From mboxrd@z Thu Jan 1 00:00:00 1970 Received: from invmail4.hynix.com (exvmail4.skhynix.com [166.125.252.92]) by smtp.subspace.kernel.org (Postfix) with ESMTP id 950941A3152; Thu, 20 Mar 2025 05:40:18 +0000 (UTC) Authentication-Results: smtp.subspace.kernel.org; arc=none smtp.client-ip=166.125.252.92 ARC-Seal:i=1; a=rsa-sha256; d=subspace.kernel.org; s=arc-20240116; t=1742449227; cv=none; b=Gh20z42ZXktWVd4cg9E5YC2/FWKXpuHzcabrWy92DC9uzkCmlD+ast7BEGI7xgAFwmb8GW3W1jONOTlCbvhPwvi5KVA0bJI0PYKvNRsAHTiqaX/MjsBZiGkRYSVDHFUdyj9Mi6FiFt2oaRdqb4TE7jW+Fx+RKlR28LcnyFWdLKQ= ARC-Message-Signature:i=1; a=rsa-sha256; d=subspace.kernel.org; s=arc-20240116; t=1742449227; c=relaxed/simple; bh=Upjw/yWb4OlnCEBwTmspWkyp0uJZb1mknb6860OYb5Q=; h=From:To:Cc:Subject:Date:Message-ID:In-Reply-To:References: MIME-Version; b=QLw+zzKv2oAFIw/GpUMrriKN9kZVslWHQ/W0rgu3XDyHufrinVJddz/zAzORsO7dY6HC7PnuIHyMYMPNYBzpkRhb4P9LTlFyF5E7KGLDk38v8RvHZkU2NrM6E4UmXJwJUryGjGq1M9ok1tP2Uj5JPWZJJc8l6ZqSSFjg9avwxH4= ARC-Authentication-Results:i=1; smtp.subspace.kernel.org; dmarc=none (p=none dis=none) header.from=sk.com; spf=pass smtp.mailfrom=sk.com; arc=none smtp.client-ip=166.125.252.92 Authentication-Results: smtp.subspace.kernel.org; dmarc=none (p=none dis=none) header.from=sk.com Authentication-Results: smtp.subspace.kernel.org; spf=pass smtp.mailfrom=sk.com X-AuditID: a67dfc5b-669ff7000002311f-6e-67dbaa401ae0 From: Rakie Kim To: Rakie Kim Cc: akpm@linux-foundation.org, linux-mm@kvack.org, linux-kernel@vger.kernel.org, linux-cxl@vger.kernel.org, joshua.hahnjy@gmail.com, dan.j.williams@intel.com, ying.huang@linux.alibaba.com, david@redhat.com, Jonathan.Cameron@huawei.com, kernel_team@skhynix.com, honggyu.kim@sk.com, yunjeong.mun@sk.com, gourry@gourry.net Subject: Re: [PATCH v3 1/3] mm/mempolicy: Fix memory leaks in weighted interleave sysfs Date: Thu, 20 Mar 2025 14:40:01 +0900 Message-ID: <20250320054010.914-1-rakie.kim@sk.com> X-Mailer: git-send-email 2.48.1.windows.1 In-Reply-To: <20250320041749.881-2-rakie.kim@sk.com> References: Precedence: bulk X-Mailing-List: linux-cxl@vger.kernel.org List-Id: List-Subscribe: List-Unsubscribe: MIME-Version: 1.0 Content-Transfer-Encoding: 8bit X-Brightmail-Tracker: H4sIAAAAAAAAA+NgFrrLLMWRmVeSWpSXmKPExsXC9ZZnoa7DqtvpBrOvqFnMWb+GzWL61AuM Fl/X/2K2+Hn3OLvFqoXX2CyOb53HbnF+1ikWi8u75rBZ3Fvzn9Vi9ZoMBy6PnbPusnt0t11m 92g58pbVY/Gel0wemz5NYvc4MeM3i8fOh5Ye7/ddZfP4vEkugDOKyyYlNSezLLVI3y6BK2P7 iR2sBWeUKy5t7WVsYJwi08XIySEhYCKx+eleti5GDjC7+5gBiMkmoCRxbG8MiCkioCBx6F90 FyMXB7PAdSaJsw8Ws4PEhQXCJVpniIIMYRFQlbiwfiM7iM0rYCwx7dthVojhmhINl+4xgdic QMNv9fxmA7GFBHgkXm3YzwhRLyhxcuYTFhCbWUBeonnrbGaI3tdsEvfPB0DYkhIHV9xgmcDI PwtJyywkLQsYmVYxCmXmleUmZuaY6GVU5mVW6CXn525iBAb6sto/0TsYP10IPsQowMGoxMP7 