[PATCH bpf-next v4 0/3] selftests/bpf: convert test_dev_cgroup to test_progs

[PATCH bpf-next v4 0/3] selftests/bpf: convert test_dev_cgroup to test_progs

[Alexis Lothoré (eBPF Foundation)]

Hello,
this small series aims to integrate test_dev_cgroup in test_progs so it
could be run automatically in CI. The new version brings a few differences
with the current one:
- test now uses directly syscalls instead of wrapping commandline tools
  into system() calls
- test_progs manipulates /dev/null (eg: redirecting test logs into it), so
  disabling access to it in the bpf program confuses the tests. To fix this,
  the first commit modifies the bpf program to allow access to char devices
  1:3 (/dev/null), and disable access to char devices 1:5 (/dev/zero)
- once test is converted, add a small subtest to also check for device type
  interpretation (char or block)
- paths used in mknod tests are now in /dev instead of /tmp: due to the CI
  runner organisation and mountpoints manipulations, trying to create nodes
  in /tmp leads to errors unrelated to the test (ie, mknod calls refused by
  kernel, not the bpf program). I don't understand exactly the root cause
  at the deepest point (all I see in CI is an -ENXIO error on mknod when trying to
  create the node in tmp, and I can not make sense out of it neither
  replicate it locally), so I would gladly take inputs from anyone more
  educated than me about this.

The new test_progs part has been tested in a local qemu environment as well
as in upstream CI:

  ./test_progs -a cgroup_dev
  47/1    cgroup_dev/allow-mknod:OK
  47/2    cgroup_dev/allow-read:OK
  47/3    cgroup_dev/allow-write:OK
  47/4    cgroup_dev/deny-mknod:OK
  47/5    cgroup_dev/deny-read:OK
  47/6    cgroup_dev/deny-write:OK
  47/7    cgroup_dev/deny-mknod-wrong-type:OK
  47      cgroup_dev:OK
  Summary: 1/7 PASSED, 0 SKIPPED, 0 FAILED

---
Changes in v4:
- Fix mixup between ret and errno by testing both
- Properly apply ack tag from Stanislas
- Link to v3: https://lore.kernel.org/r/20240730-convert_dev_cgroup-v3-0-93e573b74357@bootlin.com

Changes in v3:
- delete mknod file only if it has been created
- use bpf_program__attach_cgroup() instead of bpf_prog_attach
- reorganize subtests order
- collect review/ack tags from Alan and Stanislas
- Link to v2: https://lore.kernel.org/r/20240729-convert_dev_cgroup-v2-0-4c1fc0520545@bootlin.com

Changes in v2:
- directly pass expected ret code to subtests instead of boolean pass/not
  pass
- fix faulty fd check in subtest expected to fail on open
- fix wrong subtest name
- pass test buffer and corresponding size to read/write subtests
- use correct series prefix
- Link to v1: https://lore.kernel.org/r/20240725-convert_dev_cgroup-v1-0-2c8cbd487c44@bootlin.com

---
Alexis Lothoré (eBPF Foundation) (3):
      selftests/bpf: do not disable /dev/null device access in cgroup dev test
      selftests/bpf: convert test_dev_cgroup to test_progs
      selftests/bpf: add wrong type test to cgroup dev

 tools/testing/selftests/bpf/.gitignore             |   1 -
 tools/testing/selftests/bpf/Makefile               |   2 -
 .../testing/selftests/bpf/prog_tests/cgroup_dev.c  | 125 +++++++++++++++++++++
 tools/testing/selftests/bpf/progs/dev_cgroup.c     |   4 +-
 tools/testing/selftests/bpf/test_dev_cgroup.c      |  85 --------------
 5 files changed, 127 insertions(+), 90 deletions(-)
---
base-commit: 2107cb4bff1c21110ebf7a17458a918282c1a8c9
change-id: 20240723-convert_dev_cgroup-6464b0d37f1a

Best regards,
-- 
Alexis Lothoré, Bootlin
Embedded Linux and Kernel engineering
https://bootlin.com

[PATCH bpf-next v4 1/3] selftests/bpf: do not disable /dev/null device access in cgroup dev test

[Alexis Lothoré (eBPF Foundation)]

test_dev_cgroup currently loads a small bpf program allowing any access on
urandom and zero devices, disabling access to any other device. It makes
migrating this test to test_progs impossible, since this one manipulates
extensively /dev/null.

