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From:   Yang Yingliang <yangyingliang@huawei.com>
To:     <linux-kernel@vger.kernel.org>, <qemu-devel@nongnu.org>,
        <linux-f2fs-devel@lists.sourceforge.net>,
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        <mst@redhat.com>, <jaegeuk@kernel.org>, <chao@kernel.org>,
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        <richard@nod.at>, <liushixin2@huawei.com>
Subject: [PATCH 08/11] erofs: fix possible memory leak in erofs_init_sysfs()
Date:   Fri, 21 Oct 2022 10:20:59 +0800
Message-ID: <20221021022102.2231464-9-yangyingliang@huawei.com>
In-Reply-To: <20221021022102.2231464-1-yangyingliang@huawei.com>
References: <20221021022102.2231464-1-yangyingliang@huawei.com>
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Precedence: bulk

Inject fault while loading module, kset_register() may fail,
if it fails, but the refcount of kobject is not decreased to
0, the name allocated in kobject_set_name() is leaked. Fix
this by calling kset_put(), so that name can be freed in
callback function kobject_cleanup().

unreferenced object 0xffff888101d228c0 (size 8):
  comm "modprobe", pid 276, jiffies 4294722700 (age 13.151s)
  hex dump (first 8 bytes):
    65 72 6f 66 73 00 ff ff                          erofs...
  backtrace:
    [<00000000e2a9a4a6>] __kmalloc_node_track_caller+0x44/0x1b0
    [<00000000b8ce02de>] kstrdup+0x3a/0x70
    [<000000004a0e01d2>] kstrdup_const+0x63/0x80
    [<00000000051b6cda>] kvasprintf_const+0x149/0x180
    [<000000004dc51dad>] kobject_set_name_vargs+0x56/0x150
    [<00000000b30f0bad>] kobject_set_name+0xab/0xe0

Fixes: 168e9a76200c ("erofs: add sysfs interface")
Signed-off-by: Yang Yingliang <yangyingliang@huawei.com>
---
 fs/erofs/sysfs.c | 4 +++-
 1 file changed, 3 insertions(+), 1 deletion(-)

diff --git a/fs/erofs/sysfs.c b/fs/erofs/sysfs.c
index 783bb7b21b51..653b35001bc5 100644
--- a/fs/erofs/sysfs.c
+++ b/fs/erofs/sysfs.c
@@ -254,8 +254,10 @@ int __init erofs_init_sysfs(void)
 	kobject_set_name(&erofs_root.kobj, "erofs");
 	erofs_root.kobj.parent = fs_kobj;
 	ret = kset_register(&erofs_root);
-	if (ret)
+	if (ret) {
+		kset_put(&erofs_root);
 		goto root_err;
+	}
 
 	ret = kobject_init_and_add(&erofs_feat, &erofs_feat_ktype,
 				   NULL, "features");
-- 
2.25.1