[bpf-next,v2,2/2] selftests/bpf: Add testcase for updating attached freplace prog to prog_array map

Commit Message

Leon Hwang July 26, 2024, 3:39 p.m. UTC

Add a selftest to confirm the issue, which gets -EINVAL when update
attached freplace prog to prog_array map, has been fixed.

cd tools/testing/selftests/bpf; ./test_progs -t tailcalls
327/25  tailcalls/tailcall_freplace:OK
327     tailcalls:OK
Summary: 1/25 PASSED, 0 SKIPPED, 0 FAILED

Signed-off-by: Leon Hwang <[e-mail]>
---
 .../selftests/bpf/prog_tests/tailcalls.c      | 65 ++++++++++++++++++-
 .../selftests/bpf/progs/tailcall_freplace.c   | 25 +++++++
 .../testing/selftests/bpf/progs/tc_bpf2bpf.c  | 21 ++++++
 3 files changed, 110 insertions(+), 1 deletion(-)
 create mode 100644 tools/testing/selftests/bpf/progs/tailcall_freplace.c
 create mode 100644 tools/testing/selftests/bpf/progs/tc_bpf2bpf.c

Comments

Yonghong Song July 26, 2024, 7:38 p.m. UTC | #1

On 7/26/24 8:39 AM, Leon Hwang wrote:
> Add a selftest to confirm the issue, which gets -EINVAL when update
> attached freplace prog to prog_array map, has been fixed.
>
> cd tools/testing/selftests/bpf; ./test_progs -t tailcalls
> 327/25  tailcalls/tailcall_freplace:OK
> 327     tailcalls:OK
> Summary: 1/25 PASSED, 0 SKIPPED, 0 FAILED
>
> Signed-off-by: Leon Hwang <[e-mail]>

LGTM with some comments below.