4sqtdCHWxLLiytxDjBIczEoivCIdt9OFeFMSK6tSi/Lji0pzUosPMUpzsCiJ8xp9K08REkhP LEnNTk0tSC2CyTJxcEo1MMau/qS39tH3Beb9+3Pm992MUq8NWsS4YvvhkNAddwXfCC4XuJuY 3yLZOqWuhdv+cPWS0IafdtMCjK8u6m868JqFXfruyzJlrwqnOZaCTsfufnYxTeo4UF1b5cy+ jmFWpcHV0HwxY0bOXS7FCb8CtHNcg/boTmrk+ftAU9dzzhmVoIvdr2qclFiKMxINtZiLihMB pzuOM3ACAAA= X-Brightmail-Tracker: H4sIAAAAAAAAA+NgFrrBLMWRmVeSWpSXmKPExsXCNUNNS9dh1e10g0OfZC3mrF/DZjF96gVG i6/rfzFb/Lx7nN3i87PXzBarFl5jszi+dR67xeG5J1ktzs86xWJxedccNot7a/6zWhy69pzV YvWaDIvf21awOfB57Jx1l92ju+0yu0fLkbesHov3vGTy2PRpErvHiRm/WTx2PrT0eL/vKpvH t9seHotffGDy+LxJLoA7issmJTUnsyy1SN8ugStj+4kdrAVnlCsube1lbGCcItPFyMEhIWAi 0X3MAMRkE1CSOLY3BsQUEVCQOPQvuouRi4NZ4DqTxNkHi9lB4sIC4RKtM0S7GDk5WARUJS6s 38gOYvMKGEtM+3aYFcSWENCUaLh0jwnE5gQafqvnNxuILSTAI/Fqw35GiHpBiZMzn7CA2MwC 8hLNW2czT2DkmYUkNQtJagEj0ypGkcy8stzEzBxTveLsjMq8zAq95PzcTYzA8F5W+2fiDsYv l90PMQpwMCrx8L64citdiDWxrLgy9xCjBAezkgivSMftdCHelMTKqtSi/Pii0pzU4kOM0hws SuK8XuGpCUIC6YklqdmpqQWpRTBZJg5OqQbGmrpN29YWG5x5N+WatN2C2zefqjZNF7gb+7yr TCfr7kq+BI89LE6v3nAzmapVTZ4gFyJauYzfx5Xr4QH+f1NlXe0MffLdNnz7ILswUVvPICii 6wnv7ove5nvk3EyvKVxjWpGwnN1ruf6Xd0YMT7eLN5WmJnjnL5dfnjB5Ql/zBtcfahc7dwsr sRRnJBpqMRcVJwIAooshrGsCAAA= X-CFilter-Loop: Reflected On Thu, 20 Mar 2025 13:17:46 +0900 Rakie Kim wrote: Hi Gregory I initially planned to separate this patch from the hotplug-related patch series as an independent update. However, after reviewing the code following Jonathan's suggestion to consolidate `kobject` and `node_attrs` into a single struct, I realized that most of the intended functionality for Patch 2 was already incorporated. As a result, Patch 1 now only contains the `kobject_put` fix, while the struct consolidation work has been included in Patch 2. Given the current design, it seems more natural to keep Patch 1 and Patch 2 together as part of the same patch series rather than separating them. Rakie > Memory leaks occurred when removing sysfs attributes for weighted > interleave. Improper kobject deallocation led to unreleased memory > when initialization failed or when nodes were removed. > > This patch resolves the issue by replacing unnecessary `kfree()` > calls with `kobject_put()`, ensuring proper cleanup and preventing > memory leaks. > > By correctly using `kobject_put()`, the release function now > properly deallocates memory without causing resource leaks, > thereby improving system stability. > > Fixes: dce41f5ae253 ("mm/mempolicy: implement the sysfs-based weighted_interleave interface") > Signed-off-by: Rakie Kim > --- > mm/mempolicy.c | 61 +++++++++++++++++++++++++------------------------- > 1 file changed, 31 insertions(+), 30 deletions(-) > > diff --git a/mm/mempolicy.c b/mm/mempolicy.c > index bbaadbeeb291..5950d5d5b85e 