PERF_FLAG_FD_CLOEXEC);
 	if (CHECK(pfd < 0, "perf_event_open", "err %d\n", pfd))
 		return;
diff --git a/tools/testing/selftests/bpf/prog_tests/perf_link.c b/tools/testing/selftests/bpf/prog_tests/perf_link.c
index ede07344f264..224eba6fef2e 100644
--- a/tools/testing/selftests/bpf/prog_tests/perf_link.c
+++ b/tools/testing/selftests/bpf/prog_tests/perf_link.c
@@ -39,7 +39,7 @@ void serial_test_perf_link(void)
 	attr.type = PERF_TYPE_SOFTWARE;
 	attr.config = PERF_COUNT_SW_CPU_CLOCK;
 	attr.freq = 1;
-	attr.sample_freq = 4000;
+	attr.sample_freq = 1000;
 	pfd = syscall(__NR_perf_event_open, &attr, -1, 0, -1, PERF_FLAG_FD_CLOEXEC);
 	if (!ASSERT_GE(pfd, 0, "perf_fd"))
 		goto cleanup;
-- 
2.30.2

[PATCH v4 bpf-next 2/3] Improve send_signal BPF test stability

[Mykola Lysenko]

Substitute sleep with dummy CPU intensive computation.
Finish aforemention computation as soon as signal was
delivered to the test process. Make the BPF code to
only execute when PID global variable is set

Signed-off-by: Mykola Lysenko <mykolal@fb.com>
Acked-by: Yonghong Song <yhs@fb.com>
---
 .../selftests/bpf/prog_tests/send_signal.c      | 17 ++++++++++-------
 .../selftests/bpf/progs/test_send_signal_kern.c |  2 +-
 2 files changed, 11 insertions(+), 8 deletions(-)

diff --git a/tools/testing/selftests/bpf/prog_tests/send_signal.c b/tools/testing/selftests/bpf/prog_tests/send_signal.c
index 776916b61c40..def50f1c5c31 100644
--- a/tools/testing/selftests/bpf/prog_tests/send_signal.c
+++ b/tools/testing/selftests/bpf/prog_tests/send_signal.c
@@ -4,11 +4,11 @@
 #include <sys/resource.h>
 #include "test_send_signal_kern.skel.h"
 
-int sigusr1_received = 0;
+static int sigusr1_received;
 
 static void sigusr1_handler(int signum)
 {
-	sigusr1_received++;
+	sigusr1_received = 1;
 }
 
 static void test_send_signal_common(struct perf_event_attr *attr,
@@ -40,9 +40,10 @@ 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 */
-		signal(SIGUSR1, sigusr1_handler);
+		ASSERT_NEQ(signal(SIGUSR1, sigusr1_handler), SIG_ERR, "signal");
 
 		close(pipe_c2p[0]); /* close read */
 		close(pipe_p2c[1]); /* close write */
@@ -63,9 +64,11 @@ static void test_send_signal_common(struct perf_event_attr *attr,
 		ASSERT_EQ(read(pipe_p2c[0], buf, 1), 1, "pipe_read");
 
 		/* wait a little for signal handler */
-		sleep(1);
+		for (int i = 0; i < 100000000 && !sigusr1_received; i++)
+			j /= i + 1;
 
 		buf[0] = sigusr1_received ? '2' : '0';
+		ASSERT_EQ(sigusr1_received, 1, "sigusr1_received");
 		ASSERT_EQ(write(pipe_c2p[1], buf, 1), 1, "pipe_write");
 
 		/* wait for parent notification and exit */
@@ -93,7 +96,7 @@ static void test_send_signal_common(struct perf_event_attr *attr,
 			goto destroy_skel;
 		}
 	} else {
-		pmu_fd = syscall(__NR_perf_event_open, attr, pid, -1,
+		pmu_fd = syscall(__NR_perf_event_open, attr, pid, -1 /* cpu */,
 				 -1 /* group id */, 0 /* flags */);
 		if (!ASSERT_GE(pmu_fd, 0, "perf_event_open")) {
 			err = -1;
@@ -110,9 +113,9 @@ static void test_send_signal_common(struct perf_event_attr *attr,
 	ASSERT_EQ(read(pipe_c2p[0], buf, 1), 1, "pipe_read");
 
 	/* trigger the bpf send_signal */
-	skel->bss->pid = pid;
-	skel->bss->sig = SIGUSR1;
 	skel->bss->signal_thread = signal_thread;
+	skel->bss->sig = SIGUSR1;
+	skel->bss->pid = pid;
 
 	/* notify child that bpf program can send_signal now */
 	ASSERT_EQ(write(pipe_p2c[1], buf, 1), 1, "pipe_write");
diff --git a/tools/testing/selftests/bpf/progs/test_send_signal_kern.c b/tools/testing/selftests/bpf/progs/test_send_signal_kern.c
index b4233d3efac2..92354cd72044 100644
--- a/tools/testing/selftests/bpf/progs/test_send_signal_kern.c
+++ b/tools/testing/selftests/bpf/progs/test_send_signal_kern.c
@@ -10,7 +10,7 @@ static __always_inline int bpf_send_signal_test(void *ctx)
 {
 	int ret;
 
-	if (status != 0 || sig == 0 || pid == 0)
+	if (status != 0 || pid == 0)
 		return 0;
 
 	if ((bpf_get_current_pid_tgid() >> 32) == pid) {
-- 
2.30.2

[PATCH v4 bpf-next 3/3] Improve stability of find_vma BPF test

[Mykola Lysenko]

