linux.git/tools/testing/selftests/exec/binfmt_misc_selfpin.c, branch master Linux kernel source tree selftests/exec: check that a binfmt_misc instance cannot be pinned 2026-08-03T08:08:49+00:00 Christian Brauner brauner@kernel.org 2026-07-28T12:26:33+00:00 25757bc855e388eedf86c69c382857ef2c67b08e An 'F' entry whose interpreter keeps the binfmt_misc superblock alive pins the instance that owns it forever. Cover both ways to build that: - an interpreter on the instance's own files, control file and entry file alike - and an instance used as an overlayfs lower layer. Check that an ordinary 'F' registration still succeeds so the fix stays honest about not changing what 'F' promises. Link: https://patch.msgid.link/20260728-work-binfmt_misc-selfpin-v1-2-74df5daeca5b@kernel.org Signed-off-by: Christian Brauner (Amutable) <brauner@kernel.org> 
An 'F' entry whose interpreter keeps the binfmt_misc superblock alive
pins the instance that owns it forever. Cover both ways to build that:

- an interpreter on the instance's own files, control file and entry
  file alike

- and an instance used as an overlayfs lower layer.

Check that an ordinary 'F' registration still succeeds so the fix stays
honest about not changing what 'F' promises.

Link: https://patch.msgid.link/20260728-work-binfmt_misc-selfpin-v1-2-74df5daeca5b@kernel.org
Signed-off-by: Christian Brauner (Amutable) <brauner@kernel.org>