Allow /dev/null manipulation in dev_cgroup program to make its usage in
test_progs framework possible. Update test_dev_cgroup.c as well to match
this change while it has not been removed.

Reviewed-by: Alan Maguire <alan.maguire@oracle.com>
Acked-by: Stanislav Fomichev <sdf@fomichev.me>
Signed-off-by: Alexis Lothoré (eBPF Foundation) <alexis.lothore@bootlin.com>
---
 tools/testing/selftests/bpf/progs/dev_cgroup.c |  4 ++--
 tools/testing/selftests/bpf/test_dev_cgroup.c  | 18 +++++++++---------
 2 files changed, 11 insertions(+), 11 deletions(-)

diff --git a/tools/testing/selftests/bpf/progs/dev_cgroup.c b/tools/testing/selftests/bpf/progs/dev_cgroup.c
index 79b54a4fa244..c1dfbd2b56fc 100644
--- a/tools/testing/selftests/bpf/progs/dev_cgroup.c
+++ b/tools/testing/selftests/bpf/progs/dev_cgroup.c
@@ -41,14 +41,14 @@ int bpf_prog1(struct bpf_cgroup_dev_ctx *ctx)
 	bpf_trace_printk(fmt, sizeof(fmt), ctx->major, ctx->minor);
 #endif
 
-	/* Allow access to /dev/zero and /dev/random.
+	/* Allow access to /dev/null and /dev/urandom.
 	 * Forbid everything else.
 	 */
 	if (ctx->major != 1 || type != BPF_DEVCG_DEV_CHAR)
 		return 0;
 
 	switch (ctx->minor) {
-	case 5: /* 1:5 /dev/zero */
+	case 3: /* 1:3 /dev/null */
 	case 9: /* 1:9 /dev/urandom */
 		return 1;
 	}
diff --git a/tools/testing/selftests/bpf/test_dev_cgroup.c b/tools/testing/selftests/bpf/test_dev_cgroup.c
index adeaf63cb6fa..33f544f0005a 100644
--- a/tools/testing/selftests/bpf/test_dev_cgroup.c
+++ b/tools/testing/selftests/bpf/test_dev_cgroup.c
@@ -54,25 +54,25 @@ int main(int argc, char **argv)
 		goto err;
 	}
 
-	/* All operations with /dev/zero and and /dev/urandom are allowed,
+	/* All operations with /dev/null and /dev/urandom are allowed,
 	 * everything else is forbidden.
 	 */
-	assert(system("rm -f /tmp/test_dev_cgroup_null") == 0);
-	assert(system("mknod /tmp/test_dev_cgroup_null c 1 3"));
-	assert(system("rm -f /tmp/test_dev_cgroup_null") == 0);
-
-	/* /dev/zero is whitelisted */
 	assert(system("rm -f /tmp/test_dev_cgroup_zero") == 0);
-	assert(system("mknod /tmp/test_dev_cgroup_zero c 1 5") == 0);
+	assert(system("mknod /tmp/test_dev_cgroup_zero c 1 5"));
 	assert(system("rm -f /tmp/test_dev_cgroup_zero") == 0);
 
-	assert(system("dd if=/dev/urandom of=/dev/zero count=64") == 0);
+	/* /dev/null is whitelisted */
+	assert(system("rm -f /tmp/test_dev_cgroup_null") == 0);
+	assert(system("mknod /tmp/test_dev_cgroup_null c 1 3") == 0);
+	assert(system("rm -f /tmp/test_dev_cgroup_null") == 0);
+
+	assert(system("dd if=/dev/urandom of=/dev/null count=64") == 0);
 
