linux-kernel - [PATCH 0/3] EDITME: cover title for b4/kunit-user-alloc

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Message-ID: <20251223-b4-kunit-user-alloc-v1-0-fb910ae0e50c@google.com>
Date: Tue, 23 Dec 2025 16:18:09 +0000
From: Brendan Jackman <jackmanb@...gle.com>
To: Brendan Higgins <brendan.higgins@...ux.dev>, David Gow <davidgow@...gle.com>, 
	Rae Moar <raemoar63@...il.com>, Kees Cook <kees@...nel.org>, Ingo Molnar <mingo@...hat.com>, 
	Peter Zijlstra <peterz@...radead.org>, Juri Lelli <juri.lelli@...hat.com>, 
	Vincent Guittot <vincent.guittot@...aro.org>, Dietmar Eggemann <dietmar.eggemann@....com>, 
	Steven Rostedt <rostedt@...dmis.org>, Ben Segall <bsegall@...gle.com>, Mel Gorman <mgorman@...e.de>, 
	Valentin Schneider <vschneid@...hat.com>, Andrew Morton <akpm@...ux-foundation.org>, 
	David Hildenbrand <david@...nel.org>, Lorenzo Stoakes <lorenzo.stoakes@...cle.com>, 
	"Liam R. Howlett" <Liam.Howlett@...cle.com>, Vlastimil Babka <vbabka@...e.cz>, 
	Mike Rapoport <rppt@...nel.org>, Suren Baghdasaryan <surenb@...gle.com>, Michal Hocko <mhocko@...e.com>
Cc: linux-kselftest@...r.kernel.org, kunit-dev@...glegroups.com, 
	linux-kernel@...r.kernel.org, linux-mm@...ck.org, 
	Brendan Jackman <jackmanb@...gle.com>
Subject: [PATCH 0/3] EDITME: cover title for b4/kunit-user-alloc

kunit_attach_mm() leaks an mm_struct (verified with dumb printf
debugging). Fix that. In the process, add a new kthread mm operation,
and clean up some nearby cleanup code in the KUnit lib.

---
Here's how I understand mm refcounts:

  funcs             | counter  | manages lifecycle of...
  --------------------------------------------------------
  mmgrab()/mmdrop() | mm_count | mm_struct and PGD
  --------------------------------------------------------
  mmget()/mmput()   | mm_users | userspace address space
  
  All mm_users references share a single reference to the mm_struct.

---
Brendan Jackman (3):
      kunit: test: Delete pointless resource API usage
      kthread: Add kthread_take_mm()
      kunit: test: fix mm_struct leak in kunit_attach_mm()

 include/linux/kthread.h |  1 +
 kernel/fork.c           |  3 +-
 kernel/kthread.c        | 36 +++++++++++++++++------
 lib/kunit/user_alloc.c  | 78 +++++--------------------------------------------
 4 files changed, 37 insertions(+), 81 deletions(-)
---
base-commit: 9448598b22c50c8a5bb77a9103e2d49f134c9578
change-id: 20251223-b4-kunit-user-alloc-6ae8df0b8a92

Best regards,
-- 
Brendan Jackman <jackmanb@...gle.com>