selftests/exec: check that a binfmt_misc instance cannot be pinned

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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>

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Christian Brauner 2026-07-28 14:26:33 +02:00

parent b2a5238154

commit 25757bc855

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10

tools/testing/selftests/exec/Makefile

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158

tools/testing/selftests/exec/binfmt_misc_selfpin.c

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3

tools/testing/selftests/exec/config

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