 	/* src is allowed, target is forbidden */
 	assert(system("dd if=/dev/urandom of=/dev/full count=64"));
 
 	/* src is forbidden, target is allowed */
-	assert(system("dd if=/dev/random of=/dev/zero count=64"));
+	assert(system("dd if=/dev/random of=/dev/null count=64"));
 
 	error = 0;
 	printf("test_dev_cgroup:PASS\n");

-- 
2.45.2

[PATCH bpf-next v4 2/3] selftests/bpf: convert test_dev_cgroup to test_progs

[Alexis Lothoré (eBPF Foundation)]

test_dev_cgroup is defined as a standalone test program, and so is not
executed in CI.

Convert it to test_progs framework so it is tested automatically in CI, and
remove the old test. In order to be able to run it in test_progs, /dev/null
must remain usable, so change the new test to test operations on devices
1:3 as valid, and operations on devices 1:5 (/dev/zero) as invalid.

Reviewed-by: Alan Maguire <alan.maguire@oracle.com>
Acked-by: Stanislav Fomichev <sdf@fomichev.me>
Signed-off-by: Alexis Lothoré (eBPF Foundation) <alexis.lothore@bootlin.com>
---
Changes in v4:
- split ret and errno testing

Changes in v3:
- delete mknod file only when is has been created
- use bpf_program__attach_cgroup instead of bpf_prog_attach
- reorder subtests
- collect review/ack tags

Changes in v2:
- pass expected return code to subtest function instead of boolean pass/not
  pass
- also pass buffer and buffer size for read/write subtests
- fix faulty fd check on read/write tests expected to fail
---
 tools/testing/selftests/bpf/.gitignore             |   1 -
 tools/testing/selftests/bpf/Makefile               |   2 -
 .../testing/selftests/bpf/prog_tests/cgroup_dev.c  | 121 +++++++++++++++++++++
 tools/testing/selftests/bpf/test_dev_cgroup.c      |  85 ---------------
 4 files changed, 121 insertions(+), 88 deletions(-)

diff --git a/tools/testing/selftests/bpf/.gitignore b/tools/testing/selftests/bpf/.gitignore
index 4e4aae8aa7ec..8f14d8faeb0b 100644
--- a/tools/testing/selftests/bpf/.gitignore
+++ b/tools/testing/selftests/bpf/.gitignore
@@ -9,7 +9,6 @@ test_lpm_map
 test_tag
 FEATURE-DUMP.libbpf
 fixdep
-test_dev_cgroup
 /test_progs
 /test_progs-no_alu32
 /test_progs-bpf_gcc
diff --git a/tools/testing/selftests/bpf/Makefile b/tools/testing/selftests/bpf/Makefile
index 564e1fdf80b6..bb02a3540d7a 100644
--- a/tools/testing/selftests/bpf/Makefile
+++ b/tools/testing/selftests/bpf/Makefile
@@ -69,7 +69,6 @@ endif
 
 # Order correspond to 'make run_tests' order
 TEST_GEN_PROGS = test_verifier test_tag test_maps test_lru_map test_lpm_map test_progs \
-	test_dev_cgroup \
 	test_sock test_sockmap get_cgroup_id_user \
 	test_cgroup_storage \
 	test_tcpnotify_user test_sysctl \
@@ -294,7 +293,6 @@ JSON_WRITER		:= $(OUTPUT)/json_writer.o
 CAP_HELPERS	:= $(OUTPUT)/cap_helpers.o
 NETWORK_HELPERS := $(OUTPUT)/network_helpers.o
 
