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AJvYcCUn+bwHb4hCp+xi0WbN5NOVa/PTybP0Ns+JgnN22h6cUwUUdJ0F7K48mXoLP/ACnBSb6MTqI7mpUQ==@kvack.org X-Gm-Message-State: AOJu0YywAM6CPdSF/E8xX8camyr1NXAZfk8LCMlBEjOwNnP3UZJU4Mp4 4ZrggYlKjN6MES/ncLYlCwhNch/87meUF9BwV78DBlFsLP0OitPa5n5+ACCcncIANvXxuxrECAS MhddwdsqCj+xx0A== X-Google-Smtp-Source: AGHT+IGPr3MNh9Y63iLCh43jSDD1otDWg2upubHvHKONp3Z/jU8xumFyRt2FzEbY0GIFeXDVV9+gjwkh4PeGrQ== X-Received: from wrs12.prod.google.com ([2002:a05:6000:64c:b0:42f:bb46:77bd]) (user=jackmanb job=prod-delivery.src-stubby-dispatcher) by 2002:a05:600d:115:b0:46e:37fe:f0e6 with SMTP id 5b1f17b1804b1-47d1997e733mr103467595e9.30.1766506703258; Tue, 23 Dec 2025 08:18:23 -0800 (PST) Date: Tue, 23 Dec 2025 16:18:09 +0000 Mime-Version: 1.0 X-B4-Tracking: v=1; b=H4sIAMHASmkC/x3MTQ5AMBBA4avIrE3C+AmuIhbFlAkpaVUk0rtrL N/iey84tsIOuuQFy7c4OUyMPE1gWpVZGGWODZRRlRMVOJa4eSMX+ihR7fsxYa24mXU2NqoliPK 0rOX5r/0QwgcV4GlIZQAAAA== X-Change-Id: 20251223-b4-kunit-user-alloc-6ae8df0b8a92 X-Mailer: b4 0.14.3 Message-ID: <20251223-b4-kunit-user-alloc-v1-0-fb910ae0e50c@google.com> Subject: [PATCH 0/3] EDITME: cover title for b4/kunit-user-alloc From: Brendan Jackman To: Brendan Higgins , David Gow , Rae Moar , Kees Cook , Ingo Molnar , Peter Zijlstra , Juri Lelli , Vincent Guittot , Dietmar Eggemann , Steven Rostedt , Ben Segall , Mel Gorman , Valentin Schneider , Andrew Morton , David Hildenbrand , Lorenzo Stoakes , "Liam R. Howlett" , Vlastimil Babka , Mike Rapoport , Suren Baghdasaryan , Michal Hocko Cc: linux-kselftest@vger.kernel.org, kunit-dev@googlegroups.com, linux-kernel@vger.kernel.org, linux-mm@kvack.org, Brendan Jackman Content-Type: text/plain; charset="utf-8" X-Rspam-User: X-Rspamd-Server: rspam09 X-Rspamd-Queue-Id: BC4691A001D X-Stat-Signature: cmjg8jpcq5pck7biqky8npi4bucghb1u X-HE-Tag: 1766506704-91571 X-HE-Meta: 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 3KW3xIY4 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 X-Bogosity: Ham, tests=bogofilter, spamicity=0.000000, version=1.2.4 Sender: owner-linux-mm@kvack.org Precedence: bulk X-Loop: owner-majordomo@kvack.org List-ID: List-Subscribe: List-Unsubscribe: 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