From nobody Wed Dec 17 07:31:33 2025 Received: from invmail4.hynix.com (exvmail4.hynix.com [166.125.252.92]) by smtp.subspace.kernel.org (Postfix) with ESMTP id ED10A4C83; Wed, 16 Apr 2025 11:31:39 +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=1744803104; cv=none; b=o9/uzhjgfONMXOJaAh9pG84NjG/dgQMCtft5kxKeZOP7qw+jZgFy5CwayJjvGJHDnVxmIbqLlg6T3USkSR37lNA8L6wjK9pAIwvZYrp7067SElkQ5rr9Sor1ZvsET+H0ed7o2mvqzQzfyJsq75kfbCuAKC/saf8zWqRZhwY5qI8= ARC-Message-Signature: i=1; a=rsa-sha256; d=subspace.kernel.org; s=arc-20240116; t=1744803104; c=relaxed/simple; bh=DojL5Wj/u5Iox+MiFuP7XiWOZUQZruqf2pUSCmkY9+0=; h=From:To:Cc:Subject:Date:Message-ID:In-Reply-To:References: MIME-Version; b=XFPkyt6JsUrREEeJdMKoFagbyOfrKmwAtmf1ZR2mCzzDVKIqIBmdspJRO+TVY8B6GJFZ49hdqV55D8RAm3NydQdWjORtQPZDSw/C5XcKierFtkOrPOoQlQWuhqrecUjpXdIx+lLQj91tK/o68MLK/yGtiqlV0XjKFfyjnHcRmWs= 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-0d-67ff95176253 From: Rakie Kim To: akpm@linux-foundation.org Cc: gourry@gourry.net, 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, osalvador@suse.de, kernel_team@skhynix.com, honggyu.kim@sk.com, yunjeong.mun@sk.com, rakie.kim@sk.com Subject: [PATCH v8 1/3] mm/mempolicy: Fix memory leaks in weighted interleave sysfs Date: Wed, 16 Apr 2025 20:31:19 +0900 Message-ID: <20250416113123.629-2-rakie.kim@sk.com> X-Mailer: git-send-email 2.48.1.windows.1 In-Reply-To: <20250416113123.629-1-rakie.kim@sk.com> References: <20250416113123.629-1-rakie.kim@sk.com> Precedence: bulk X-Mailing-List: linux-kernel@vger.kernel.org List-Id: List-Subscribe: List-Unsubscribe: MIME-Version: 1.0 Content-Transfer-Encoding: quoted-printable X-Brightmail-Tracker: H4sIAAAAAAAAA+NgFnrBLMWRmVeSWpSXmKPExsXC9ZZnka741P/pBvdmaVnMWb+GzWL61AuM Fl/X/2K2+Hn3OLvFqoXX2CyOb53HbnF+1ikWi8u75rBZ3Fvzn9XizLQii9VrMhy4PXbOusvu 0d12md2j5chbVo/Fe14yeWz6NInd48SM3yweOx9aerzfd5XNY/Ppao/Pm+QCuKK4bFJSczLL Uov07RK4Ml58mMVa8EK74k5XaAPjF+UuRk4OCQETicfTHjPC2Md/PmbqYuTgYBNQkji2NwYk LCIgKzH173mWLkYuDmaBx0wSj56/AKsXFgiWaNvaxw5iswioSmxqWAhm8woYS0x//w1qpqZE w6V7TCA2J9D8k5MWgcWFgGq2vprHCFEvKHFy5hMWEJtZQF6ieetsZpBlEgLv2SROzT0JNUhS 4uCKGywTGPlnIemZhaRnASPTKkahzLyy3MTMHBO9jMq8zAq95PzcTYzA8F9W+yd6B+OnC8GH GAU4GJV4eCPi/6ULsSaWFVfmHmKU4GBWEuE9Zw4U4k1JrKxKLcqPLyrNSS0+xCjNwaIkzmv0 rTxFSCA9sSQ1OzW1ILUIJsvEwSnVwOjzn2lrLu+yiDePOwt2J/Q05aQcCN6+51vVrL8JphNc P4hvD9hzzVqvUO2EzvWucyzzPm026rq7NueaT6jD63WnHOJ9/oifOXCLz8gip/vI3D3dZ+1/ HD17pGJBWVi00mMOVYPaV1fORP2olmipsLljFGPJfWHrgWd56avPTXu80KTEo37V+tlKLMUZ iYZazEXFiQAz67gYewIAAA== X-Brightmail-Tracker: H4sIAAAAAAAAA+NgFnrELMWRmVeSWpSXmKPExsXCNUNNS1d86v90g+/bJC3mrF/DZjF96gVG i6/rfzFb/Lx7nN3i87PXzBarFl5jszi+dR67xeG5J1ktzs86xWJxedccNot7a/6zWpyZVmRx 6NpzVovVazIsfm9bwebA77Fz1l12j+62y+weLUfesnos3vOSyWPTp0nsHidm/Gbx2PnQ0uP9 