-$(OUTPUT)/test_dev_cgroup: $(CGROUP_HELPERS) $(TESTING_HELPERS)
 $(OUTPUT)/test_skb_cgroup_id_user: $(CGROUP_HELPERS) $(TESTING_HELPERS)
 $(OUTPUT)/test_sock: $(CGROUP_HELPERS) $(TESTING_HELPERS)
 $(OUTPUT)/test_sockmap: $(CGROUP_HELPERS) $(TESTING_HELPERS)
diff --git a/tools/testing/selftests/bpf/prog_tests/cgroup_dev.c b/tools/testing/selftests/bpf/prog_tests/cgroup_dev.c
new file mode 100644
index 000000000000..8661e145ba84
--- /dev/null
+++ b/tools/testing/selftests/bpf/prog_tests/cgroup_dev.c
@@ -0,0 +1,121 @@
+// SPDX-License-Identifier: GPL-2.0
+
+#include <sys/stat.h>
+#include <sys/sysmacros.h>
+#include <errno.h>
+#include "test_progs.h"
+#include "cgroup_helpers.h"
+#include "dev_cgroup.skel.h"
+
+#define TEST_CGROUP "/test-bpf-based-device-cgroup/"
+#define TEST_BUFFER_SIZE 64
+
+static void test_mknod(const char *path, mode_t mode, int dev_major,
+		       int dev_minor, int expected_ret, int expected_errno)
+{
+	int ret;
+
+	unlink(path);
+	ret = mknod(path, mode, makedev(dev_major, dev_minor));
+	ASSERT_EQ(ret, expected_ret, "mknod");
+	if (expected_ret)
+		ASSERT_EQ(errno, expected_errno, "mknod errno");
+	else
+		unlink(path);
+}
+
+static void test_read(const char *path, char *buf, int buf_size,
+		      int expected_ret, int expected_errno)
+{
+	int ret, fd;
+
+	fd = open(path, O_RDONLY);
+
+	/* A bare open on unauthorized device should fail */
+	if (expected_ret < 0) {
+		ASSERT_EQ(fd, expected_ret, "open ret for read");
+		ASSERT_EQ(errno, expected_errno, "open errno for read");
+		if (fd >= 0)
+			close(fd);
+		return;
+	}
+
+	if (!ASSERT_OK_FD(fd, "open ret for read"))
+		return;
+
+	ret = read(fd, buf, buf_size);
+	ASSERT_EQ(ret, expected_ret, "read");
+
+	close(fd);
+}
+
+static void test_write(const char *path, char *buf, int buf_size,
+		       int expected_ret, int expected_errno)
+{
+	int ret, fd;
+
+	fd = open(path, O_WRONLY);
+
+	/* A bare open on unauthorized device should fail */
+	if (expected_ret < 0) {
+		ASSERT_EQ(fd, expected_ret, "open ret for write");
+		ASSERT_EQ(errno, expected_errno, "open errno for write");
+		if (fd >= 0)
+			close(fd);
+		return;
+	}
+
+	if (!ASSERT_OK_FD(fd, "open ret for write"))
+		return;
+
+	ret = write(fd, buf, buf_size);
+	ASSERT_EQ(ret, expected_ret, "write");
+
+	close(fd);
+}
+
+void test_cgroup_dev(void)
+{
+	char buf[TEST_BUFFER_SIZE] = "some random test data";
+	struct dev_cgroup *skel;
+	int cgroup_fd;
+
+	cgroup_fd = cgroup_setup_and_join(TEST_CGROUP);
+	if (!ASSERT_OK_FD(cgroup_fd, "cgroup switch"))
+		return;
+
+	skel = dev_cgroup__open_and_load();
+	if (!ASSERT_OK_PTR(skel, "load program"))
+		goto cleanup_cgroup;
+
+	skel->links.bpf_prog1 =
+		bpf_program__attach_cgroup(skel->progs.bpf_prog1, cgroup_fd);
+	if (!ASSERT_OK_PTR(skel->links.bpf_prog1, "attach_program"))
+		goto cleanup_progs;
+
+	if (test__start_subtest("allow-mknod"))
+		test_mknod("/dev/test_dev_cgroup_null", S_IFCHR, 1, 3, 0, 0);
+
+	if (test__start_subtest("allow-read"))
+		test_read("/dev/urandom", buf, TEST_BUFFER_SIZE,
