linux/tools/testing
Christian Brauner 32f54f2bbc
selftests/filesystems: add tests for empty mount namespaces
Add a test suite for the UNSHARE_EMPTY_MNTNS and CLONE_EMPTY_MNTNS
flags exercising the empty mount namespace functionality through the
kselftest harness.

The tests cover:

- basic functionality: unshare succeeds, exactly one mount exists in
  the new namespace, root and cwd point to the same mount
- flag interactions: UNSHARE_EMPTY_MNTNS works standalone without
  explicit CLONE_NEWNS, combines correctly with CLONE_NEWUSER and
  other namespace flags (CLONE_NEWUTS, CLONE_NEWIPC)
- edge cases: EPERM without capabilities, works from a user namespace,
  many source mounts still result in one mount, cwd on a different
  mount gets reset to root
- error paths: invalid flags return EINVAL
- regression: plain CLONE_NEWNS still copies the full mount tree,
  other namespace unshares are unaffected
- mount properties: the root mount has the expected statmount
  properties, is its own parent, and is the only entry returned by
  listmount
- repeated unshare: consecutive UNSHARE_EMPTY_MNTNS calls each
  produce a new namespace with a distinct mount ID
- overmount workflow: verifies the intended usage pattern of creating
  an empty mount namespace with a nullfs root and then mounting tmpfs
  over it to build a writable filesystem from scratch

Link: https://patch.msgid.link/20260306-work-empty-mntns-consolidated-v1-2-6eb30529bbb0@kernel.org
Signed-off-by: Christian Brauner <brauner@kernel.org>
2026-03-12 13:33:55 +01:00
..
crypto/chacha20-s390
cxl cxl changes for v7.0 2026-02-12 16:33:05 -08:00
fault-injection
ktest ktest.pl: Fix uninitialized var in config-bisect.pl 2025-12-03 18:25:18 -05:00
kunit kunit: tool: copy caller args in run_kernel to prevent mutation 2026-03-02 10:02:06 -07:00
memblock memblock: drop redundant 'struct page *' argument from memblock_free_pages() 2026-01-09 11:53:51 +02:00
nvdimm tools/testing/nvdimm: Use per-DIMM device handle 2025-11-03 16:47:13 -06:00
radix-tree idr: fix idr_alloc() returning an ID out of range 2025-12-23 11:23:11 -08:00
rbtree
scatterlist mm: remove nth_page() 2025-09-21 14:22:10 -07:00
selftests selftests/filesystems: add tests for empty mount namespaces 2026-03-12 13:33:55 +01:00
shared tools: Update context analysis macros in compiler_types.h 2026-01-28 09:25:45 +01:00
vma tools/testing/vma: add VMA userland tests for VMA flag functions 2026-02-12 15:42:59 -08:00
vsock vsock/test: add stream TX credit bounds test 2026-01-22 15:41:33 +01:00