Acked-by: Yonghong Song <[e-mail]>

> ---
>   .../selftests/bpf/prog_tests/tailcalls.c      | 65 ++++++++++++++++++-
>   .../selftests/bpf/progs/tailcall_freplace.c   | 25 +++++++
>   .../testing/selftests/bpf/progs/tc_bpf2bpf.c  | 21 ++++++
>   3 files changed, 110 insertions(+), 1 deletion(-)
>   create mode 100644 tools/testing/selftests/bpf/progs/tailcall_freplace.c
>   create mode 100644 tools/testing/selftests/bpf/progs/tc_bpf2bpf.c
>
> diff --git a/tools/testing/selftests/bpf/prog_tests/tailcalls.c b/tools/testing/selftests/bpf/prog_tests/tailcalls.c
> index e01fabb8cc415..21c5a37846ade 100644
> --- a/tools/testing/selftests/bpf/prog_tests/tailcalls.c
> +++ b/tools/testing/selftests/bpf/prog_tests/tailcalls.c
> @@ -5,7 +5,8 @@
>   #include "tailcall_poke.skel.h"
>   #include "tailcall_bpf2bpf_hierarchy2.skel.h"
>   #include "tailcall_bpf2bpf_hierarchy3.skel.h"
> -
> +#include "tailcall_freplace.skel.h"
> +#include "tc_bpf2bpf.skel.h"
>   
>   /* test_tailcall_1 checks basic functionality by patching multiple locations
>    * in a single program for a single tail call slot with nop->jmp, jmp->nop
> @@ -1495,6 +1496,66 @@ static void test_tailcall_bpf2bpf_hierarchy_3(void)
>   	RUN_TESTS(tailcall_bpf2bpf_hierarchy3);
>   }
>   
> +/* test_tailcall_freplace checks that the attached freplace prog is OK to
> + * update the prog_array map.
> + */
> +static void test_tailcall_freplace(void)
> +{
> +	struct tailcall_freplace *freplace_skel = NULL;
> +	struct bpf_link *freplace_link = NULL;
> +	struct bpf_program *freplace_prog;
> +	struct tc_bpf2bpf *tc_skel = NULL;
> +	int prog_fd, map_fd;
> +	char buff[128] = {};
> +	int err, key;
> +
> +	LIBBPF_OPTS(bpf_test_run_opts, topts,
> +		    .data_in = buff,
> +		    .data_size_in = sizeof(buff),
> +		    .repeat = 1,
> +	);
> +
> +	freplace_skel = tailcall_freplace__open();
> +	if (!ASSERT_OK_PTR(freplace_skel, "tailcall_freplace__open"))
> +		return;
> +
> +	tc_skel = tc_bpf2bpf__open_and_load();
> +	if (!ASSERT_OK_PTR(tc_skel, "tc_bpf2bpf__open_and_load"))
> +		goto out;
> +
> +	prog_fd = bpf_program__fd(tc_skel->progs.entry_tc);
> +	freplace_prog = freplace_skel->progs.entry_freplace;
> +	err = bpf_program__set_attach_target(freplace_prog, prog_fd, "subprog");
> +	if (!ASSERT_OK(err, "set_attach_target"))
> +		goto out;
> +
> +	err = tailcall_freplace__load(freplace_skel);
> +	if (!ASSERT_OK(err, "tailcall_freplace__load"))
> +		goto out;
> +
> +	freplace_link = bpf_program__attach_freplace(freplace_prog, prog_fd,
> +						     "subprog");
> +	if (!ASSERT_OK_PTR(freplace_link, "attach_freplace"))
