[GIT PULL] Landlock fix for v6.12-rc7

[Mickaël Salaün]

Hi Linus,

This PR fixes issues in the Landlock's sandboxer sample and documentation,
slightly refactors helpers (required for ongoing patch series), and improve/fix
a feature merged in v6.12 (signal and abstract UNIX socket scoping).

Please pull these changes for v6.12-rc7 (or rc8, if any).  These commits merge
cleanly with your master branch.  The kernel code has been tested in the latest
linux-next releases for a few weeks, but I updated the last three patches with
cosmetic changes according to reviews.

Test coverage for security/landlock is 92.5% of 1129 lines according to
gcc/gcov-14, and it was 92.8% of 1134 lines before this PR.

Regards,
 Mickaël

--
The following changes since commit 03197e40a22c2641a1f9d1744418cd29f4954b83:

  landlock: Optimize scope enforcement (2024-11-09 19:52:13 +0100)

are available in the Git repository at:

  https://git.kernel.org/pub/scm/linux/kernel/git/mic/linux.git tags/landlock-6.12-rc7

for you to fetch changes up to 03197e40a22c2641a1f9d1744418cd29f4954b83:

  landlock: Optimize scope enforcement (2024-11-09 19:52:13 +0100)

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Landlock fix for v6.12-rc7

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