linux-kernel - [PATCH v2] bus: fix possible memory leak in bus

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Message-ID: <20221017121110.4188783-1-yangyingliang@huawei.com>
Date:   Mon, 17 Oct 2022 20:11:10 +0800
From:   Yang Yingliang <yangyingliang@...wei.com>
To:     <linux-kernel@...r.kernel.org>
CC:     <gregkh@...uxfoundation.org>, <rafael@...nel.org>
Subject: [PATCH v2] bus: fix possible memory leak in bus_register()

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

unreferenced object 0xffff888103bddb68 (size 8):
  comm "systemd-udevd", pid 341, jiffies 4294903262 (age 42.212s)
  hex dump (first 8 bytes):
    65 64 61 63 00 00 00 00                          edac....
  backtrace:
    [<000000009e31d566>] __kmalloc_track_caller+0x1ae/0x320
    [<00000000e4cfd8de>] kstrdup+0x3a/0x70
    [<000000003d0ec369>] kstrdup_const+0x68/0x80
    [<000000008e5c3b20>] kvasprintf_const+0x10b/0x190
    [<00000000b9a945aa>] kobject_set_name_vargs+0x56/0x150
    [<000000000df9278c>] kobject_set_name+0xab/0xe0
    [<00000000f51dc49f>] bus_register+0x132/0x350
    [<000000007d91c2e5>] subsys_register+0x23/0x220

Fixes: 1da177e4c3f4 ("Linux-2.6.12-rc2")
Signed-off-by: Yang Yingliang <yangyingliang@...wei.com>
---
v1 -> v2:
  Update commit message and add fix tag.
---
 drivers/base/bus.c | 4 +++-
 1 file changed, 3 insertions(+), 1 deletion(-)

diff --git a/drivers/base/bus.c b/drivers/base/bus.c
index 7ca47e5b3c1f..301b5330f9d8 100644
--- a/drivers/base/bus.c
+++ b/drivers/base/bus.c
@@ -804,8 +804,10 @@ int bus_register(struct bus_type *bus)
 	priv->drivers_autoprobe = 1;
 
 	retval = kset_register(&priv->subsys);
-	if (retval)
+	if (retval) {
+		kset_put(&priv->subsys);
 		goto out;
+	}
 
 	retval = bus_create_file(bus, &bus_attr_uevent);
 	if (retval)
-- 
2.25.1