> +		goto out;
> +
> +	map_fd = bpf_map__fd(freplace_skel->maps.jmp_table);
> +	prog_fd = bpf_program__fd(freplace_prog);
> +	key = 0;
> +	err = bpf_map_update_elem(map_fd, &key, &prog_fd, BPF_ANY);
> +	if (!ASSERT_OK(err, "update jmp_table"))
> +		goto out;
> +
> +	prog_fd = bpf_program__fd(tc_skel->progs.entry_tc);
> +	err = bpf_prog_test_run_opts(prog_fd, &topts);
> +	ASSERT_OK(err, "test_run");
> +	ASSERT_EQ(topts.retval, 34, "test_run retval");
> +
> +out:
> +	bpf_link__destroy(freplace_link);
> +	tc_bpf2bpf__destroy(tc_skel);
> +	tailcall_freplace__destroy(freplace_skel);
> +}
> +
>   void test_tailcalls(void)
>   {
>   	if (test__start_subtest("tailcall_1"))
> @@ -1543,4 +1604,6 @@ void test_tailcalls(void)
>   		test_tailcall_bpf2bpf_hierarchy_fentry_entry();
>   	test_tailcall_bpf2bpf_hierarchy_2();
>   	test_tailcall_bpf2bpf_hierarchy_3();
> +	if (test__start_subtest("tailcall_freplace"))
> +		test_tailcall_freplace();
>   }
> diff --git a/tools/testing/selftests/bpf/progs/tailcall_freplace.c b/tools/testing/selftests/bpf/progs/tailcall_freplace.c
> new file mode 100644
> index 0000000000000..2966efc06ae8f
> --- /dev/null
> +++ b/tools/testing/selftests/bpf/progs/tailcall_freplace.c
> @@ -0,0 +1,25 @@
> +// SPDX-License-Identifier: GPL-2.0
> +
> +#include <linux/bpf.h>
> +#include <bpf/bpf_helpers.h>
> +
> +struct {
> +	__uint(type, BPF_MAP_TYPE_PROG_ARRAY);
> +	__uint(max_entries, 1);
> +	__uint(key_size, sizeof(__u32));
> +	__uint(value_size, sizeof(__u32));
> +} jmp_table SEC(".maps");
> +
> +int count = 0;
> +
> +SEC("freplace")
> +int entry_freplace(struct __sk_buff *skb)
> +{
> +	count++;
> +
remove empty line here.
> +	bpf_tail_call_static(skb, &jmp_table, 0);
> +
remove empty line here.
> +	return count;
> +}
> +
> +char __license[] SEC("license") = "GPL";
> diff --git a/tools/testing/selftests/bpf/progs/tc_bpf2bpf.c b/tools/testing/selftests/bpf/progs/tc_bpf2bpf.c
> new file mode 100644
> index 0000000000000..980bb810b481c
> --- /dev/null
> +++ b/tools/testing/selftests/bpf/progs/tc_bpf2bpf.c
> @@ -0,0 +1,21 @@
> +// SPDX-License-Identifier: GPL-2.0
> +
> +#include <linux/bpf.h>
> +#include <bpf/bpf_helpers.h>
> +
> +__noinline
> +int subprog(struct __sk_buff *skb)
> +{
> +	volatile int ret = 1;
> +
remove empty line here.
> +	asm volatile (""::"r+"(ret));
remove above 'volatile' key word and replace asm volatile with __sink(ret).
> +	return ret;
> +}
> +
> +SEC("tc")
> +int entry_tc(struct __sk_buff *skb)
> +{
> +	return subprog(skb);
> +}
> +
> +char __license[] SEC("license") = "GPL";

