cgroup_xattr/read_cgroupfs_xattr has two issues:
1. cgroup_xattr/read_cgroupfs_xattr messes up lo without creating a netns
first. This causes issue with other tests.
Fix this by using a different hook (lsm.s/file_open) and not messing
with lo.
2. cgroup_xattr/read_cgroupfs_xattr sets up cgroups without proper
mount namespaces.
Fix this by using the existing cgroup helpers. A new helper
set_cgroup_xattr() is added to set xattr on cgroup files.
Fixes: f4fba2d6d282 ("selftests/bpf: Add tests for bpf_cgroup_read_xattr")
Reported-by: Alexei Starovoitov <ast@xxxxxxxxxx>
Closes: https://lore.kernel.org/bpf/CAADnVQ+iqMi2HEj_iH7hsx+XJAsqaMWqSDe4tzcGAnehFWA9Sw@xxxxxxxxxxxxxx/
Signed-off-by: Song Liu <song@xxxxxxxxxx>
---
Changes v1 => v2:
1. Add the second fix above.
v1: https://lore.kernel.org/bpf/20250627165831.2979022-1-song@xxxxxxxxxx/
---
tools/testing/selftests/bpf/cgroup_helpers.c | 21 ++++
tools/testing/selftests/bpf/cgroup_helpers.h | 4 +
.../selftests/bpf/prog_tests/cgroup_xattr.c | 117 ++++--------------
.../selftests/bpf/progs/read_cgroupfs_xattr.c | 4 +-
4 files changed, 49 insertions(+), 97 deletions(-)
diff --git a/tools/testing/selftests/bpf/cgroup_helpers.c b/tools/testing/selftests/bpf/cgroup_helpers.c
index e4535451322e..15f626014872 100644
--- a/tools/testing/selftests/bpf/cgroup_helpers.c
+++ b/tools/testing/selftests/bpf/cgroup_helpers.c
@@ -4,6 +4,7 @@
#include <sys/mount.h>
#include <sys/stat.h>
#include <sys/types.h>
+#include <sys/xattr.h>
#include <linux/limits.h>
#include <stdio.h>
#include <stdlib.h>
@@ -318,6 +319,26 @@ int join_parent_cgroup(const char *relative_path)
return join_cgroup_from_top(cgroup_path);
}
+/**
+ * set_cgroup_xattr() - Set xattr on a cgroup dir
+ * @relative_path: The cgroup path, relative to the workdir, to set xattr
+ * @name: xattr name
+ * @value: xattr value
+ *
+ * This function set xattr on cgroup dir.
+ *
+ * On success, it returns 0, otherwise on failure it returns -1.
+ */
+int set_cgroup_xattr(const char *relative_path,
+ const char *name,
+ const char *value)
+{
+ char cgroup_path[PATH_MAX + 1];
+
+ format_cgroup_path(cgroup_path, relative_path);
+ return setxattr(cgroup_path, name, value, strlen(value) + 1, 0);
+}
+
/**
* __cleanup_cgroup_environment() - Delete temporary cgroups
*
diff --git a/tools/testing/selftests/bpf/cgroup_helpers.h b/tools/testing/selftests/bpf/cgroup_helpers.h
index 502845160d88..182e1ac36c95 100644
--- a/tools/testing/selftests/bpf/cgroup_helpers.h
+++ b/tools/testing/selftests/bpf/cgroup_helpers.h
@@ -26,6 +26,10 @@ int join_cgroup(const char *relative_path);
int join_root_cgroup(void);
int join_parent_cgroup(const char *relative_path);
+int set_cgroup_xattr(const char *relative_path,
+ const char *name,
+ const char *value);
+
int setup_cgroup_environment(void);
void cleanup_cgroup_environment(void);
diff --git a/tools/testing/selftests/bpf/prog_tests/cgroup_xattr.c b/tools/testing/selftests/bpf/prog_tests/cgroup_xattr.c
index 87978a0f7eb7..e0dd966e4a3e 100644
--- a/tools/testing/selftests/bpf/prog_tests/cgroup_xattr.c
+++ b/tools/testing/selftests/bpf/prog_tests/cgroup_xattr.c
@@ -7,133 +7,60 @@
#include <string.h>
#include <unistd.h>
#include <sys/socket.h>
-#include <sys/xattr.h>
-
#include <test_progs.h>
+#include "cgroup_helpers.h"
#include "read_cgroupfs_xattr.skel.h"
#include "cgroup_read_xattr.skel.h"
-#define CGROUP_FS_ROOT "/sys/fs/cgroup/"
-#define CGROUP_FS_PARENT CGROUP_FS_ROOT "foo/"
+#define CGROUP_FS_PARENT "foo/"
#define CGROUP_FS_CHILD CGROUP_FS_PARENT "bar/"
-
-static int move_pid_to_cgroup(const char *cgroup_folder, pid_t pid)
-{
- char filename[128];
- char pid_str[64];
- int procs_fd;
- int ret;
-
- snprintf(filename, sizeof(filename), "%scgroup.procs", cgroup_folder);
- snprintf(pid_str, sizeof(pid_str), "%d", pid);
-
- procs_fd = open(filename, O_WRONLY | O_APPEND);
- if (!ASSERT_OK_FD(procs_fd, "open"))
- return -1;
-
- ret = write(procs_fd, pid_str, strlen(pid_str));
