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b=AlK0mVoTY6sneItpiY2CtIJnhxTr/lvHMD13iW6tiNvxXPs+jwfVUykRN9ByK5wfc x1jZs9BXUP1WYdd9JRQzSwrTLjtN9sF4j08XOiPmZV1qdecrzfpDztzLJEbWdeWlcI 9YqZE6P74LaE6M9o4dnLB5UhXfAQxd6wu5QCl62B1i8h/UP7mYAmCnzT0heXKDXzqF redVhJNHObmk+V3Zo50atu/aJtEMnZ4d9C7PFHpeKWONUwl7749P7QrFbf8ERJMT0o ObuDkq0todeVlkaKawJCxaeFrbgaLpprLKJ+Sqqs1V+ZwcgbwMQCtQVcK9Fwg8BAbz v7ZevBSKHMFtw== From: SJ Park To: Cc: SJ Park , stable@vger.kernel.org, Andrew Morton , Ravi Jonnalagadda , damon@lists.linux.dev, linux-kernel@vger.kernel.org, linux-mm@kvack.org Subject: [RFC PATCH v1.2 3/4] mm/damon/core: copy nid for eligible_mem_bp damos quota goal commit Date: Thu, 27 Aug 2026 18:46:57 -0700 Message-ID: <20260828014659.121058-4-sj@kernel.org> X-Mailer: git-send-email 2.47.3 In-Reply-To: <20260828014659.121058-1-sj@kernel.org> References: <20260828014659.121058-1-sj@kernel.org> MIME-Version: 1.0 Content-Transfer-Encoding: 8bit X-Rspamd-Server: rspam05 X-Rspamd-Queue-Id: DEF4E1A0008 X-Stat-Signature: 6dmnf3arq8i86omiuty7namze81utyyo X-Rspam-User: X-HE-Tag: 1787881629-666543 X-HE-Meta: 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 gjZd8zJu JYepS25v5p6bS+uPi42A/kX7/zybrIhjbjtx0kCs1wDXlHw7rILr1imCZ+3V8AowMzfOg8fet1iqlUZDWGCLXxdHmqm6NBURIaisUUHtOh2xpbv8UbBYqCynOY2w+sIj1uTdnxWdeam42fodn8PMyoRwwc8soMWvea+eKptcz7R5YnPzkyE5547gvqEvO6V5I3NwAm/fkGDSD1Iv74opWQOrH2ifl/t+PQxuWEpRUCeGygmDTkEO9hgFkONFaUHcO1HKTUvs1uXYIxmNNcGQZpKL2hM2nBxneUnD8EdEwFeuAgVY6OMimijDLa9sXGgQF7M/AYwilyJyQo90wyMDVTgmxJjM679Mp7rESPfZ5jY3z6rwFrCg8mvfIkm+I33nzIExMI5Tx+YxkilfZR1aO5mXiAGMF6F6Jw1mt Sender: owner-linux-mm@kvack.org Precedence: bulk X-Loop: owner-majordomo@kvack.org List-ID: List-Subscribe: List-Unsubscribe: damos_commit_quota_goal_union() is not updating the ->nid union field when the goal metric is DAMOS_QUITA_NODE_ELIGIBLE_MEM_BP. Hence, if a DAMOS quota goal of the type is online committed in a way that it will reuse other quota goal's memory space, the new goal will work with a garbage nid value. As a result, the DAMOS scheme can show unexpected aggressiveness. Do the update. The user impact is not catastrophic. No leak or crash happens. Doing the quota goal online commit that can reproduce the issue is expected to be not common. This issue was not found by real users but the AI review. That said, the issue can reliably be reproduced. This issue was discovered [1] by Sashiko. [1] https://lore.kkernel.org/20260827045035.94611-1-sj@kernel.org Fixes: 9138e27a3bc3 ("mm/damon: add node_eligible_mem_bp goal metric") Cc: # 7.2.x Signed-off-by: SJ Park --- mm/damon/core.c | 3 +++ 1 file changed, 3 insertions(+) diff --git a/mm/damon/core.c b/mm/damon/core.c index f7e66898aeb84..ce649553d768d 100644 --- a/mm/damon/core.c +++ b/mm/damon/core.c @@ -1136,6 +1136,9 @@ static void damos_commit_quota_goal_union( dst->nid = src->nid; dst->memcg_id = src->memcg_id; break; + case DAMOS_QUOTA_NODE_ELIGIBLE_MEM_BP: + dst->nid = src->nid; + break; default: break; } -- 2.47.3