From mboxrd@z Thu Jan 1 00:00:00 1970 Received: from smtp.kernel.org (aws-us-west-2-korg-mail-1.web.codeaurora.org [10.30.226.201]) (using TLSv1.2 with cipher ECDHE-RSA-AES256-GCM-SHA384 (256/256 bits)) (No client certificate requested) by smtp.subspace.kernel.org (Postfix) with ESMTPS id E5C671B4244 for ; Sat, 6 Sep 2025 13:48:48 +0000 (UTC) Authentication-Results: smtp.subspace.kernel.org; arc=none smtp.client-ip=10.30.226.201 ARC-Seal:i=1; a=rsa-sha256; d=subspace.kernel.org; s=arc-20240116; t=1757166529; cv=none; b=tKl+GNiXjsaOzwAxZeY2zsu6bYUdWtYKMxcjvDaUxyhGmbHNbvNI6QtyYorWA3uhAwcrG0IKMu8tZk3EoKhxhznXsRZpO6l/HJnKxYtC8FFBKEyUY4d8wtl5aHVX8dmh27d7zY9L7XaM9oRXbmSFYrYQnrnVrMUeXcfXhmVFQz4= ARC-Message-Signature:i=1; a=rsa-sha256; d=subspace.kernel.org; s=arc-20240116; t=1757166529; c=relaxed/simple; bh=7bjUI+rrm2mZGbrniHbTzQo84U0pFOpKzCBSMiTgqVY=; h=From:To:Cc:Subject:Date:Message-ID:In-Reply-To:References: MIME-Version; b=Lze1Ou/7Uw1kdqv5GyF1Jy3UBEoFwqy8xlprP4LNtF7BtkuEBob/byVVKVTT1n/13D9dW5eS8oVmvHb6ICtb2Gva0SNB0TJQNF9Fr1wpM4KEeAGGGEyH0vLhv6bLRfPsohDIxlQeTa3CN1pkuEzICwx8L94UMJVIQpfT3SYmsbw= ARC-Authentication-Results:i=1; smtp.subspace.kernel.org; dkim=pass (2048-bit key) header.d=kernel.org header.i=@kernel.org header.b=LqvX65gI; arc=none smtp.client-ip=10.30.226.201 Authentication-Results: smtp.subspace.kernel.org; dkim=pass (2048-bit key) header.d=kernel.org header.i=@kernel.org header.b="LqvX65gI" Received: by smtp.kernel.org (Postfix) with ESMTPSA id 8D89CC4CEE7; Sat, 6 Sep 2025 13:48:47 +0000 (UTC) DKIM-Signature: v=1; a=rsa-sha256; c=relaxed/simple; d=kernel.org; s=k20201202; t=1757166528; bh=7bjUI+rrm2mZGbrniHbTzQo84U0pFOpKzCBSMiTgqVY=; h=From:To:Cc:Subject:Date:In-Reply-To:References:From; b=LqvX65gIOZy/42tbfojrk+ATjUuGFNRODjZ4FnVPgxMPYuixNOJoFW7xw7Re4GMC3 Te/eiXQidXZW3r/C6TLFPXowC5Pyn4rFsj/R8LE3Ry+65fCIa764MSv4IRzB8f7Xn8 ItqSoSSOrz52IBeKbriu5p8cIBe/XfoLhOOl32kcNarLTCXbbeZrriZfA5Pt0c+Rp9 rumAfAjJ+IggzGLwTErw106o1320O9OsLDLRvowVFXofOcjJcTY92tkGfPdhsGIF7Z F/Olg9WKODfRJPhyJtIaE79MlJqjYz5GFO2oWII92OfeeQEx0ip8jhigKziaiTFimi epCwIRuH2LLAA== From: Sasha Levin To: stable@vger.kernel.org Cc: Shakeel Butt , Roman Gushchin , Johannes Weiner , Michal Hocko , Muchun Song , Andrew Morton , Sasha Levin Subject: [PATCH 6.6.y] memcg: drain obj stock on cpu hotplug teardown Date: Sat, 6 Sep 2025 09:48:45 -0400 Message-ID: <20250906134845.8414-1-sashal@kernel.org> X-Mailer: git-send-email 2.51.0 In-Reply-To: <2025032853-copy-crank-1c82@gregkh> References: <2025032853-copy-crank-1c82@gregkh> Precedence: bulk X-Mailing-List: stable@vger.kernel.org List-Id: List-Subscribe: List-Unsubscribe: MIME-Version: 1.0 Content-Transfer-Encoding: 8bit From: Shakeel Butt [ Upstream commit 9f01b4954490d4ccdbcc2b9be34a9921ceee9cbb ] Currently on cpu hotplug teardown, only memcg stock is drained but we need to drain the obj stock as well otherwise we will miss the stats accumulated on the target cpu as well as the nr_bytes cached. The stats include MEMCG_KMEM, NR_SLAB_RECLAIMABLE_B & NR_SLAB_UNRECLAIMABLE_B. In addition we are leaking reference to struct obj_cgroup object. Link: https://lkml.kernel.org/r/20250310230934.2913113-1-shakeel.butt@linux.dev Fixes: bf4f059954dc ("mm: memcg/slab: obj_cgroup API") Signed-off-by: Shakeel Butt Reviewed-by: Roman Gushchin Acked-by: Johannes Weiner Cc: Michal Hocko Cc: Muchun Song Cc: Signed-off-by: Andrew Morton Signed-off-by: Sasha Levin --- mm/memcontrol.c | 9 +++++++++ 1 file changed, 9 insertions(+) diff --git a/mm/memcontrol.c b/mm/memcontrol.c index 2d2cada8a8a4c..87e3f7761f561 100644 --- a/mm/memcontrol.c +++ b/mm/memcontrol.c @@ -2376,9 +2376,18 @@ static void drain_all_stock(struct mem_cgroup *root_memcg) static int memcg_hotplug_cpu_dead(unsigned int cpu) { struct memcg_stock_pcp *stock; + struct obj_cgroup *old; + unsigned long flags; stock = &per_cpu(memcg_stock, cpu); + + /* drain_obj_stock requires stock_lock */ + local_lock_irqsave(&memcg_stock.stock_lock, flags); + old = drain_obj_stock(stock); + local_unlock_irqrestore(&memcg_stock.stock_lock, flags); + drain_stock(stock); + obj_cgroup_put(old); return 0; } -- 2.51.0