linux.git/tools/testing/selftests/exec/binfmt_misc_disabled.c, branch master Linux kernel source tree selftests/exec: test registering an entry disabled 2026-08-03T17:15:44+00:00 Christian Brauner brauner@kernel.org 2026-07-30T13:34:05+00:00 6bd0c7aba69873e9944ac8853d167d32c294468c A magic entry registered with 'D' and the same entry without it, to pin down what the flag decides and what it leaves alone: - the entry reports itself disabled and nothing dispatches until '1' is written to it - without 'D' it dispatches straight away - 'D' is not read back among the entry's flags - enabling and disabling afterwards works as it does for any entry - 'D' composes with the flags that shape the invocation - '-1' to the status file removes a staged entry like any other - a file handle held across a removal cannot resurrect the entry Put the entry write and read-back helpers into binfmt_misc_common.h. The bpf suite will need them as well. Link: https://patch.msgid.link/20260730-work-binfmt_misc-preopen-v1-3-4a0b0da71f16@kernel.org Signed-off-by: Christian Brauner (Amutable) <brauner@kernel.org> 
A magic entry registered with 'D' and the same entry without it, to pin
down what the flag decides and what it leaves alone:

- the entry reports itself disabled and nothing dispatches until '1' is
  written to it

- without 'D' it dispatches straight away

- 'D' is not read back among the entry's flags

- enabling and disabling afterwards works as it does for any entry

- 'D' composes with the flags that shape the invocation

- '-1' to the status file removes a staged entry like any other

- a file handle held across a removal cannot resurrect the entry

Put the entry write and read-back helpers into binfmt_misc_common.h.
The bpf suite will need them as well.

Link: https://patch.msgid.link/20260730-work-binfmt_misc-preopen-v1-3-4a0b0da71f16@kernel.org
Signed-off-by: Christian Brauner (Amutable) <brauner@kernel.org>