linux-kernel - [PATCH 07/11] f2fs: fix possible memory leak in f2fs_init

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Date:   Fri, 21 Oct 2022 10:20:58 +0800
From:   Yang Yingliang <yangyingliang@...wei.com>
To:     <linux-kernel@...r.kernel.org>, <qemu-devel@...gnu.org>,
        <linux-f2fs-devel@...ts.sourceforge.net>,
        <linux-erofs@...ts.ozlabs.org>, <ocfs2-devel@....oracle.com>,
        <linux-mtd@...ts.infradead.org>, <amd-gfx@...ts.freedesktop.org>
CC:     <gregkh@...uxfoundation.org>, <rafael@...nel.org>, <somlo@....edu>,
        <mst@...hat.com>, <jaegeuk@...nel.org>, <chao@...nel.org>,
        <hsiangkao@...ux.alibaba.com>, <huangjianan@...o.com>,
        <mark@...heh.com>, <jlbec@...lplan.org>,
        <joseph.qi@...ux.alibaba.com>, <akpm@...ux-foundation.org>,
        <alexander.deucher@....com>, <luben.tuikov@....com>,
        <richard@....at>, <liushixin2@...wei.com>
Subject: [PATCH 07/11] f2fs: fix possible memory leak in f2fs_init_sysfs()

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 0xffff888101b7cc80 (size 8):
  comm "modprobe", pid 252, jiffies 4294691378 (age 31.760s)
  hex dump (first 8 bytes):
    66 32 66 73 00 88 ff ff                          f2fs....
  backtrace:
    [<000000001db5b408>] __kmalloc_node_track_caller+0x44/0x1b0
    [<000000002783a073>] kstrdup+0x3a/0x70
    [<00000000ead2b281>] kstrdup_const+0x63/0x80
    [<000000003e5cf8f7>] kvasprintf_const+0x149/0x180
    [<00000000c4d949ff>] kobject_set_name_vargs+0x56/0x150
    [<0000000044611660>] kobject_set_name+0xab/0xe0

Fixes: bf9e697ecd42 ("f2fs: expose features to sysfs entry")
Signed-off-by: Yang Yingliang <yangyingliang@...wei.com>
Reviewed-by: Chao Yu <chao@...nel.org>
---
 fs/f2fs/sysfs.c | 4 +++-
 1 file changed, 3 insertions(+), 1 deletion(-)

diff --git a/fs/f2fs/sysfs.c b/fs/f2fs/sysfs.c
index df27afd71ef4..2ef7a48967be 100644
--- a/fs/f2fs/sysfs.c
+++ b/fs/f2fs/sysfs.c
@@ -1250,8 +1250,10 @@ int __init f2fs_init_sysfs(void)
 	kobject_set_name(&f2fs_kset.kobj, "f2fs");
 	f2fs_kset.kobj.parent = fs_kobj;
 	ret = kset_register(&f2fs_kset);
-	if (ret)
+	if (ret) {
+		kset_put(&f2fs_kset);
 		return ret;
+	}
 
 	ret = kobject_init_and_add(&f2fs_feat, &f2fs_feat_ktype,
 				   NULL, "features");
-- 
2.25.1