On Fri, Feb 11, 2022 at 12:17:26PM -0800, syzbot wrote: > Hello, > > syzbot found the following issue on: > > HEAD commit: dfd42facf1e4 Linux 5.17-rc3 > git tree: upstream > console output: https://syzkaller.appspot.com/x/log.txt?x=14b4ef7c700000 > kernel config: https://syzkaller.appspot.com/x/.config?x=48b71604a367da6e > dashboard link: https://syzkaller.appspot.com/bug?extid=8caaaec4e7a55d75e243 > compiler: gcc (Debian 10.2.1-6) 10.2.1 20210110, GNU ld (GNU Binutils for Debian) 2.35.2 > syz repro: https://syzkaller.appspot.com/x/repro.syz?x=1396902c700000 > C reproducer: https://syzkaller.appspot.com/x/repro.c?x=1466e662700000 > > IMPORTANT: if you fix the issue, please add the following tag to the commit: > Reported-by: syzbot+8caaaec4e7a55d75e243@xxxxxxxxxxxxxxxxxxxxxxxxx > > BUG: memory leak > unreferenced object 0xffff88810d49e800 (size 2048): > comm "kworker/1:1", pid 25, jiffies 4294954629 (age 16.460s) > 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: > [<ffffffff82c87a62>] kmalloc include/linux/slab.h:581 [inline] > [<ffffffff82c87a62>] kzalloc include/linux/slab.h:715 [inline] > [<ffffffff82c87a62>] usb_alloc_dev+0x32/0x450 drivers/usb/core/usb.c:582 > [<ffffffff82c91a47>] hub_port_connect drivers/usb/core/hub.c:5260 [inline] > [<ffffffff82c91a47>] hub_port_connect_change drivers/usb/core/hub.c:5502 [inline] > [<ffffffff82c91a47>] port_event drivers/usb/core/hub.c:5660 [inline] > [<ffffffff82c91a47>] hub_event+0x1097/0x21a0 drivers/usb/core/hub.c:5742 > [<ffffffff8126c3ef>] process_one_work+0x2bf/0x600 kernel/workqueue.c:2307 > [<ffffffff8126ccd9>] worker_thread+0x59/0x5b0 kernel/workqueue.c:2454 > [<ffffffff81276765>] kthread+0x125/0x160 kernel/kthread.c:377 > [<ffffffff810022ff>] ret_from_fork+0x1f/0x30 arch/x86/entry/entry_64.S:295 There's a refcount leak in the probe-failure path of the hid-elo driver. (You can see that this is the relevant driver in the console output.) It doesn't need the refcount anyway, because the elo_priv structure is always deallocated synchronously before the elo_remove routine returns. (Syzbot isn't always all that great at deducing where the real problem lies when something goes wrong.) Alan Stern #syz test: https://git.kernel.org/pub/scm/linux/kernel/git/torvalds/linux.git/ v5.17-rc3 Index: usb-devel/drivers/hid/hid-elo.c =================================================================== --- usb-devel.orig/drivers/hid/hid-elo.c +++ usb-devel/drivers/hid/hid-elo.c @@ -239,7 +239,7 @@ static int elo_probe(struct hid_device * INIT_DELAYED_WORK(&priv->work, elo_work); udev = interface_to_usbdev(to_usb_interface(hdev->dev.parent)); - priv->usbdev = usb_get_dev(udev); + priv->usbdev = udev; hid_set_drvdata(hdev, priv); @@ -270,8 +270,6 @@ static void elo_remove(struct hid_device { struct elo_priv *priv = hid_get_drvdata(hdev); - usb_put_dev(priv->usbdev); - hid_hw_stop(hdev); cancel_delayed_work_sync(&priv->work); kfree(priv);