+			  TEST_BUFFER_SIZE, 0);
+
+	if (test__start_subtest("allow-write"))
+		test_write("/dev/null", buf, TEST_BUFFER_SIZE,
+			   TEST_BUFFER_SIZE, 0);
+
+	if (test__start_subtest("deny-mknod"))
+		test_mknod("/dev/test_dev_cgroup_zero", S_IFCHR, 1, 5, -1,
+			   EPERM);
+
+	if (test__start_subtest("deny-read"))
+		test_read("/dev/random", buf, TEST_BUFFER_SIZE, -1, EPERM);
+
+	if (test__start_subtest("deny-write"))
+		test_write("/dev/zero", buf, TEST_BUFFER_SIZE, -1, EPERM);
+
+cleanup_progs:
+	dev_cgroup__destroy(skel);
+cleanup_cgroup:
+	cleanup_cgroup_environment();
+}
diff --git a/tools/testing/selftests/bpf/test_dev_cgroup.c b/tools/testing/selftests/bpf/test_dev_cgroup.c
deleted file mode 100644
index 33f544f0005a..000000000000
--- a/tools/testing/selftests/bpf/test_dev_cgroup.c
+++ /dev/null
@@ -1,85 +0,0 @@
-// SPDX-License-Identifier: GPL-2.0-only
-/* Copyright (c) 2017 Facebook
- */
-
-#include <stdio.h>
-#include <stdlib.h>
-#include <string.h>
-#include <errno.h>
-#include <assert.h>
-#include <sys/time.h>
-
-#include <linux/bpf.h>
-#include <bpf/bpf.h>
-#include <bpf/libbpf.h>
-
-#include "cgroup_helpers.h"
-#include "testing_helpers.h"
-
-#define DEV_CGROUP_PROG "./dev_cgroup.bpf.o"
-
-#define TEST_CGROUP "/test-bpf-based-device-cgroup/"
-
-int main(int argc, char **argv)
-{
-	struct bpf_object *obj;
-	int error = EXIT_FAILURE;
-	int prog_fd, cgroup_fd;
-	__u32 prog_cnt;
-
-	/* Use libbpf 1.0 API mode */
-	libbpf_set_strict_mode(LIBBPF_STRICT_ALL);
-
-	if (bpf_prog_test_load(DEV_CGROUP_PROG, BPF_PROG_TYPE_CGROUP_DEVICE,
-			  &obj, &prog_fd)) {
-		printf("Failed to load DEV_CGROUP program\n");
-		goto out;
-	}
-
-	cgroup_fd = cgroup_setup_and_join(TEST_CGROUP);
-	if (cgroup_fd < 0) {
-		printf("Failed to create test cgroup\n");
-		goto out;
-	}
-
-	/* Attach bpf program */
-	if (bpf_prog_attach(prog_fd, cgroup_fd, BPF_CGROUP_DEVICE, 0)) {
-		printf("Failed to attach DEV_CGROUP program");
-		goto err;
-	}
-
-	if (bpf_prog_query(cgroup_fd, BPF_CGROUP_DEVICE, 0, NULL, NULL,
-			   &prog_cnt)) {
-		printf("Failed to query attached programs");
-		goto err;
-	}
-
-	/* All operations with /dev/null and /dev/urandom are allowed,
-	 * everything else is forbidden.
-	 */
-	assert(system("rm -f /tmp/test_dev_cgroup_zero") == 0);
-	assert(system("mknod /tmp/test_dev_cgroup_zero c 1 5"));
-	assert(system("rm -f /tmp/test_dev_cgroup_zero") == 0);
-
-	/* /dev/null is whitelisted */
-	assert(system("rm -f /tmp/test_dev_cgroup_null") == 0);
-	assert(system("mknod /tmp/test_dev_cgroup_null c 1 3") == 0);
-	assert(system("rm -f /tmp/test_dev_cgroup_null") == 0);
-
-	assert(system("dd if=/dev/urandom of=/dev/null count=64") == 0);
-
-	/* src is allowed, target is forbidden */
-	assert(system("dd if=/dev/urandom of=/dev/full count=64"));
-
-	/* src is forbidden, target is allowed */
-	assert(system("dd if=/dev/random of=/dev/null count=64"));
-
-	error = 0;
-	printf("test_dev_cgroup:PASS\n");
-
-err:
-	cleanup_cgroup_environment();
-
-out:
-	return error;
-}

