With commit 69bec7259853 ("USB: core: let USB device know device node"), the port1 argument of usb_alloc_dev() gets overwritten as follows: ... usb_alloc_dev(..., unsigned port1) { ... if (!parent->parent) { port1 = usb_hcd_find_raw_port_number(..., port1); } ... } Later on, this now overwritten port1 gets assigned to ->portnum: dev->portnum = port1; However, since xhci_find_raw_port_number() isn't idempotent, the aforementioned commit causes a number of KASAN splats like the following: BUG: KASAN: slab-out-of-bounds in xhci_find_raw_port_number+0x98/0x170 at addr ffff8801d9311670 Read of size 8 by task kworker/2:1/87 [...] Workqueue: usb_hub_wq hub_event 0000000000000188 000000005814b877 ffff8800cba17588 ffffffff8191447e 0000000041b58ab3 ffffffff82a03209 ffffffff819143a2 ffffffff82a252f4 ffff8801d93115e0 0000000000000188 ffff8801d9311628 ffff8800cba17588 Call Trace: [<ffffffff8191447e>] dump_stack+0xdc/0x15e [<ffffffff819143a2>] ? _atomic_dec_and_lock+0xa2/0xa2 [<ffffffff814e2cd1>] ? print_section+0x61/0xb0 [<ffffffff814e4939>] print_trailer+0x179/0x2c0 [<ffffffff814f0d84>] object_err+0x34/0x40 [<ffffffff814f4388>] kasan_report_error+0x2f8/0x8b0 [<ffffffff814eb91e>] ? __slab_alloc+0x5e/0x90 [<ffffffff812178c0>] ? __lock_is_held+0x90/0x130 [<ffffffff814f5091>] kasan_report+0x71/0xa0 [<ffffffff814ec082>] ? kmem_cache_alloc_trace+0x212/0x560 [<ffffffff81d99468>] ? xhci_find_raw_port_number+0x98/0x170 [<ffffffff814f33d4>] __asan_load8+0x64/0x70 [<ffffffff81d99468>] xhci_find_raw_port_number+0x98/0x170 [<ffffffff81db0105>] xhci_setup_addressable_virt_dev+0x235/0xa10 [<ffffffff81d9ea51>] xhci_setup_device+0x3c1/0x1430 [<ffffffff8121cddd>] ? trace_hardirqs_on+0xd/0x10 [<ffffffff81d9fac0>] ? xhci_setup_device+0x1430/0x1430 [<ffffffff81d9fad3>] xhci_address_device+0x13/0x20 [<ffffffff81d2081a>] hub_port_init+0x55a/0x1550 [<ffffffff81d28705>] hub_event+0xef5/0x24d0 [<ffffffff81d27810>] ? hub_port_debounce+0x2f0/0x2f0 [<ffffffff8195e1ee>] ? debug_object_deactivate+0x1be/0x270 [<ffffffff81210203>] ? print_rt_rq+0x53/0x2d0 [<ffffffff8121657d>] ? trace_hardirqs_off+0xd/0x10 [<ffffffff8226acfb>] ? _raw_spin_unlock_irqrestore+0x5b/0x60 [<ffffffff81250000>] ? irq_domain_set_hwirq_and_chip+0x30/0xb0 [<ffffffff81256339>] ? debug_lockdep_rcu_enabled+0x39/0x40 [<ffffffff812178c0>] ? __lock_is_held+0x90/0x130 [<ffffffff81196877>] process_one_work+0x567/0xec0 [...] Afterwards, xhci reports some functional errors: xhci_hcd 0000:00:14.0: ERROR: unexpected setup address command completion code 0x11. xhci_hcd 0000:00:14.0: ERROR: unexpected setup address command completion code 0x11. usb 4-3: device not accepting address 2, error -22 Fix this by not overwriting the port1 argument in usb_alloc_dev(), but storing the raw port number as required by OF in an additional variable, raw_port. Fixes: 69bec7259853 ("USB: core: let USB device know device node") Signed-off-by: Nicolai Stange <nicstange@xxxxxxxxx> --- Applicable to linux-next-20160317 Changes to v1: - Initialize raw_port with port1 drivers/usb/core/usb.c | 5 +++-- 1 file changed, 3 insertions(+), 2 deletions(-) diff --git a/drivers/usb/core/usb.c b/drivers/usb/core/usb.c index ffa5cf1..dcb85e3 100644 --- a/drivers/usb/core/usb.c +++ b/drivers/usb/core/usb.c @@ -424,6 +424,7 @@ struct usb_device *usb_alloc_dev(struct usb_device *parent, struct usb_device *dev; struct usb_hcd *usb_hcd = bus_to_hcd(bus); unsigned root_hub = 0; + unsigned raw_port = port1; dev = kzalloc(sizeof(*dev), GFP_KERNEL); if (!dev) @@ -498,11 +499,11 @@ struct usb_device *usb_alloc_dev(struct usb_device *parent, if (!parent->parent) { /* device under root hub's port */ - port1 = usb_hcd_find_raw_port_number(usb_hcd, + raw_port = usb_hcd_find_raw_port_number(usb_hcd, port1); } dev->dev.of_node = usb_of_get_child_node(parent->dev.of_node, - port1); + raw_port); /* hub driver sets up TT records */ } -- 2.7.2 -- 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