Re: [PATCH] misc/uss720: fix memory leak in uss720_probe

Greg KH
2021-05-14T11:14:45Z

On Fri, May 14, 2021 at 07:03:17PM +0800, Dongliang Mu wrote:
> uss720_probe forgets to decrease the refcount of usbdev in uss720_probe.
> Fix this by decreasing the refcount of usbdev by usb_put_dev.
>
> BUG: memory leak
> unreferenced object 0xffff888101113800 (size 2048):
> comm "kworker/0:1", pid 7, jiffies 4294956777 (age 28.870s)
> hex dump (first 32 bytes):
> ff ff ff ff 31 00 00 00 00 00 00 00 00 00 00 00 ....1...........
> 00 00 00 00 00 00 00 00 00 00 00 00 03 00 00 00 ................
> backtrace:
> [<ffffffff82b8e822>] kmalloc include/linux/slab.h:554 [inline]
> [<ffffffff82b8e822>] kzalloc include/linux/slab.h:684 [inline]
> [<ffffffff82b8e822>] usb_alloc_dev+0x32/0x450 drivers/usb/core/usb.c:582
> [<ffffffff82b98441>] hub_port_connect drivers/usb/core/hub.c:5129 [inline]
> [<ffffffff82b98441>] hub_port_connect_change drivers/usb/core/hub.c:5363 [inline]
> [<ffffffff82b98441>] port_event drivers/usb/core/hub.c:5509 [inline]
> [<ffffffff82b98441>] hub_event+0x1171/0x20c0 drivers/usb/core/hub.c:5591
> [<ffffffff81259229>] process_one_work+0x2c9/0x600 kernel/workqueue.c:2275
> [<ffffffff81259b19>] worker_thread+0x59/0x5d0 kernel/workqueue.c:2421
> [<ffffffff81261228>] kthread+0x178/0x1b0 kernel/kthread.c:292
> [<ffffffff8100227f>] ret_from_fork+0x1f/0x30 arch/x86/entry/entry_64.S:294
>
> Reported-by: syzbot+636c58f40a86b4a879e7@syzkaller.appspotmail.com
> Signed-off-by: Dongliang Mu <mudongliangabcd@gmail.com>
> ---
> drivers/usb/misc/uss720.c | 1 +
> 1 file changed, 1 insertion(+)
>
> diff --git a/drivers/usb/misc/uss720.c b/drivers/usb/misc/uss720.c
> index b5d661644263..748139d26263 100644
> --- a/drivers/usb/misc/uss720.c
> +++ b/drivers/usb/misc/uss720.c
> @@ -736,6 +736,7 @@ static int uss720_probe(struct usb_interface *intf,
> parport_announce_port(pp);
>
> usb_set_intfdata(intf, pp);
> + usb_put_dev(usbdev);
> return 0;
>
> probe_abort:
> --
> 2.25.1
>

Nice catch!