vqtsHt9ue3gsfvGByWPz6WqPz5vkAniiuGxSUnMyy1KL9O0SuDJefJjFWvBCu+JOV2gD4xfl LkZODgkBE4njPx8zdTFycLAJKEkc2xsDEhYRkJWY+vc8SxcjFwezwGMmiUfPXzCCJIQFgiXa tvaxg9gsAqoSmxoWgtm8AsYS099/Y4SYqSnRcOkeE4jNCTT/5KRFYHEhoJqtr+YxQtQLSpyc +YQFxGYWkJdo3jqbeQIjzywkqVlIUgsYmVYximTmleUmZuaY6hVnZ1TmZVboJefnbmIEhvyy 2j8TdzB+uex+iFGAg1GJhzci/l+6EGtiWXFl7iFGCQ5mJRHec+ZAId6UxMqq1KL8+KLSnNTi Q4zSHCxK4rxe4akJQgLpiSWp2ampBalFMFkmDk6pBsbiLeevx04Qatgp/LVyVXtPUFWpioFG R+3dJ3ZCnQxvQkvvHXktW64o38wXecWS72XRi5yPiy2vuKWpNUpJSa1wTngj/n91SJjsgfx/ D68cnfJAld23acLUZbeMF7T8253T02b8xERRXuzIquCd76YaWEWXslqoJ2d67mefs/NqTDGj 8/HVB5VYijMSDbWYi4oTAbmV3J91AgAA X-CFilter-Loop: Reflected Content-Type: text/plain; charset="utf-8" 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 proper `kobject_del()` and `kobject_put()` sequences, ensuring correct teardown and preventing memory leaks. By explicitly calling `kobject_del()` before `kobject_put()`, the release function is now invoked safely, and internal sysfs state is correctly cleaned up. This guarantees that the memory associated with the kobject is fully released and avoids resource leaks, thereby improving system stability. Additionally, sysfs_remove_file() is no longer called from the release function to avoid accessing invalid sysfs state after kobject_del(). All attribute removals are now done before kobject_del(), preventing WARN_ON() in kernfs and ensuring safe and consistent cleanup of sysfs entries. Fixes: dce41f5ae253 ("mm/mempolicy: implement the sysfs-based weighted_inte= rleave interface") Signed-off-by: Rakie Kim Reviewed-by: Gregory Price Reviewed-by: Joshua Hahn Reviewed-by: Jonathan Cameron Reviewed-by: Dan Williams --- mm/mempolicy.c | 111 +++++++++++++++++++++++++++---------------------- 1 file changed, 61 insertions(+), 50 deletions(-) diff --git a/mm/mempolicy.c b/mm/mempolicy.c index b28a1e6ae096..dcf03c389b51 100644 --- a/mm/mempolicy.c +++ b/mm/mempolicy.c @@ -3463,8 +3463,8 @@ static ssize_t node_store(struct kobject *kobj, struc= t kobj_attribute *attr, =20 static struct iw_node_attr **node_attrs; =20 -static void sysfs_wi_node_release(struct iw_node_attr *node_attr, - struct kobject *parent) +static void sysfs_wi_node_delete(struct iw_node_attr *node_attr, + struct kobject *parent) { if (!node_attr) return; @@ -3473,18 +3473,41 @@ static void sysfs_wi_node_release(struct iw_node_at= tr *node_attr, kfree(node_attr); } =20 -static void sysfs_wi_release(struct kobject *wi_kobj) +static void sysfs_wi_node_delete_all(struct kobject *wi_kobj) { - int i; + int nid; =20 - for (i =3D 0; i < nr_node_ids; i++) - sysfs_wi_node_release(node_attrs[i], wi_kobj); - kobject_put(wi_kobj); + for (nid =3D 0; nid < nr_node_ids; nid++) + sysfs_wi_node_delete(node_attrs[nid], wi_kobj); +} + +static void