-- 
2.45.2

[PATCH bpf-next v4 3/3] selftests/bpf: add wrong type test to cgroup dev

[Alexis Lothoré (eBPF Foundation)]

Current cgroup_dev test mostly tests that device operation is accepted or
refused base on passed major/minor (and so, any operation performed during
test involves only char device)

Add a small subtest ensuring that the device type passed to bpf program
allows it to take decisions as well.

Reviewed-by: Alan Maguire <alan.maguire@oracle.com>
Acked-by: Stanislav Fomichev <sdf@fomichev.me>
Signed-off-by: Alexis Lothoré (eBPF Foundation) <alexis.lothore@bootlin.com>
---
Changes in v4:
- update parameters to test both ret and errno

Changes in v3:
- reorganize subtests order

Changes in v2:
- change test name ("null" block device does not make sense)
- use updated subtest API for this new subtest
---
 tools/testing/selftests/bpf/prog_tests/cgroup_dev.c | 4 ++++
 1 file changed, 4 insertions(+)

diff --git a/tools/testing/selftests/bpf/prog_tests/cgroup_dev.c b/tools/testing/selftests/bpf/prog_tests/cgroup_dev.c
index 8661e145ba84..5ab7547e38c0 100644
--- a/tools/testing/selftests/bpf/prog_tests/cgroup_dev.c
+++ b/tools/testing/selftests/bpf/prog_tests/cgroup_dev.c
@@ -114,6 +114,10 @@ void test_cgroup_dev(void)
 	if (test__start_subtest("deny-write"))
 		test_write("/dev/zero", buf, TEST_BUFFER_SIZE, -1, EPERM);
 
+	if (test__start_subtest("deny-mknod-wrong-type"))
+		test_mknod("/dev/test_dev_cgroup_block", S_IFBLK, 1, 3, -1,
+			   EPERM);
+
 cleanup_progs:
 	dev_cgroup__destroy(skel);
 cleanup_cgroup:

-- 
2.45.2

Re: [PATCH bpf-next v4 0/3] selftests/bpf: convert test_dev_cgroup to test_progs

[patchwork-bot+netdevbpf]

Hello:

This series was applied to bpf/bpf-next.git (master)
by Martin KaFai Lau <martin.lau@kernel.org>:

On Wed, 31 Jul 2024 08:37:24 +0200 you wrote:
> Hello,
> this small series aims to integrate test_dev_cgroup in test_progs so it
> could be run automatically in CI. The new version brings a few differences
> with the current one:
> - test now uses directly syscalls instead of wrapping commandline tools
>   into system() calls
> - test_progs manipulates /dev/null (eg: redirecting test logs into it), so
>   disabling access to it in the bpf program confuses the tests. To fix this,
>   the first commit modifies the bpf program to allow access to char devices
>   1:3 (/dev/null), and disable access to char devices 1:5 (/dev/zero)
> - once test is converted, add a small subtest to also check for device type
>   interpretation (char or block)
> - paths used in mknod tests are now in /dev instead of /tmp: due to the CI
>   runner organisation and mountpoints manipulations, trying to create nodes
>   in /tmp leads to errors unrelated to the test (ie, mknod calls refused by
>   kernel, not the bpf program). I don't understand exactly the root cause
>   at the deepest point (all I see in CI is an -ENXIO error on mknod when trying to
>   create the node in tmp, and I can not make sense out of it neither
>   replicate it locally), so I would gladly take inputs from anyone more
>   educated than me about this.
> 
> [...]

