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h=Date:From:To:Cc:Subject:References:In-Reply-To:From; b=RgnqxIc5A4hDNvmmDuRfbNnVTc1TmQsuhtYOj0JrWT0jRmjBA2CTQTTgKP6AtG9IE nOxRxSNT6pRHgpIueuJUzx/ZQBqUTxeJoI/kb2gHgp3LUHvdF4ctZJdVldyCIBZRk7 ZCqz25FYqnn6ZYxygxEuZZtRXt2nEt+8UReW3QVk= Date: Mon, 3 Aug 2026 14:41:20 +0100 From: Catalin Marinas To: Breno Leitao Cc: Andrew Morton , linux-mm@kvack.org, linux-kernel@vger.kernel.org, kernel-team@meta.com Subject: Re: [PATCH] mm: kmemleak: default min_unref_scans to 2 for verbose auto-scan Message-ID: References: <20260730-kmemleak_hardened-v1-1-b0b20033b4bb@debian.org> MIME-Version: 1.0 Content-Type: text/plain; charset=us-ascii Content-Disposition: inline In-Reply-To: <20260730-kmemleak_hardened-v1-1-b0b20033b4bb@debian.org> X-Rspamd-Server: rspam05 X-Rspamd-Queue-Id: E2C5C1C000B X-Rspam-User: X-Stat-Signature: erdqcqstt5hz96f5t3ik1djbwmmds7io X-HE-Tag: 1785764485-279686 X-HE-Meta: U2FsdGVkX18mEpbsNj0/ywLuiFe2Y8BysGHg60ejqMTaaBpBJNrSojgDBoVtibveCdO4lL9tUNyL//7bJ4X3aTIkOr9fKedtpP6ewVC61/e1zuwEbS0gsvL+3sa15vU9U9+moNxi+nd4MQ2abrNaxc5Y8SvKgTDuLHSu388MxLm+JDye0wTxzLAOrv9mfWw2Hl3OtII5tTheqgFkY+NYdNvCEh7pMwumddJ8jHma3aItKDX8rAm3cseMVOBxpbqhT0obbgRC2EkhUCh8XqRrVoVFmncGikFfMvKpvg6LSE6GBvBwN5shyBfZchohEDlv0h8fjxy9AGRSG1cWYT93JAGo9HXAnS/QARbA7ORwiSn3sBDBe6bLslX0N6WVGOvxyeLKOPJZeT2a2qnpXM6EvD5Y1PiBjjkVs/KDpagzRe8hOTtuTcHuvgIP3eV3JkfhTKZ3eSf92lmpeaTkFG5qUUL4enCQCSjjeYcGqcqU+v708XZRMuBI5pczJ7LShjpJ+bMCcT/3iyZub84L3L+GWi7EZ/GXO70KPig5NIE/On86L/pSUKPLPMad2vP0PpSVcygyGG3cfXXpmeIAhI82eVEA2RWDfIVxXuKEffKtOoVhfCsahpT8/RnySIBiDzAYDcOP5QZC/ZoNTx7OfL3sBLuSbVtTl9n9oPXTHMmNpSeUhOBJWzP5gb14AxZL8k8wzrWCA4ejwM3x7ZFjx3vG7b6bq96hssdU7qlof9X+THyDtb8U075B7NnsGJVPc96GO6rkEt0oA4rR/kXJwwk/EdvTBtpfgTbVwnemkf6atwzIdF+NyP+JL9vcqtTItnak8x6l0ACFJ6sY6xED8W5B9fl9EsT1RbAVt7ZY/9yz8RVrRrk4zvgrxykwfwyb602pcGeRoKxjYcu1pJRs9IeD5YiQK3mMQbd6V/DIcMbsmp2Y7IljnBAU9SCtx8DlLge7rFOvnMWFxxeuUsDKjFy CbaQ8j3/ I9vOVoPFNChPCiTs1Fv+VjjD/YcqNnHApLXKZc8OsloUzDxSqr6qscLRY31AsgHbZmfUziE+HhI9zGT/TFHrOfeB6+qXlFm88P+YIqbGCJhohcAcfPJU7Jh9O4UubfhcOt0PNCCtpLyHIpZAm88jWY6BXRkFEjVKIzYHKiNooGNy6nYJw29nBA3zQB3o09ybeJiewEGFesSRLmaA25c4YD6kDsnubuE41kYvbJ4XN2E0wOTdULiVv2NgWlY5I62cpzTloaVE907clAPunrLHr2zl2R17VpapsKBoRNmW/4CJDmlgYtV1nownvR+1A5lXk93JfFNqlcy350b0kBHx1Nxsu7JkghwFeg8m8eoIWwlSBII4= Sender: owner-linux-mm@kvack.org Precedence: bulk X-Loop: owner-majordomo@kvack.org List-ID: List-Subscribe: List-Unsubscribe: On Thu, Jul 30, 2026 at 07:31:21AM -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. > > When CONFIG_DEBUG_KMEMLEAK_AUTO_SCAN and CONFIG_DEBUG_KMEMLEAK_VERBOSE are > both enabled, the scan thread runs periodically and the user has opted into > detailed leak reporting, so a second confirming scan happens on its own. > > Default min_unref_scans to 2 in that configuration to suppress transient > false positives. > > Keep the default at 1 otherwise, where a manually triggered scan is > expected to report immediately. The value stays writable through the module > parameter. > > Signed-off-by: Breno Leitao Acked-by: Catalin Marinas