From mboxrd@z Thu Jan 1 00:00:00 1970 From: Ryusuke Konishi Subject: [PATCH 2/6] nilfs2: fix NULL pointer in nilfs_##name##_attr_release Date: Wed, 7 Jul 2021 18:48:22 +0900 Message-ID: <1625651306-10829-3-git-send-email-konishi.ryusuke@gmail.com> References: <1625651306-10829-1-git-send-email-konishi.ryusuke@gmail.com> Return-path: DKIM-Signature: v=1; a=rsa-sha256; c=relaxed/relaxed; d=gmail.com; s=20161025; h=from:to:cc:subject:date:message-id:in-reply-to:references; bh=nDphwP7rk7MVmmwi41RmQwruvzgJtyrk5UC8vBfmCnU=; b=HAwqV7SRwg6Bmoo+IUskz5DjJH8OArmVvNbXrAsMJFs1WKQPXL4k8BMKwnvr8tsADx V+Kss4NWm4EsIyxBLRXjn20jxwQac+LwPilRbQCebnzRO9fHHDPUfsOLIyd1aflsfhrY eZRG9VycHCBnh9ASsKcssnV5YuYaHu7v5YQ9E0AL7uLvzx/E3KFR4DhrMCg7dAm/GuNX XSFQYJF47N/D9cKiDGVJEzWca8GP3OU8YxzWzS9DKK9tR7P0gc+uvIeEXzxjB/J1O3W5 J7Zj9lYBjV0FGeERQcv0rBKI2/E6tv32w3NdOFSSr+kxAI7duSNB5bg/mAKgPGnfaSjh LJYA== In-Reply-To: <1625651306-10829-1-git-send-email-konishi.ryusuke@gmail.com> List-ID: MIME-Version: 1.0 Content-Type: text/plain; charset="us-ascii" Content-Transfer-Encoding: 7bit To: Andrew Morton Cc: linux-nilfs , LKML From: Nanyong Sun In nilfs_##name##_attr_release, kobj->parent should not be referenced because it is a NULL pointer. The release() method of kobject is always called in kobject_put(kobj), in the implementation of kobject_put(), the kobj->parent will be assigned as NULL before call the release() method. So just use kobj to get the subgroups, which is more efficient and can fix a NULL pointer reference problem. Link: https://lkml.kernel.org/r/20210629022556.3985106-3-sunnanyong@huawei.com Signed-off-by: Nanyong Sun Signed-off-by: Ryusuke Konishi --- fs/nilfs2/sysfs.c | 8 +++----- 1 file changed, 3 insertions(+), 5 deletions(-) diff --git a/fs/nilfs2/sysfs.c b/fs/nilfs2/sysfs.c index b6a48492fed2..43f660beb9b4 100644 --- a/fs/nilfs2/sysfs.c +++ b/fs/nilfs2/sysfs.c @@ -64,11 +64,9 @@ #define NILFS_DEV_INT_GROUP_TYPE(name, parent_name) \ static void nilfs_##name##_attr_release(struct kobject *kobj) \ { \ - struct nilfs_sysfs_##parent_name##_subgroups *subgroups; \ - struct the_nilfs *nilfs = container_of(kobj->parent, \ - struct the_nilfs, \ - ns_##parent_name##_kobj); \ - subgroups = nilfs->ns_##parent_name##_subgroups; \ + struct nilfs_sysfs_##parent_name##_subgroups *subgroups = container_of(kobj, \ + struct nilfs_sysfs_##parent_name##_subgroups, \ + sg_##name##_kobj); \ complete(&subgroups->sg_##name##_kobj_unregister); \ } \ static struct kobj_type nilfs_##name##_ktype = { \ -- 1.8.3.1