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[173.79.56.208]) by smtp.gmail.com with ESMTPSA id 6a1803df08f44-6e8f70a44adsm85938316d6.64.2025.03.12.08.49.07 (version=TLS1_3 cipher=TLS_AES_256_GCM_SHA384 bits=256/256); Wed, 12 Mar 2025 08:49:08 -0700 (PDT) Date: Wed, 12 Mar 2025 11:49:06 -0400 From: Gregory Price 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, kernel_team@skhynix.com, honggyu.kim@sk.com, yunjeong.mun@sk.com Subject: Re: [PATCH v2 1/4] mm/mempolicy: Fix memory leaks in mempolicy_sysfs_init() Message-ID: References: <20250312075628.648-1-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-Type: text/plain; charset=us-ascii Content-Disposition: inline In-Reply-To: <20250312075628.648-1-rakie.kim@sk.com> On Wed, Mar 12, 2025 at 04:56:24PM +0900, Rakie Kim wrote: > Improper cleanup of sysfs attributes caused kobject and memory leaks when > initialization failed or nodes were removed. > > This patch ensures proper deallocation of kobjects and memory, preventing > resource leaks and improving stability. > This patch does multiple things, please split these changes into multiple patches. > Fixes: dce41f5ae253 ("mm/mempolicy: implement the sysfs-based weighted_interleave interface") > Signed-off-by: Rakie Kim > --- > mm/mempolicy.c | 29 +++++++++++++++-------------- > 1 file changed, 15 insertions(+), 14 deletions(-) > > diff --git a/mm/mempolicy.c b/mm/mempolicy.c > index bbaadbeeb291..1691748badb2 100644 > --- a/mm/mempolicy.c > +++ b/mm/mempolicy.c > @@ -3541,39 +3541,40 @@ static int __init mempolicy_sysfs_init(void) > int err; > static struct kobject *mempolicy_kobj; > > - mempolicy_kobj = kzalloc(sizeof(*mempolicy_kobj), GFP_KERNEL); > - if (!mempolicy_kobj) { > + node_attrs = kcalloc(nr_node_ids, sizeof(struct iw_node_attr *), > + GFP_KERNEL); > + if (!node_attrs) { > err = -ENOMEM; > goto err_out; > } > > - node_attrs = kcalloc(nr_node_ids, sizeof(struct iw_node_attr *), > - GFP_KERNEL); > - if (!node_attrs) { > + mempolicy_kobj = kzalloc(sizeof(*mempolicy_kobj), GFP_KERNEL); > + if (!mempolicy_kobj) { > err = -ENOMEM; > - goto mempol_out; > + goto node_out; > } It's not clear to me why you re-ordered these allocations, it seems superfluous. > > err = kobject_init_and_add(mempolicy_kobj, &mempolicy_ktype, mm_kobj, > "mempolicy"); > - if (err) > - goto node_out; > + if (err) { > + kobject_put(mempolicy_kobj); Is this correct? If kobject_init_and_add fails, from other examples we need only free the mempolicy_kobj - because it failed to initialize and therefore should not have any references. I think this causes an underflow. > + 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; > + goto err_out; > } > > - return err; > + return 0; > + Please keep functional changes and refactors separate. There's more churn in this patch than is needed to accomplish what the changelog states is the intent. > node_out: > kfree(node_attrs); > -mempol_out: > - kfree(mempolicy_kobj); > err_out: > - pr_err("failed to add mempolicy kobject to the system\n"); > + pr_err("mempolicy sysfs structure failed to initialize\n"); > return err; > + > } > > late_initcall(mempolicy_sysfs_init); > > base-commit: 80e54e84911a923c40d7bee33a34c1b4be148d7a > -- > 2.34.1 >