[PATCH v2 bpf-next 0/2] selftests/bpf: more loop tests

[PATCH v2 bpf-next 0/2] selftests/bpf: more loop tests

[Alexei Starovoitov]

Add two bounded loop tests.

v1-v2: addressed feedback from Yonghong.

Alexei Starovoitov (2):
  selftests/bpf: add loop test 4
  selftests/bpf: add loop test 5

 .../bpf/prog_tests/bpf_verif_scale.c          |  2 ++
 tools/testing/selftests/bpf/progs/loop4.c     | 18 +++++++++++
 tools/testing/selftests/bpf/progs/loop5.c     | 32 +++++++++++++++++++
 3 files changed, 52 insertions(+)
 create mode 100644 tools/testing/selftests/bpf/progs/loop4.c
 create mode 100644 tools/testing/selftests/bpf/progs/loop5.c

-- 
2.20.0

[PATCH v2 bpf-next 1/2] selftests/bpf: add loop test 4

[Alexei Starovoitov]

Add a test that returns a 'random' number between [0, 2^20)
If state pruning is not working correctly for loop body the number of
processed insns will be 2^20 * num_of_insns_in_loop_body and the program
will be rejected.

Signed-off-by: Alexei Starovoitov <ast@kernel.org>
Acked-by: Andrii Nakryiko <andriin@fb.com>
---
 .../selftests/bpf/prog_tests/bpf_verif_scale.c |  1 +
 tools/testing/selftests/bpf/progs/loop4.c      | 18 ++++++++++++++++++
 2 files changed, 19 insertions(+)
 create mode 100644 tools/testing/selftests/bpf/progs/loop4.c

diff --git a/tools/testing/selftests/bpf/prog_tests/bpf_verif_scale.c b/tools/testing/selftests/bpf/prog_tests/bpf_verif_scale.c
index b4be96162ff4..e9e72d8d7aae 100644
--- a/tools/testing/selftests/bpf/prog_tests/bpf_verif_scale.c
+++ b/tools/testing/selftests/bpf/prog_tests/bpf_verif_scale.c
@@ -71,6 +71,7 @@ void test_bpf_verif_scale(void)
 
 		{ "loop1.o", BPF_PROG_TYPE_RAW_TRACEPOINT },
 		{ "loop2.o", BPF_PROG_TYPE_RAW_TRACEPOINT },
+		{ "loop4.o", BPF_PROG_TYPE_SCHED_CLS },
 
 		/* partial unroll. 19k insn in a loop.
 		 * Total program size 20.8k insn.
diff --git a/tools/testing/selftests/bpf/progs/loop4.c b/tools/testing/selftests/bpf/progs/loop4.c
new file mode 100644
index 000000000000..650859022771
--- /dev/null
+++ b/tools/testing/selftests/bpf/progs/loop4.c
@@ -0,0 +1,18 @@
+// SPDX-License-Identifier: GPL-2.0
+// Copyright (c) 2019 Facebook
+#include <linux/bpf.h>
+#include "bpf_helpers.h"
+
+char _license[] SEC("license") = "GPL";
+
+SEC("socket")
+int combinations(volatile struct __sk_buff* skb)
+{
+	int ret = 0, i;
+
+#pragma nounroll
+	for (i = 0; i < 20; i++)
+		if (skb->len)
+			ret |= 1 << i;
+	return ret;
+}
-- 
2.20.0

[PATCH v2 bpf-next 2/2] selftests/bpf: add loop test 5

[Alexei Starovoitov]

Add a test with multiple exit conditions.
It's not an infinite loop only when the verifier can properly track
all math on variable 'i' through all possible ways of executing this loop.

barrier()s are needed to disable llvm optimization that combines multiple
branches into fewer branches.

