[PATCH 09/11] ocfs2: possible memory leak in mlog_sys_init()

Yang Yingliang
2022-10-21T02:24:22Z

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 0xffff888100da9348 (size 8):
comm "modprobe", pid 257, jiffies 4294701096 (age 33.334s)
hex dump (first 8 bytes):
6c 6f 67 6d 61 73 6b 00 logmask.
backtrace:
[<00000000306e441c>] __kmalloc_node_track_caller+0x44/0x1b0
[<000000007c491a9e>] kstrdup+0x3a/0x70
[<0000000015719a3b>] kstrdup_const+0x63/0x80
[<0000000084e458ea>] kvasprintf_const+0x149/0x180
[<0000000091302b42>] kobject_set_name_vargs+0x56/0x150
[<000000005f48eeac>] kobject_set_name+0xab/0xe0

Fixes: 34980ca8faeb ("Drivers: clean up direct setting of the name of a kset")
Signed-off-by: Yang Yingliang <yangyingliang@huawei.com>
---
fs/ocfs2/cluster/masklog.c | 7 ++++++-
1 file changed, 6 insertions(+), 1 deletion(-)

diff --git a/fs/ocfs2/cluster/masklog.c b/fs/ocfs2/cluster/masklog.c
index 563881ddbf00..7f9ba816d955 100644
--- a/fs/ocfs2/cluster/masklog.c
+++ b/fs/ocfs2/cluster/masklog.c
@@ -156,6 +156,7 @@ static struct kset mlog_kset = {
int mlog_sys_init(struct kset *o2cb_kset)
{
int i = 0;
+ int ret;

while (mlog_attrs[i].attr.mode) {
mlog_default_attrs[i] = &mlog_attrs[i].attr;
@@ -165,7 +166,11 @@ int mlog_sys_init(struct kset *o2cb_kset)

kobject_set_name(&mlog_kset.kobj, "logmask");
mlog_kset.kobj.kset = o2cb_kset;
- return kset_register(&mlog_kset);
+ ret = kset_register(&mlog_kset);
+ if (ret)
+ kset_put(&mlog_kset);
+
+ return ret;
}

void mlog_sys_shutdown(void)
--
2.25.1