100644 > --- a/mm/mempolicy.c > +++ b/mm/mempolicy.c > @@ -3448,7 +3448,9 @@ static void sysfs_wi_release(struct kobject *wi_kobj) > > for (i = 0; i < nr_node_ids; i++) > sysfs_wi_node_release(node_attrs[i], wi_kobj); > - kobject_put(wi_kobj); > + > + kfree(node_attrs); > + kfree(wi_kobj); > } > > static const struct kobj_type wi_ktype = { > @@ -3494,15 +3496,22 @@ static int add_weighted_interleave_group(struct kobject *root_kobj) > struct kobject *wi_kobj; > int nid, err; > > - wi_kobj = kzalloc(sizeof(struct kobject), GFP_KERNEL); > - if (!wi_kobj) > + node_attrs = kcalloc(nr_node_ids, sizeof(struct iw_node_attr *), > + GFP_KERNEL); > + if (!node_attrs) > return -ENOMEM; > > + wi_kobj = kzalloc(sizeof(struct kobject), GFP_KERNEL); > + if (!wi_kobj) { > + err = -ENOMEM; > + goto node_out; > + } > + > err = kobject_init_and_add(wi_kobj, &wi_ktype, root_kobj, > "weighted_interleave"); > if (err) { > - kfree(wi_kobj); > - return err; > + kobject_put(wi_kobj); > + goto err_out; > } > > for_each_node_state(nid, N_POSSIBLE) { > @@ -3512,9 +3521,17 @@ static int add_weighted_interleave_group(struct kobject *root_kobj) > break; > } > } > - if (err) > + if (err) { > kobject_put(wi_kobj); > + goto err_out; > + } > + > return 0; > + > +node_out: > + kfree(node_attrs); > +err_out: > + return err; > } > > static void mempolicy_kobj_release(struct kobject *kobj) > @@ -3528,7 +3545,6 @@ static void mempolicy_kobj_release(struct kobject *kobj) > mutex_unlock(&iw_table_lock); > synchronize_rcu(); > kfree(old); > - kfree(node_attrs); > kfree(kobj); > } > > @@ -3542,37 +3558,22 @@ static int __init mempolicy_sysfs_init(void) > static struct kobject *mempolicy_kobj; > > mempolicy_kobj = kzalloc(sizeof(*mempolicy_kobj), GFP_KERNEL); > - if (!mempolicy_kobj) { > - err = -ENOMEM; > - goto err_out; > - } > - > - node_attrs = kcalloc(nr_node_ids, sizeof(struct iw_node_attr *), > - GFP_KERNEL); > - if (!node_attrs) { > - err = -ENOMEM; > - goto mempol_out; > - } > + if (!mempolicy_kobj) > + return -ENOMEM; > > err = kobject_init_and_add(mempolicy_kobj, &mempolicy_ktype, mm_kobj, > "mempolicy"); > if (err) > - goto node_out; > + goto err_out; > > err = add_weighted_interleave_group(mempolicy_kobj); > - if (err) { > - pr_err("mempolicy sysfs structure failed to initialize\n"); > - kobject_put(mempolicy_kobj); > - return err; > - } > + if (err) > + goto err_out; > + > + return 0; > > - return err; > -node_out: > - kfree(node_attrs); > -mempol_out: > - kfree(mempolicy_kobj); > err_out: > - pr_err("failed to add mempolicy kobject to the system\n"); > + kobject_put(mempolicy_kobj); > return err; > } > > > base-commit: 4701f33a10702d5fc577c32434eb62adde0a1ae1 > -- > 2.34.1 >