Here is the summary with links:
  - [bpf-next,v4,1/3] selftests/bpf: do not disable /dev/null device access in cgroup dev test
    https://git.kernel.org/bpf/bpf-next/c/ba6a9018502e
  - [bpf-next,v4,2/3] selftests/bpf: convert test_dev_cgroup to test_progs
    https://git.kernel.org/bpf/bpf-next/c/d83d8230e415
  - [bpf-next,v4,3/3] selftests/bpf: add wrong type test to cgroup dev
    https://git.kernel.org/bpf/bpf-next/c/84cdbff4a935

You are awesome, thank you!
-- 
Deet-doot-dot, I am a bot.
https://korg.docs.kernel.org/patchwork/pwbot.html

Re: [PATCH bpf-next v4 0/3] selftests/bpf: convert test_dev_cgroup to test_progs

[Alexis Lothoré]

On 7/31/24 20:40, patchwork-bot+netdevbpf@kernel.org wrote:
> Hello:
> 
> This series was applied to bpf/bpf-next.git (master)
> by Martin KaFai Lau <martin.lau@kernel.org>:
> 
> On Wed, 31 Jul 2024 08:37:24 +0200 you wrote:
>> Hello,
>> this small series aims to integrate test_dev_cgroup in test_progs so it
>> could be run automatically in CI. The new version brings a few differences
>> with the current one:
>> - test now uses directly syscalls instead of wrapping commandline tools
>>   into system() calls
>> - test_progs manipulates /dev/null (eg: redirecting test logs into it), so
>>   disabling access to it in the bpf program confuses the tests. To fix this,
>>   the first commit modifies the bpf program to allow access to char devices
>>   1:3 (/dev/null), and disable access to char devices 1:5 (/dev/zero)
>> - once test is converted, add a small subtest to also check for device type
>>   interpretation (char or block)
>> - paths used in mknod tests are now in /dev instead of /tmp: due to the CI
>>   runner organisation and mountpoints manipulations, trying to create nodes
>>   in /tmp leads to errors unrelated to the test (ie, mknod calls refused by
>>   kernel, not the bpf program). I don't understand exactly the root cause
>>   at the deepest point (all I see in CI is an -ENXIO error on mknod when trying to
>>   create the node in tmp, and I can not make sense out of it neither
>>   replicate it locally), so I would gladly take inputs from anyone more
>>   educated than me about this.
>>
>> [...]
> 
> Here is the summary with links:
>   - [bpf-next,v4,1/3] selftests/bpf: do not disable /dev/null device access in cgroup dev test
>     https://git.kernel.org/bpf/bpf-next/c/ba6a9018502e
>   - [bpf-next,v4,2/3] selftests/bpf: convert test_dev_cgroup to test_progs
>     https://git.kernel.org/bpf/bpf-next/c/d83d8230e415
>   - [bpf-next,v4,3/3] selftests/bpf: add wrong type test to cgroup dev
>     https://git.kernel.org/bpf/bpf-next/c/84cdbff4a935
> 
> You are awesome, thank you!

For the record, I am not receiving the notification about my patches being
merged (well, I receive it at least thanks to the mailing list, but not as the
author). I see that my email address looks pretty broken in the recipient field.
Could patchwork automation be confused by "customized" identity ?

-- 
Alexis Lothoré, Bootlin
Embedded Linux and Kernel engineering
https://bootlin.com