Signed-off-by: Alexei Starovoitov <ast@kernel.org>
---
 .../bpf/prog_tests/bpf_verif_scale.c          |  1 +
 tools/testing/selftests/bpf/progs/loop5.c     | 32 +++++++++++++++++++
 2 files changed, 33 insertions(+)
 create mode 100644 tools/testing/selftests/bpf/progs/loop5.c

diff --git a/tools/testing/selftests/bpf/prog_tests/bpf_verif_scale.c b/tools/testing/selftests/bpf/prog_tests/bpf_verif_scale.c
index e9e72d8d7aae..0caf8eafa9eb 100644
--- a/tools/testing/selftests/bpf/prog_tests/bpf_verif_scale.c
+++ b/tools/testing/selftests/bpf/prog_tests/bpf_verif_scale.c
@@ -72,6 +72,7 @@ void test_bpf_verif_scale(void)
 		{ "loop1.o", BPF_PROG_TYPE_RAW_TRACEPOINT },
 		{ "loop2.o", BPF_PROG_TYPE_RAW_TRACEPOINT },
 		{ "loop4.o", BPF_PROG_TYPE_SCHED_CLS },
+		{ "loop5.o", BPF_PROG_TYPE_SCHED_CLS },
 
 		/* partial unroll. 19k insn in a loop.
 		 * Total program size 20.8k insn.
diff --git a/tools/testing/selftests/bpf/progs/loop5.c b/tools/testing/selftests/bpf/progs/loop5.c
new file mode 100644
index 000000000000..28d1d668f07c
--- /dev/null
+++ b/tools/testing/selftests/bpf/progs/loop5.c
@@ -0,0 +1,32 @@
+// SPDX-License-Identifier: GPL-2.0
+// Copyright (c) 2019 Facebook
+#include <linux/bpf.h>
+#include "bpf_helpers.h"
+#define barrier() __asm__ __volatile__("": : :"memory")
+
+char _license[] SEC("license") = "GPL";
+
+SEC("socket")
+int while_true(volatile struct __sk_buff* skb)
+{
+	int i = 0;
+
+	while (1) {
+		if (skb->len)
+			i += 3;
+		else
+			i += 7;
+		if (i == 9)
+			break;
+		barrier();
+		if (i == 10)
+			break;
+		barrier();
+		if (i == 13)
+			break;
+		barrier();
+		if (i == 14)
+			break;
+	}
+	return i;
+}
-- 
2.20.0

Re: [PATCH v2 bpf-next 0/2] selftests/bpf: more loop tests

[Yonghong Song]

On 8/5/19 7:17 PM, Alexei Starovoitov wrote:
> Add two bounded loop tests.
> 
> v1-v2: addressed feedback from Yonghong.
> 
> Alexei Starovoitov (2):
>    selftests/bpf: add loop test 4
>    selftests/bpf: add loop test 5

Looks good to me. Ack for the whole series.
Acked-by: Yonghong Song <yhs@fb.com>

> 
>   .../bpf/prog_tests/bpf_verif_scale.c          |  2 ++
>   tools/testing/selftests/bpf/progs/loop4.c     | 18 +++++++++++
>   tools/testing/selftests/bpf/progs/loop5.c     | 32 +++++++++++++++++++
>   3 files changed, 52 insertions(+)
>   create mode 100644 tools/testing/selftests/bpf/progs/loop4.c
>   create mode 100644 tools/testing/selftests/bpf/progs/loop5.c
> 

Re: [PATCH v2 bpf-next 0/2] selftests/bpf: more loop tests

[Alexei Starovoitov]

On Mon, Aug 5, 2019 at 9:19 PM Yonghong Song <yhs@fb.com> wrote:
>
>
>
> On 8/5/19 7:17 PM, Alexei Starovoitov wrote:
> > Add two bounded loop tests.
> >
> > v1-v2: addressed feedback from Yonghong.
> >
> > Alexei Starovoitov (2):
> >    selftests/bpf: add loop test 4
> >    selftests/bpf: add loop test 5
>
> Looks good to me. Ack for the whole series.
> Acked-by: Yonghong Song <yhs@fb.com>

Applied. Thanks