This is a note to let you know that I've just added the patch titled

usb: hcd: initialize hcd->flags to 0 when rm hcd

to the 4.4-stable tree which can be found at: http://www.kernel.org/git/?p=linux/kernel/git/stable/stable-queue.git%3Ba=su...

The filename of the patch is: usb-hcd-initialize-hcd-flags-to-0-when-rm-hcd.patch and it can be found in the queue-4.4 subdirectory.

If you, or anyone else, feels it should not be added to the stable tree, please let stable@vger.kernel.org know about it.

From foo@baz Thu Nov 9 18:22:51 CET 2017

From: William wu wulf@rock-chips.com Date: Fri, 13 Jan 2017 11:04:22 +0800 Subject: usb: hcd: initialize hcd->flags to 0 when rm hcd

From: William wu wulf@rock-chips.com

[ Upstream commit 76b8db0d480e8045e1a1902fc9ab143b3b9ef115 ]

On some platforms(e.g. rk3399 board), we can call hcd_add/remove consecutively without calling usb_put_hcd/usb_create_hcd in between, so hcd->flags can be stale.

If the HC dies due to whatever reason then without this patch we get the below error on next hcd_add.

[173.296154] xhci-hcd xhci-hcd.2.auto: HC died; cleaning up [173.296209] xhci-hcd xhci-hcd.2.auto: xHCI Host Controller [173.296762] xhci-hcd xhci-hcd.2.auto: new USB bus registered, assigned bus number 6 [173.296931] usb usb6: We don't know the algorithms for LPM for this host, disabling LPM. [173.297179] usb usb6: New USB device found, idVendor=1d6b, idProduct=0003 [173.297203] usb usb6: New USB device strings: Mfr=3, Product=2, SerialNumber=1 [173.297222] usb usb6: Product: xHCI Host Controller [173.297240] usb usb6: Manufacturer: Linux 4.4.21 xhci-hcd [173.297257] usb usb6: SerialNumber: xhci-hcd.2.auto [173.298680] hub 6-0:1.0: USB hub found [173.298749] hub 6-0:1.0: 1 port detected [173.299382] rockchip-dwc3 usb@fe800000: USB HOST connected [173.395418] hub 5-0:1.0: activate --> -19 [173.603447] irq 228: nobody cared (try booting with the "irqpoll" option) [173.603493] CPU: 0 PID: 0 Comm: swapper/0 Not tainted 4.4.21 #9 [173.603513] Hardware name: Google Kevin (DT) [173.603531] Call trace: [173.603568] [<ffffffc0002087dc>] dump_backtrace+0x0/0x160 [173.603596] [<ffffffc00020895c>] show_stack+0x20/0x28 [173.603623] [<ffffffc0004b28a8>] dump_stack+0x90/0xb0 [173.603650] [<ffffffc00027347c>] __report_bad_irq+0x48/0xe8 [173.603674] [<ffffffc0002737cc>] note_interrupt+0x1e8/0x28c [173.603698] [<ffffffc000270a38>] handle_irq_event_percpu+0x1d4/0x25c [173.603722] [<ffffffc000270b0c>] handle_irq_event+0x4c/0x7c [173.603748] [<ffffffc00027456c>] handle_fasteoi_irq+0xb4/0x124 [173.603777] [<ffffffc00026fe3c>] generic_handle_irq+0x30/0x44 [173.603804] [<ffffffc0002701a8>] __handle_domain_irq+0x90/0xbc [173.603827] [<ffffffc0002006f4>] gic_handle_irq+0xcc/0x188 ... [173.604500] [<ffffffc000203700>] el1_irq+0x80/0xf8 [173.604530] [<ffffffc000261388>] cpu_startup_entry+0x38/0x3cc [173.604558] [<ffffffc00090f7d8>] rest_init+0x8c/0x94 [173.604585] [<ffffffc000e009ac>] start_kernel+0x3d0/0x3fc [173.604607] [<0000000000b16000>] 0xb16000 [173.604622] handlers: [173.604648] [<ffffffc000642084>] usb_hcd_irq [173.604673] Disabling IRQ #228

Signed-off-by: William wu wulf@rock-chips.com Acked-by: Roger Quadros rogerq@ti.com Signed-off-by: Greg Kroah-Hartman gregkh@linuxfoundation.org Signed-off-by: Sasha Levin alexander.levin@verizon.com Signed-off-by: Greg Kroah-Hartman gregkh@linuxfoundation.org --- drivers/usb/core/hcd.c | 1 + 1 file changed, 1 insertion(+)

--- a/drivers/usb/core/hcd.c +++ b/drivers/usb/core/hcd.c @@ -2997,6 +2997,7 @@ void usb_remove_hcd(struct usb_hcd *hcd) }

usb_put_invalidate_rhdev(hcd); + hcd->flags = 0; } EXPORT_SYMBOL_GPL(usb_remove_hcd);

Patches currently in stable-queue which might be from wulf@rock-chips.com are

queue-4.4/usb-hcd-initialize-hcd-flags-to-0-when-rm-hcd.patch