Leon Hwang July 27, 2024, 3:28 a.m. UTC | #2

On 2024/7/27 03:38, Yonghong Song wrote:
> 
> On 7/26/24 8:39 AM, Leon Hwang wrote:
>> Add a selftest to confirm the issue, which gets -EINVAL when update
>> attached freplace prog to prog_array map, has been fixed.
>>
>> cd tools/testing/selftests/bpf; ./test_progs -t tailcalls
>> 327/25  tailcalls/tailcall_freplace:OK
>> 327     tailcalls:OK
>> Summary: 1/25 PASSED, 0 SKIPPED, 0 FAILED
>>
>> Signed-off-by: Leon Hwang <[e-mail]>
> 
> LGTM with some comments below.
> 
> Acked-by: Yonghong Song <[e-mail]>
> 
>> ---
>>   .../selftests/bpf/prog_tests/tailcalls.c      | 65 ++++++++++++++++++-
>>   .../selftests/bpf/progs/tailcall_freplace.c   | 25 +++++++
>>   .../testing/selftests/bpf/progs/tc_bpf2bpf.c  | 21 ++++++
>>   3 files changed, 110 insertions(+), 1 deletion(-)
>>   create mode 100644
>> tools/testing/selftests/bpf/progs/tailcall_freplace.c
>>   create mode 100644 tools/testing/selftests/bpf/progs/tc_bpf2bpf.c
>>

[...]

>> diff --git a/tools/testing/selftests/bpf/progs/tailcall_freplace.c
>> b/tools/testing/selftests/bpf/progs/tailcall_freplace.c
>> new file mode 100644
>> index 0000000000000..2966efc06ae8f
>> --- /dev/null
>> +++ b/tools/testing/selftests/bpf/progs/tailcall_freplace.c
>> @@ -0,0 +1,25 @@
>> +// SPDX-License-Identifier: GPL-2.0
>> +
>> +#include <linux/bpf.h>
>> +#include <bpf/bpf_helpers.h>
>> +
>> +struct {
>> +    __uint(type, BPF_MAP_TYPE_PROG_ARRAY);
>> +    __uint(max_entries, 1);
>> +    __uint(key_size, sizeof(__u32));
>> +    __uint(value_size, sizeof(__u32));
>> +} jmp_table SEC(".maps");
>> +
>> +int count = 0;
>> +
>> +SEC("freplace")
>> +int entry_freplace(struct __sk_buff *skb)
>> +{
>> +    count++;
>> +
> remove empty line here.
>> +    bpf_tail_call_static(skb, &jmp_table, 0);
>> +
> remove empty line here.
>> +    return count;
>> +}
>> +
>> +char __license[] SEC("license") = "GPL";
>> diff --git a/tools/testing/selftests/bpf/progs/tc_bpf2bpf.c
>> b/tools/testing/selftests/bpf/progs/tc_bpf2bpf.c
>> new file mode 100644
>> index 0000000000000..980bb810b481c
>> --- /dev/null
>> +++ b/tools/testing/selftests/bpf/progs/tc_bpf2bpf.c
>> @@ -0,0 +1,21 @@
>> +// SPDX-License-Identifier: GPL-2.0
>> +
>> +#include <linux/bpf.h>
>> +#include <bpf/bpf_helpers.h>
>> +
>> +__noinline
>> +int subprog(struct __sk_buff *skb)
>> +{
>> +    volatile int ret = 1;
>> +
> remove empty line here.

