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h=From:To:Cc:Subject:Date; b=DPADvE44OdGjcfTQ/fQBi4gUAEwzjHBOqoGlpFqaw13QV/7IKHEMRAwEgDomyjuDN Yj7OoSXF+QkhqjwJ23cWxn+yMSVUCgvdhO24kOgWUCVRaQLeEA6pE3XAbjYfQmQ5+l RSRvqAwR0TSRQhXIn1AlmiG54MAOnjGhNmXBQgFNLgrfbEqeF8FHLFLiEL7rZorx8n otDZkK2LjgPDstNoG0jQGvB5S0XW33BH57GkZicrXvT3HyR+UkTX8cbRDCKU/scJ3q IQKT7RcEdLS6yMLqpdavfBZ/0U0RubpyKG3Ra88sk3kdVMqT7+K8MVYG5U/cprbNjV AucIoElM6yn1g== From: SJ Park To: Cc: SJ Park , stable@vger.kernel.org, Andrew Morton , Brendan Higgins , David Gow , Fernand Sieber , Leonard Foerster , SeongJae Park , Shakeel Butt , damon@lists.linux.dev, kunit-dev@googlegroups.com, linux-kernel@vger.kernel.org, linux-kselftest@vger.kernel.org, linux-mm@kvack.org Subject: [RFC PATCH v1.1 0/5] mm/damon: unurgent fixes for infinite loop, NULL de-ref and races Date: Sun, 12 Jul 2026 10:03:22 -0700 Message-ID: <20260712170328.91144-1-sj@kernel.org> X-Mailer: git-send-email 2.47.3 MIME-Version: 1.0 Content-Transfer-Encoding: 8bit X-Rspam-User: X-Rspamd-Server: rspam11 X-Rspamd-Queue-Id: B9886140005 X-Stat-Signature: daueaqou8oxie6jbhn7pumnkubsutkrn X-HE-Tag: 1783875819-244512 X-HE-Meta: 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 48lq/qf5 JOSx83jAfx1pDeUrsR0JEnkkQCb0bCL/UqUla4/A32yUgANdPSmPHJ04tzTTF0aVv81yilM+0Z/n3e6s5hC3XyGHYQ4a/rZJzQS1+f8nky8/8d5eK9s8zOX5KhMdavD7/Tyh7gXdQ1mHkRRsd4e6TL06hZ/qeKta8UEHazf84ebVD+WOG25hw4/3y1/E/3xXPgdXpH6UyUrfGiCa31xwYIiieVo9XTxKFSPA4GRuZc+V/OHU= Sender: owner-linux-mm@kvack.org Precedence: bulk X-Loop: owner-majordomo@kvack.org List-ID: List-Subscribe: List-Unsubscribe: Sashiko found a few issues in DAMON that could cause infinite loop, NULL dereference and monitoring results degradation. The first two sounds scary but the infinite loop happens only under unreasonable user setup. The NULL dereference is only in a unit test. Monitoring results degradation is trivial since it is only best-effort, and those happens from only unlikely races. Still those are bugs that better to fix if possible. Fix those. Changes from RFC - RFC: https://lore.kernel.org/20260711180409.82093-1-sj@kernel.org - Rebase to mm-new. SJ Park (5): mm/damon/core: avoid infinite kdamond_merge_regions() internal loop mm/damon/tests/core-kunit: catch test failure in test_merge_regions_of() mm/damon/vaddr: drop last same folio access check optimization mm/damon/paddr: drop last same folio access check reuse optimization mm/damon/sysfs: read ops_id only once mm/damon/core.c | 13 +++++++++---- mm/damon/paddr.c | 20 ++++---------------- mm/damon/sysfs.c | 6 ++++-- mm/damon/tests/core-kunit.h | 3 +++ mm/damon/vaddr.c | 26 ++++---------------------- 5 files changed, 24 insertions(+), 44 deletions(-) base-commit: df701015aac3c13b1ecff311fda1a2ada2b9c1b2 -- 2.47.3