[PATCH AUTOSEL 5.16 003/217] Bluetooth: Fix memory leak of hci device

From: Sasha Levin
Date: Mon Jan 17 2022 - 21:20:03 EST


From: Wei Yongjun <weiyongjun1@xxxxxxxxxx>

[ Upstream commit 75d9b8559ac36e059238ee4f8e33cd86086586ba ]

Fault injection test reported memory leak of hci device as follows:

unreferenced object 0xffff88800b858000 (size 8192):
comm "kworker/0:2", pid 167, jiffies 4294955747 (age 557.148s)
hex dump (first 32 bytes):
00 00 00 00 00 00 00 00 00 00 00 00 00 00 00 00 ................
00 00 00 00 00 00 00 00 00 00 00 00 ad 4e ad de .............N..
backtrace:
[<0000000070eb1059>] kmem_cache_alloc_trace mm/slub.c:3208
[<00000000015eb521>] hci_alloc_dev_priv include/linux/slab.h:591
[<00000000dcfc1e21>] bpa10x_probe include/net/bluetooth/hci_core.h:1240
[<000000005d3028c7>] usb_probe_interface drivers/usb/core/driver.c:397
[<00000000cbac9243>] really_probe drivers/base/dd.c:517
[<0000000024cab3f0>] __driver_probe_device drivers/base/dd.c:751
[<00000000202135cb>] driver_probe_device drivers/base/dd.c:782
[<000000000761f2bc>] __device_attach_driver drivers/base/dd.c:899
[<00000000f7d63134>] bus_for_each_drv drivers/base/bus.c:427
[<00000000c9551f0b>] __device_attach drivers/base/dd.c:971
[<000000007f79bd16>] bus_probe_device drivers/base/bus.c:487
[<000000007bb8b95a>] device_add drivers/base/core.c:3364
[<000000009564d9ea>] usb_set_configuration drivers/usb/core/message.c:2171
[<00000000e4657087>] usb_generic_driver_probe drivers/usb/core/generic.c:239
[<0000000071ede518>] usb_probe_device drivers/usb/core/driver.c:294
[<00000000cbac9243>] really_probe drivers/base/dd.c:517

hci_alloc_dev() do not init the device's flag. And hci_free_dev()
using put_device() to free the memory allocated for this device,
but it calls just put_device(dev) only in case of HCI_UNREGISTER
flag is set, So any error handing before hci_register_dev() success
will cause memory leak.

To avoid this behaviour we can using kfree() to release dev before
hci_register_dev() success.

Signed-off-by: Wei Yongjun <weiyongjun1@xxxxxxxxxx>
Signed-off-by: Marcel Holtmann <marcel@xxxxxxxxxxxx>
Signed-off-by: Sasha Levin <sashal@xxxxxxxxxx>
---
net/bluetooth/hci_sysfs.c | 2 ++
1 file changed, 2 insertions(+)

diff --git a/net/bluetooth/hci_sysfs.c b/net/bluetooth/hci_sysfs.c
index 7827639ecf5c3..4e3e0451b08c1 100644
--- a/net/bluetooth/hci_sysfs.c
+++ b/net/bluetooth/hci_sysfs.c
@@ -86,6 +86,8 @@ static void bt_host_release(struct device *dev)

if (hci_dev_test_flag(hdev, HCI_UNREGISTER))
hci_release_dev(hdev);
+ else
+ kfree(hdev);
module_put(THIS_MODULE);
}

--
2.34.1