- close(procs_fd);
- if (!ASSERT_GT(ret, 0, "write cgroup.procs"))
- return -1;
- return 0;
-}
-
-static void reset_cgroups_and_lo(void)
-{
- rmdir(CGROUP_FS_CHILD);
- rmdir(CGROUP_FS_PARENT);
- system("ip addr del 1.1.1.1/32 dev lo");
- system("ip link set dev lo down");
-}
+#define TMP_FILE "/tmp/selftests_cgroup_xattr"
static const char xattr_value_a[] = "bpf_selftest_value_a";
static const char xattr_value_b[] = "bpf_selftest_value_b";
static const char xattr_name[] = "user.bpf_test";
-static int setup_cgroups_and_lo(void)
-{
- int err;
-
- err = mkdir(CGROUP_FS_PARENT, 0755);
- if (!ASSERT_OK(err, "mkdir 1"))
- goto error;
- err = mkdir(CGROUP_FS_CHILD, 0755);
- if (!ASSERT_OK(err, "mkdir 2"))
- goto error;
-
- err = setxattr(CGROUP_FS_PARENT, xattr_name, xattr_value_a,
- strlen(xattr_value_a) + 1, 0);
- if (!ASSERT_OK(err, "setxattr 1"))
- goto error;
-
- err = setxattr(CGROUP_FS_CHILD, xattr_name, xattr_value_b,
- strlen(xattr_value_b) + 1, 0);
- if (!ASSERT_OK(err, "setxattr 2"))
- goto error;
-
- err = system("ip link set dev lo up");
- if (!ASSERT_OK(err, "lo up"))
- goto error;
-
- err = system("ip addr add 1.1.1.1 dev lo");
- if (!ASSERT_OK(err, "lo addr v4"))
- goto error;
-
- err = write_sysctl("/proc/sys/net/ipv4/ping_group_range", "0 0");
- if (!ASSERT_OK(err, "write_sysctl"))
- goto error;
-
- return 0;
-error:
- reset_cgroups_and_lo();
- return err;
-}
-
static void test_read_cgroup_xattr(void)
{
- struct sockaddr_in sa4 = {
- .sin_family = AF_INET,
- .sin_addr.s_addr = htonl(INADDR_LOOPBACK),
- };
+ int tmp_fd, parent_cgroup_fd = -1, child_cgroup_fd = -1;
struct read_cgroupfs_xattr *skel = NULL;
- pid_t pid = gettid();
- int sock_fd = -1;
- int connect_fd = -1;
- if (!ASSERT_OK(setup_cgroups_and_lo(), "setup_cgroups_and_lo"))
+ parent_cgroup_fd = test__join_cgroup(CGROUP_FS_PARENT);
+ if (!ASSERT_OK_FD(parent_cgroup_fd, "create parent cgroup"))
return;
- if (!ASSERT_OK(move_pid_to_cgroup(CGROUP_FS_CHILD, pid),
- "move_pid_to_cgroup"))
+ if (!ASSERT_OK(set_cgroup_xattr(CGROUP_FS_PARENT, xattr_name, xattr_value_a),
+ "set parent xattr"))
+ goto out;
+
+ child_cgroup_fd = test__join_cgroup(CGROUP_FS_CHILD);
+ if (!ASSERT_OK_FD(child_cgroup_fd, "create child cgroup"))
+ goto out;
+ if (!ASSERT_OK(set_cgroup_xattr(CGROUP_FS_CHILD, xattr_name, xattr_value_b),
+ "set child xattr"))
goto out;
skel = read_cgroupfs_xattr__open_and_load();
if (!ASSERT_OK_PTR(skel, "read_cgroupfs_xattr__open_and_load"))
goto out;
- skel->bss->target_pid = pid;
+ skel->bss->target_pid = gettid();
if (!ASSERT_OK(read_cgroupfs_xattr__attach(skel), "read_cgroupfs_xattr__attach"))
goto out;
- sock_fd = socket(AF_INET, SOCK_DGRAM, IPPROTO_ICMP);
- if (!ASSERT_OK_FD(sock_fd, "sock create"))
- goto out;
-
- connect_fd = connect(sock_fd, &sa4, sizeof(sa4));
- if (!ASSERT_OK_FD(connect_fd, "connect 1"))
- goto out;
- close(connect_fd);
+ tmp_fd = open(TMP_FILE, O_RDONLY | O_CREAT);
+ ASSERT_OK_FD(tmp_fd, "open tmp file");
+ close(tmp_fd);
ASSERT_TRUE(skel->bss->found_value_a, "found_value_a");
ASSERT_TRUE(skel->bss->found_value_b, "found_value_b");
out:
- close(connect_fd);
- close(sock_fd);
+ close(child_cgroup_fd);
+ close(parent_cgroup_fd);
read_cgroupfs_xattr__destroy(skel);
- move_pid_to_cgroup(CGROUP_FS_ROOT, pid);
- reset_cgroups_and_lo();
+ unlink(TMP_FILE);
}
void test_cgroup_xattr(void)
diff --git a/tools/testing/selftests/bpf/progs/read_cgroupfs_xattr.c b/tools/testing/selftests/bpf/progs/read_cgroupfs_xattr.c
index 855f85fc5522..405adbe5e8b0 100644
--- a/tools/testing/selftests/bpf/progs/read_cgroupfs_xattr.c
+++ b/tools/testing/selftests/bpf/progs/read_cgroupfs_xattr.c
@@ -17,8 +17,8 @@ static const char expected_value_b[] = "bpf_selftest_value_b";
bool found_value_a;
bool found_value_b;
-SEC("lsm.s/socket_connect")
-int BPF_PROG(test_socket_connect)
+SEC("lsm.s/file_open")
+int BPF_PROG(test_file_open)
{
u64 cgrp_id = bpf_get_current_cgroup_id();
struct cgroup_subsys_state *css, *tmp;
--
2.47.1
