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Howlett" , Vlastimil Babka , Mike Rapoport , Suren Baghdasaryan , Michal Hocko , Shuah Khan , linux-mm@kvack.org, linux-kernel@vger.kernel.org, workflows@vger.kernel.org, linux-doc@vger.kernel.org, linux-kselftest@vger.kernel.org, kernel-team@meta.com Subject: Re: [PATCH v2 1/3] mm: kmemleak: default min_unref_scans to 2 for verbose auto-scan Message-ID: References: <20260731-kmemleak_hardened-v2-0-7b9689ac77cb@debian.org> <20260731-kmemleak_hardened-v2-1-7b9689ac77cb@debian.org> MIME-Version: 1.0 Content-Type: text/plain; charset=us-ascii Content-Disposition: inline In-Reply-To: <20260731-kmemleak_hardened-v2-1-7b9689ac77cb@debian.org> X-Rspamd-Server: rspam06 X-Rspamd-Queue-Id: CA28012000E X-Stat-Signature: y71b6umm97r6fq9rgceam7rzurgye3t4 X-Rspam-User: X-HE-Tag: 1785764856-447845 X-HE-Meta: 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 ccgX6wSr AyowSBfXI9y8FwSsutxIBQaVe1kXYriNpJN8Ih2Y8NvhBBBThIMURLVS6OomjbDc992J57s+H5oJg6yonjYMMpcdkBZWUifsZ42eVBgBhCQ5dZz2jDPkMRY8MGLTmOZlzSgIul/4snbe8opUNXYkf73ktDGQZU9t08whFEoB9TIzlDadCIitPew67gbiJDbKEDfODTy1oneGqY5GtezX5o5g/nBo1MD/R0qlOY7j47ZpJ3Q6fyE7skl8hRSn6kmvyBEoTZrqFxIGThX6fRl01w40kgi30VTbTBV/uQ3VALYJtkj9V67z2OMwffONHtyjN0oorXZz3w/+lGKV7aPK3XDbvYs36vVoxnanyxDVqHTjpqWw= Sender: owner-linux-mm@kvack.org Precedence: bulk X-Loop: owner-majordomo@kvack.org List-ID: List-Subscribe: List-Unsubscribe: On Fri, Jul 31, 2026 at 03:13:04AM -0700, Breno Leitao wrote: > min_unref_scans defers reporting an object as leaked until it has stayed > unreferenced for that many consecutive scans, filtering out objects that > are only transiently unreferenced during a scan. > > It defaults to 1, which reports on the first unreferenced scan. > > CONFIG_DEBUG_KMEMLEAK_VERBOSE depends on CONFIG_DEBUG_KMEMLEAK_AUTO_SCAN, > so a kernel built with it runs the scan thread periodically and the user > has opted into detailed leak reporting. A second confirming scan then > happens on its own. > > Default min_unref_scans to 2 there to suppress transient false positives, > and keep it at 1 otherwise, where a manually triggered scan is expected to > report immediately. The value stays writable through the module parameter. > > CONFIG_DEBUG_KMEMLEAK_VERBOSE defaults to n, so this does not change the > default for kernels that do not opt in. > > Signed-off-by: Breno Leitao Acked-by: Catalin Marinas