iw_table_free(void) +{ + u8 *old; + + mutex_lock(&iw_table_lock); + old =3D rcu_dereference_protected(iw_table, + lockdep_is_held(&iw_table_lock)); + if (old) { + rcu_assign_pointer(iw_table, NULL); + mutex_unlock(&iw_table_lock); + + synchronize_rcu(); + kfree(old); + } else + mutex_unlock(&iw_table_lock); +} + +static void wi_kobj_release(struct kobject *wi_kobj) +{ + iw_table_free(); + kfree(node_attrs); + kfree(wi_kobj); } =20 static const struct kobj_type wi_ktype =3D { .sysfs_ops =3D &kobj_sysfs_ops, - .release =3D sysfs_wi_release, + .release =3D wi_kobj_release, }; =20 static int add_weight_node(int nid, struct kobject *wi_kobj) @@ -3525,41 +3548,42 @@ static int add_weighted_interleave_group(struct kob= ject *root_kobj) struct kobject *wi_kobj; int nid, err; =20 + node_attrs =3D kcalloc(nr_node_ids, sizeof(struct iw_node_attr *), + GFP_KERNEL); + if (!node_attrs) + return -ENOMEM; + wi_kobj =3D kzalloc(sizeof(struct kobject), GFP_KERNEL); - if (!wi_kobj) + if (!wi_kobj) { + kfree(node_attrs); return -ENOMEM; + } =20 err =3D kobject_init_and_add(wi_kobj, &wi_ktype, root_kobj, "weighted_interleave"); - if (err) { - kfree(wi_kobj); - return err; - } + if (err) + goto err_put_kobj; =20 for_each_node_state(nid, N_POSSIBLE) { err =3D add_weight_node(nid, wi_kobj); if (err) { pr_err("failed to add sysfs [node%d]\n", nid); - break; + goto err_cleanup_kobj; } } - if (err) - kobject_put(wi_kobj); + return 0; + +err_cleanup_kobj: + sysfs_wi_node_delete_all(wi_kobj); + kobject_del(wi_kobj); +err_put_kobj: + kobject_put(wi_kobj); + return err; } =20 static void mempolicy_kobj_release(struct kobject *kobj) { - u8 *old; - - mutex_lock(&iw_table_lock); - old =3D rcu_dereference_protected(iw_table, - lockdep_is_held(&iw_table_lock)); - rcu_assign_pointer(iw_table, NULL); - mutex_unlock(&iw_table_lock); - synchronize_rcu(); - kfree(old); - kfree(node_attrs); kfree(kobj); } =20 @@ -3573,37 +3597,24 @@ static int __init mempolicy_sysfs_init(void) static struct kobject *mempolicy_kobj; =20 mempolicy_kobj =3D kzalloc(sizeof(*mempolicy_kobj), GFP_KERNEL); - if (!mempolicy_kobj) { - err =3D -ENOMEM; - goto err_out; - } - - node_attrs =3D kcalloc(nr_node_ids, sizeof(struct iw_node_attr *), - GFP_KERNEL); - if (!node_attrs) { - err =3D -ENOMEM; - goto mempol_out; - } + if (!mempolicy_kobj) + return -ENOMEM; =20 err =3D kobject_init_and_add(mempolicy_kobj, &mempolicy_ktype, mm_kobj, "mempolicy"); if (err) - goto node_out; + goto err_put_kobj; =20 err =3D 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_del_kobj; =20 - 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"); + return 0; + +err_del_kobj: + kobject_del(mempolicy_kobj); +err_put_kobj: + kobject_put(mempolicy_kobj); return err; } =20 --=20 2.34.1