Should we remove this empty line?

./scripts/checkpatch.pl:

WARNING: Missing a blank line after declarations
#158: FILE: tools/testing/selftests/bpf/progs/tc_bpf2bpf.c:11:
+	int ret = 1;
+	__sink(ret);

>> +    asm volatile (""::"r+"(ret));
> remove above 'volatile' key word and replace asm volatile with __sink(ret).
>> +    return ret;
>> +}
>> +
>> +SEC("tc")
>> +int entry_tc(struct __sk_buff *skb)
>> +{
>> +    return subprog(skb);
>> +}
>> +
>> +char __license[] SEC("license") = "GPL";

Yonghong Song July 27, 2024, 3:39 a.m. UTC | #3

On 7/26/24 8:28 PM, Leon Hwang wrote:
>
> On 2024/7/27 03:38, Yonghong Song wrote:
>> On 7/26/24 8:39 AM, Leon Hwang wrote:
>>> Add a selftest to confirm the issue, which gets -EINVAL when update
>>> attached freplace prog to prog_array map, has been fixed.
>>>
>>> cd tools/testing/selftests/bpf; ./test_progs -t tailcalls
>>> 327/25  tailcalls/tailcall_freplace:OK
>>> 327     tailcalls:OK
>>> Summary: 1/25 PASSED, 0 SKIPPED, 0 FAILED
>>>
>>> Signed-off-by: Leon Hwang <[e-mail]>
>> LGTM with some comments below.
>>
>> Acked-by: Yonghong Song <[e-mail]>
>>
>>> ---
>>>    .../selftests/bpf/prog_tests/tailcalls.c      | 65 ++++++++++++++++++-
>>>    .../selftests/bpf/progs/tailcall_freplace.c   | 25 +++++++
>>>    .../testing/selftests/bpf/progs/tc_bpf2bpf.c  | 21 ++++++
>>>    3 files changed, 110 insertions(+), 1 deletion(-)
>>>    create mode 100644
>>> tools/testing/selftests/bpf/progs/tailcall_freplace.c
>>>    create mode 100644 tools/testing/selftests/bpf/progs/tc_bpf2bpf.c
>>>
> [...]
>
>>> diff --git a/tools/testing/selftests/bpf/progs/tailcall_freplace.c
>>> b/tools/testing/selftests/bpf/progs/tailcall_freplace.c
>>> new file mode 100644
>>> index 0000000000000..2966efc06ae8f
>>> --- /dev/null
>>> +++ b/tools/testing/selftests/bpf/progs/tailcall_freplace.c
>>> @@ -0,0 +1,25 @@
>>> +// SPDX-License-Identifier: GPL-2.0
>>> +
>>> +#include <linux/bpf.h>
>>> +#include <bpf/bpf_helpers.h>
>>> +
>>> +struct {
>>> +    __uint(type, BPF_MAP_TYPE_PROG_ARRAY);
>>> +    __uint(max_entries, 1);
>>> +    __uint(key_size, sizeof(__u32));
>>> +    __uint(value_size, sizeof(__u32));
>>> +} jmp_table SEC(".maps");
>>> +
>>> +int count = 0;
>>> +
>>> +SEC("freplace")
>>> +int entry_freplace(struct __sk_buff *skb)
>>> +{
>>> +    count++;
>>> +
>> remove empty line here.
>>> +    bpf_tail_call_static(skb, &jmp_table, 0);
>>> +
>> remove empty line here.
>>> +    return count;
>>> +}
>>> +
>>> +char __license[] SEC("license") = "GPL";
>>> diff --git a/tools/testing/selftests/bpf/progs/tc_bpf2bpf.c
>>> b/tools/testing/selftests/bpf/progs/tc_bpf2bpf.c
>>> new file mode 100644
>>> index 0000000000000..980bb810b481c
>>> --- /dev/null
>>> +++ b/tools/testing/selftests/bpf/progs/tc_bpf2bpf.c
>>> @@ -0,0 +1,21 @@
>>> +// SPDX-License-Identifier: GPL-2.0
>>> +
>>> +#include <linux/bpf.h>
>>> +#include <bpf/bpf_helpers.h>
>>> +
>>> +__noinline
>>> +int subprog(struct __sk_buff *skb)
>>> +{
>>> +    volatile int ret = 1;
>>> +
>> remove empty line here.
> Should we remove this empty line?
>
> ./scripts/checkpatch.pl:
>
> WARNING: Missing a blank line after declarations
> #158: FILE: tools/testing/selftests/bpf/progs/tc_bpf2bpf.c:11:
> +	int ret = 1;
> +	__sink(ret);
sorry, we should keep blank line between 'int ret = 1' and '__sink(ret)'.
>
>>> +    asm volatile (""::"r+"(ret));
>> remove above 'volatile' key word and replace asm volatile with __sink(ret).
>>> +    return ret;
>>> +}
>>> +
>>> +SEC("tc")
>>> +int entry_tc(struct __sk_buff *skb)
>>> +{
>>> +    return subprog(skb);
>>> +}
>>> +
>>> +char __license[] SEC("license") = "GPL";

