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 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@xxxxxxxxxxx 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@xxxxxxxxxxx --- 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 | 118 +++++++++++++++++++++ tools/testing/selftests/bpf/progs/dev_cgroup.c | 4 +- tools/testing/selftests/bpf/test_dev_cgroup.c | 85 --------------- 5 files changed, 120 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
