linux/tools/testing
Christian Brauner df4b2889ea
selftests/filesystems: add failfs selftests
Test the failfs semantics and both new entry points:

- fchdir(FD_FAILFS_ROOT):

  * working directory lookups and getcwd() fail
  * other sentinels are rejected
  * the state is recoverable while the root is untouched

- fchroot() with regular fds:
  * chroot parity
  * CAP_SYS_CHROOT required
  * ENOTDIR/EBADF/EINVAL checks

- fchroot(FD_FAILFS_ROOT):

  * absolute lookups, stat, statfs and opens of the root including O_PATH fail with EOPNOTSUPP
  * dirfd-anchored I/O keeps working
  * ".." walks clamp at the top of the mount tree
  * /proc magic links resolve but can't be stat through
  * absolute symlinks fail while relative symlinks keep resolving

- Unprivileged entry requires no_new_privs and is rejected for
  chrooted callers and for a shared fs_struct

- entering makes the task count as chrooted so user namespace creation
  fails

- Nothing can be mounted on top of failfs and OPEN_TREE_CLONE is
  rejected; the overmount test runs in a private mount namespace so a
  regression cannot touch the host root

- setns() to a kept mount namespace fd restores root and working
  directory

- The failfs root is inherited across fork() and absolute exec fails

- Exec by fd of a dynamically linked binary fails on opening its
  absolute PT_INTERP interpreter

The exec tests run the exec in a child so a wrongly successful exec
cannot replace the test image and masquerade as a pass.

Link: https://patch.msgid.link/20260724-work-failfs-v2-6-485dabbae185@kernel.org
Signed-off-by: Christian Brauner (Amutable) <brauner@kernel.org>
2026-07-27 17:18:00 +02:00
..
crypto/chacha20-s390 crypto: drbg - Fold include/crypto/drbg.h into crypto/drbg.c 2026-05-07 16:09:59 +08:00
cxl Replace <linux/mod_devicetable.h> by more specific <linux/device-id/*.h> (c files) 2026-07-03 07:38:17 +02:00
fault-injection
ktest ktest: Add logfile to failure directory 2026-04-20 15:23:13 -04:00
kunit kunit:tool: Don't write to stdout when it should be disabled 2026-06-07 20:10:30 -06:00
memblock liveupdate: updates for 7.2-rc1 2026-06-21 09:46:14 -07:00
nvdimm tools/testing/nvdimm: Use per-DIMM device handle 2025-11-03 16:47:13 -06:00
radix-tree MAINTAINERS: update Liam's email address 2026-04-27 05:54:25 -07:00
rbtree
scatterlist
selftests selftests/filesystems: add failfs selftests 2026-07-27 17:18:00 +02:00
shared mm/slab: improve kmem_cache_alloc_bulk 2026-06-03 18:20:43 +02:00
vma mm/vma: eliminate mmap_action->error_hook, introduce error_override 2026-06-04 14:45:00 -07:00
vsock vsock/test: add MSG_PEEK after partial recv test 2026-04-16 19:34:22 -07:00