Patch

diff --git a/tools/testing/selftests/bpf/prog_tests/tailcalls.c b/tools/testing/selftests/bpf/prog_tests/tailcalls.c
index e01fabb8cc415..21c5a37846ade 100644
--- a/tools/testing/selftests/bpf/prog_tests/tailcalls.c
+++ b/tools/testing/selftests/bpf/prog_tests/tailcalls.c
@@ -5,7 +5,8 @@ 
 #include "tailcall_poke.skel.h"
 #include "tailcall_bpf2bpf_hierarchy2.skel.h"
 #include "tailcall_bpf2bpf_hierarchy3.skel.h"
-
+#include "tailcall_freplace.skel.h"
+#include "tc_bpf2bpf.skel.h"
 
 /* test_tailcall_1 checks basic functionality by patching multiple locations
  * in a single program for a single tail call slot with nop->jmp, jmp->nop
@@ -1495,6 +1496,66 @@  static void test_tailcall_bpf2bpf_hierarchy_3(void)
 	RUN_TESTS(tailcall_bpf2bpf_hierarchy3);
 }
 
+/* test_tailcall_freplace checks that the attached freplace prog is OK to
+ * update the prog_array map.
+ */
+static void test_tailcall_freplace(void)
+{
+	struct tailcall_freplace *freplace_skel = NULL;
+	struct bpf_link *freplace_link = NULL;
+	struct bpf_program *freplace_prog;
+	struct tc_bpf2bpf *tc_skel = NULL;
+	int prog_fd, map_fd;
+	char buff[128] = {};
+	int err, key;
+
+	LIBBPF_OPTS(bpf_test_run_opts, topts,
+		    .data_in = buff,
+		    .data_size_in = sizeof(buff),
+		    .repeat = 1,
+	);
+
+	freplace_skel = tailcall_freplace__open();
+	if (!ASSERT_OK_PTR(freplace_skel, "tailcall_freplace__open"))
+		return;
+
+	tc_skel = tc_bpf2bpf__open_and_load();
+	if (!ASSERT_OK_PTR(tc_skel, "tc_bpf2bpf__open_and_load"))
+		goto out;
+
+	prog_fd = bpf_program__fd(tc_skel->progs.entry_tc);
+	freplace_prog = freplace_skel->progs.entry_freplace;
+	err = bpf_program__set_attach_target(freplace_prog, prog_fd, "subprog");
+	if (!ASSERT_OK(err, "set_attach_target"))
+		goto out;
+
+	err = tailcall_freplace__load(freplace_skel);
+	if (!ASSERT_OK(err, "tailcall_freplace__load"))
+		goto out;
+
+	freplace_link = bpf_program__attach_freplace(freplace_prog, prog_fd,
+						     "subprog");
+	if (!ASSERT_OK_PTR(freplace_link, "attach_freplace"))
+		goto out;
+
+	map_fd = bpf_map__fd(freplace_skel->maps.jmp_table);
+	prog_fd = bpf_program__fd(freplace_prog);
+	key = 0;
+	err = bpf_map_update_elem(map_fd, &key, &prog_fd, BPF_ANY);
+	if (!ASSERT_OK(err, "update jmp_table"))
+		goto out;
+
+	prog_fd = bpf_program__fd(tc_skel->progs.entry_tc);
+	err = bpf_prog_test_run_opts(prog_fd, &topts);
+	ASSERT_OK(err, "test_run");
+	ASSERT_EQ(topts.retval, 34, "test_run retval");
+
+out:
+	bpf_link__destroy(freplace_link);
+	tc_bpf2bpf__destroy(tc_skel);
+	tailcall_freplace__destroy(freplace_skel);
+}
+
 void test_tailcalls(void)
 {
 	if (test__start_subtest("tailcall_1"))
@@ -1543,4 +1604,6 @@  void test_tailcalls(void)
 		test_tailcall_bpf2bpf_hierarchy_fentry_entry();
 	test_tailcall_bpf2bpf_hierarchy_2();
 	test_tailcall_bpf2bpf_hierarchy_3();
+	if (test__start_subtest("tailcall_freplace"))
+		test_tailcall_freplace();
 }
diff --git a/tools/testing/selftests/bpf/progs/tailcall_freplace.c b/tools/testing/selftests/bpf/progs/tailcall_freplace.c
new file mode 100644
index 0000000000000..2966efc06ae8f
--- /dev/null
+++ b/tools/testing/selftests/bpf/progs/tailcall_freplace.c
@@ -0,0 +1,25 @@ 
+// SPDX-License-Identifier: GPL-2.0
+
+#include <linux/bpf.h>
+#include <bpf/bpf_helpers.h>
+
+struct {
+	__uint(type, BPF_MAP_TYPE_PROG_ARRAY);
+	__uint(max_entries, 1);
+	__uint(key_size, sizeof(__u32));
+	__uint(value_size, sizeof(__u32));
+} jmp_table SEC(".maps");
+
+int count = 0;
+
+SEC("freplace")
+int entry_freplace(struct __sk_buff *skb)
+{
+	count++;
+
+	bpf_tail_call_static(skb, &jmp_table, 0);
+
+	return count;
+}
+
+char __license[] SEC("license") = "GPL";
diff --git a/tools/testing/selftests/bpf/progs/tc_bpf2bpf.c b/tools/testing/selftests/bpf/progs/tc_bpf2bpf.c
new file mode 100644
index 0000000000000..980bb810b481c
--- /dev/null
+++ b/tools/testing/selftests/bpf/progs/tc_bpf2bpf.c
@@ -0,0 +1,21 @@ 
+// SPDX-License-Identifier: GPL-2.0
+
+#include <linux/bpf.h>
+#include <bpf/bpf_helpers.h>
+
+__noinline
+int subprog(struct __sk_buff *skb)
+{
+	volatile int ret = 1;
+
+	asm volatile (""::"r+"(ret));
+	return ret;
+}
+
+SEC("tc")
+int entry_tc(struct __sk_buff *skb)
+{
+	return subprog(skb);
+}
+
+char __license[] SEC("license") = "GPL";