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From: Yafang Shao <laoar.shao@gmail.com>
To: ast@kernel.org, daniel@iogearbox.net, john.fastabend@gmail.com,
	andrii@kernel.org, martin.lau@linux.dev, song@kernel.org,
	yonghong.song@linux.dev, kpsingh@kernel.org, sdf@google.com,
	haoluo@google.com, jolsa@kernel.org, tj@kernel.org
Cc: bpf@vger.kernel.org, Yafang Shao <laoar.shao@gmail.com>
Subject: [PATCH v4 bpf-next 2/6] selftests/bpf: Fix issues in setup_classid_environment()
Date: Sat, 11 Nov 2023 09:00:30 +0000	[thread overview]
Message-ID: <20231111090034.4248-3-laoar.shao@gmail.com> (raw)
In-Reply-To: <20231111090034.4248-1-laoar.shao@gmail.com>

If the net_cls subsystem is already mounted, attempting to mount it again
in setup_classid_environment() will result in a failure with the error code
EBUSY. Despite this, tmpfs will have been successfully mounted at
/sys/fs/cgroup/net_cls. Consequently, the /sys/fs/cgroup/net_cls directory
will be empty, causing subsequent setup operations to fail.

Here's an error log excerpt illustrating the issue when net_cls has already
been mounted at /sys/fs/cgroup/net_cls prior to running
setup_classid_environment():

- Before that change

  $ tools/testing/selftests/bpf/test_progs --name=cgroup_v1v2
  test_cgroup_v1v2:PASS:server_fd 0 nsec
  test_cgroup_v1v2:PASS:client_fd 0 nsec
  test_cgroup_v1v2:PASS:cgroup_fd 0 nsec
  test_cgroup_v1v2:PASS:server_fd 0 nsec
  run_test:PASS:skel_open 0 nsec
  run_test:PASS:prog_attach 0 nsec
  test_cgroup_v1v2:PASS:cgroup-v2-only 0 nsec
  (cgroup_helpers.c:248: errno: No such file or directory) Opening Cgroup Procs: /sys/fs/cgroup/net_cls/cgroup.procs
  (cgroup_helpers.c:540: errno: No such file or directory) Opening cgroup classid: /sys/fs/cgroup/net_cls/cgroup-test-work-dir/net_cls.classid
  run_test:PASS:skel_open 0 nsec
  run_test:PASS:prog_attach 0 nsec
  (cgroup_helpers.c:248: errno: No such file or directory) Opening Cgroup Procs: /sys/fs/cgroup/net_cls/cgroup-test-work-dir/cgroup.procs
  run_test:FAIL:join_classid unexpected error: 1 (errno 2)
  test_cgroup_v1v2:FAIL:cgroup-v1v2 unexpected error: -1 (errno 2)
  (cgroup_helpers.c:248: errno: No such file or directory) Opening Cgroup Procs: /sys/fs/cgroup/net_cls/cgroup.procs
  #44      cgroup_v1v2:FAIL
  Summary: 0/0 PASSED, 0 SKIPPED, 1 FAILED

- After that change
  $ tools/testing/selftests/bpf/test_progs --name=cgroup_v1v2
  #44      cgroup_v1v2:OK
  Summary: 1/0 PASSED, 0 SKIPPED, 0 FAILED

Signed-off-by: Yafang Shao <laoar.shao@gmail.com>
---
 tools/testing/selftests/bpf/cgroup_helpers.c | 18 ++++++++++++++----
 1 file changed, 14 insertions(+), 4 deletions(-)

diff --git a/tools/testing/selftests/bpf/cgroup_helpers.c b/tools/testing/selftests/bpf/cgroup_helpers.c
index 5b1da2a..10b5f42 100644
--- a/tools/testing/selftests/bpf/cgroup_helpers.c
+++ b/tools/testing/selftests/bpf/cgroup_helpers.c
@@ -523,10 +523,20 @@ int setup_classid_environment(void)
 		return 1;
 	}
 
-	if (mount("net_cls", NETCLS_MOUNT_PATH, "cgroup", 0, "net_cls") &&
-	    errno != EBUSY) {
-		log_err("mount cgroup net_cls");
-		return 1;
+	if (mount("net_cls", NETCLS_MOUNT_PATH, "cgroup", 0, "net_cls")) {
+		if (errno != EBUSY) {
+			log_err("mount cgroup net_cls");
+			return 1;
+		}
+
+		if (rmdir(NETCLS_MOUNT_PATH)) {
+			log_err("rmdir cgroup net_cls");
+			return 1;
+		}
+		if (umount(CGROUP_MOUNT_DFLT)) {
+			log_err("umount cgroup base");
+			return 1;
+		}
 	}
 
 	cleanup_classid_environment();
-- 
1.8.3.1


  parent reply	other threads:[~2023-11-11  9:00 UTC|newest]

Thread overview: 10+ messages / expand[flat|nested]  mbox.gz  Atom feed  top
2023-11-11  9:00 [PATCH v4 bpf-next 0/6] bpf: Add support for cgroup1, BPF part Yafang Shao
2023-11-11  9:00 ` [PATCH v4 bpf-next 1/6] bpf: Add a new kfunc for cgroup1 hierarchy Yafang Shao
2023-11-11  9:00 ` Yafang Shao [this message]
2023-11-11  9:00 ` [PATCH v4 bpf-next 3/6] selftests/bpf: Add parallel support for classid Yafang Shao
2023-11-11  9:00 ` [PATCH v4 bpf-next 4/6] selftests/bpf: Add a new cgroup helper get_classid_cgroup_id() Yafang Shao
2023-11-11  9:00 ` [PATCH v4 bpf-next 5/6] selftests/bpf: Add a new cgroup helper get_cgroup_hierarchy_id() Yafang Shao
2023-11-11  9:00 ` [PATCH v4 bpf-next 6/6] selftests/bpf: Add selftests for cgroup1 hierarchy Yafang Shao
2023-11-14 17:06   ` Alexei Starovoitov
2023-11-15  1:47     ` Yafang Shao
2023-11-14 17:10 ` [PATCH v4 bpf-next 0/6] bpf: Add support for cgroup1, BPF part patchwork-bot+netdevbpf

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