>From ee48b3736d437af79d4fe858cdf64f241c76c339 Mon Sep 17 00:00:00 2001 From: "Du, Changbin" <changbinx.du@xxxxxxxxx> Date: Wed, 18 Dec 2013 16:47:21 +0800 Subject: [PATCH] usb/core: fix NULL pointer dereference in recursively_mark_NOTATTACHED usb_hub_to_struct_hub() can return NULL if the hub without active configuration. So the result must be checked. BUG: unable to handle kernel NULL pointer dereference at 0000015c IP: [<c16d5fb0>] recursively_mark_NOTATTACHED+0x20/0x60 Call Trace: [<c16d5fc4>] recursively_mark_NOTATTACHED+0x34/0x60 [<c16d5fc4>] recursively_mark_NOTATTACHED+0x34/0x60 [<c16d5fc4>] recursively_mark_NOTATTACHED+0x34/0x60 [<c16d5fc4>] recursively_mark_NOTATTACHED+0x34/0x60 [<c16d6082>] usb_set_device_state+0x92/0x120 [<c16d862b>] usb_disconnect+0x2b/0x1a0 [<c16dd4c0>] usb_remove_hcd+0xb0/0x160 [<c19ca846>] ? _raw_spin_unlock_irqrestore+0x26/0x50 [<c1704efc>] ehci_mid_remove+0x1c/0x30 [<c1704f26>] ehci_mid_stop_host+0x16/0x30 [<c16f7698>] penwell_otg_work+0xd28/0x3520 [<c19c945b>] ? __schedule+0x39b/0x7f0 [<c19cdb9d>] ? sub_preempt_count+0x3d/0x50 [<c125e97d>] process_one_work+0x11d/0x3d0 [<c19c7f4d>] ? mutex_unlock+0xd/0x10 [<c125e0e5>] ? manage_workers.isra.24+0x1b5/0x270 [<c125f009>] worker_thread+0xf9/0x320 [<c19ca846>] ? _raw_spin_unlock_irqrestore+0x26/0x50 [<c125ef10>] ? rescuer_thread+0x2b0/0x2b0 [<c1264ac4>] kthread+0x94/0xa0 [<c19d0f77>] ret_from_kernel_thread+0x1b/0x28 [<c1264a30>] ? kthread_create_on_node+0xc0/0xc0 Signed-off-by: Du, Changbin <changbinx.du@xxxxxxxxx> --- drivers/usb/core/hub.c | 8 +++++--- 1 file changed, 5 insertions(+), 3 deletions(-) diff --git a/drivers/usb/core/hub.c b/drivers/usb/core/hub.c index bd9dc35..01a1fe6 100644 --- a/drivers/usb/core/hub.c +++ b/drivers/usb/core/hub.c @@ -1870,9 +1870,11 @@ static void recursively_mark_NOTATTACHED(struct usb_device *udev) struct usb_hub *hub = usb_hub_to_struct_hub(udev); int i; - for (i = 0; i < udev->maxchild; ++i) { - if (hub->ports[i]->child) - recursively_mark_NOTATTACHED(hub->ports[i]->child); + if (hub) { + for (i = 0; i < udev->maxchild; ++i) { + if (hub->ports[i]->child) + recursively_mark_NOTATTACHED(hub->ports[i]->child); + } } if (udev->state == USB_STATE_SUSPENDED) udev->active_duration -= jiffies; -- 1.8.3.2 -- To unsubscribe from this list: send the line "unsubscribe linux-usb" in the body of a message to majordomo@xxxxxxxxxxxxxxx More majordomo info at http://vger.kernel.org/majordomo-info.html