Remove unneeded spleep and increase length of dummy CPU
intensive computation to guarantee test process execution.
Also, complete aforemention computation as soon as
test success criteria is met

Signed-off-by: Mykola Lysenko <mykolal@fb.com>
Acked-by: Yonghong Song <yhs@fb.com>
---
 .../selftests/bpf/prog_tests/find_vma.c       | 28 +++++++++++++------
 1 file changed, 19 insertions(+), 9 deletions(-)

diff --git a/tools/testing/selftests/bpf/prog_tests/find_vma.c b/tools/testing/selftests/bpf/prog_tests/find_vma.c
index 743a094c9510..5165b38f0e59 100644
--- a/tools/testing/selftests/bpf/prog_tests/find_vma.c
+++ b/tools/testing/selftests/bpf/prog_tests/find_vma.c
@@ -7,12 +7,14 @@
 #include "find_vma_fail1.skel.h"
 #include "find_vma_fail2.skel.h"
 
-static void test_and_reset_skel(struct find_vma *skel, int expected_find_zero_ret)
+static void test_and_reset_skel(struct find_vma *skel, int expected_find_zero_ret, bool need_test)
 {
-	ASSERT_EQ(skel->bss->found_vm_exec, 1, "found_vm_exec");
-	ASSERT_EQ(skel->data->find_addr_ret, 0, "find_addr_ret");
-	ASSERT_EQ(skel->data->find_zero_ret, expected_find_zero_ret, "find_zero_ret");
-	ASSERT_OK_PTR(strstr(skel->bss->d_iname, "test_progs"), "find_test_progs");
+	if (need_test) {
+		ASSERT_EQ(skel->bss->found_vm_exec, 1, "found_vm_exec");
+		ASSERT_EQ(skel->data->find_addr_ret, 0, "find_addr_ret");
+		ASSERT_EQ(skel->data->find_zero_ret, expected_find_zero_ret, "find_zero_ret");
+		ASSERT_OK_PTR(strstr(skel->bss->d_iname, "test_progs"), "find_test_progs");
+	}
 
 	skel->bss->found_vm_exec = 0;
 	skel->data->find_addr_ret = -1;
@@ -36,11 +38,20 @@ static int open_pe(void)
 	return pfd >= 0 ? pfd : -errno;
 }
 
+static bool find_vma_pe_condition(struct find_vma *skel)
+{
+	return skel->bss->found_vm_exec == 0 ||
+		skel->data->find_addr_ret != 0 ||
+		skel->data->find_zero_ret == -1 ||
+		strcmp(skel->bss->d_iname, "test_progs") != 0;
+}
+
 static void test_find_vma_pe(struct find_vma *skel)
 {
 	struct bpf_link *link = NULL;
 	volatile int j = 0;
 	int pfd, i;
+	const int one_bn = 1000000000;
 
 	pfd = open_pe();
 	if (pfd < 0) {
@@ -57,10 +68,10 @@ static void test_find_vma_pe(struct find_vma *skel)
 	if (!ASSERT_OK_PTR(link, "attach_perf_event"))
 		goto cleanup;
 
-	for (i = 0; i < 1000000; ++i)
+	for (i = 0; i < one_bn && find_vma_pe_condition(skel); ++i)
 		++j;
 
-	test_and_reset_skel(skel, -EBUSY /* in nmi, irq_work is busy */);
+	test_and_reset_skel(skel, -EBUSY /* in nmi, irq_work is busy */, i == one_bn);
 cleanup:
 	bpf_link__destroy(link);
 	close(pfd);
@@ -75,7 +86,7 @@ static void test_find_vma_kprobe(struct find_vma *skel)
 		return;
 
 	getpgid(skel->bss->target_pid);
-	test_and_reset_skel(skel, -ENOENT /* could not find vma for ptr 0 */);
+	test_and_reset_skel(skel, -ENOENT /* could not find vma for ptr 0 */, true);
 }
 
 static void test_illegal_write_vma(void)
@@ -108,7 +119,6 @@ void serial_test_find_vma(void)
 	skel->bss->addr = (__u64)(uintptr_t)test_find_vma_pe;
 
 	test_find_vma_pe(skel);
-	usleep(100000); /* allow the irq_work to finish */
 	test_find_vma_kprobe(skel);
 
 	find_vma__destroy(skel);
-- 
2.30.2

Re: [PATCH v4 bpf-next 0/3] BPF test_progs tests improvement

[patchwork-bot+netdevbpf]

Hello:

This series was applied to bpf/bpf-next.git (master)
by Andrii Nakryiko <andrii@kernel.org>:

On Tue, 8 Mar 2022 12:04:46 -0800 you wrote:
> First patch reduces the sample_freq to 1000 to ensure test will
> work even when kernel.perf_event_max_sample_rate was reduced to 1000.
> 
> Patches for send_signal and find_vma tune the test implementation to
> make sure needed thread is scheduled. Also, both tests will finish as
> soon as possible after the test condition is met.
> 
> [...]

Here is the summary with links:
  - [v4,bpf-next,1/3] Improve perf related BPF tests (sample_freq issue)
    https://git.kernel.org/bpf/bpf-next/c/d4b540544499
  - [v4,bpf-next,2/3] Improve send_signal BPF test stability
    https://git.kernel.org/bpf/bpf-next/c/1fd49864127c
  - [v4,bpf-next,3/3] Improve stability of find_vma BPF test
    https://git.kernel.org/bpf/bpf-next/c/ba83af059153

You are awesome, thank you!
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