From: Gregory Herrero <gregory.herrero@intel.com>
Date: Tue, 22 Sep 2015 13:16:53 +0000 (+0200)
Subject: usb: dwc2: host: kill remaining urbs using -ECONNRESET status
X-Git-Tag: v4.4-rc1~127^2~12^2~58
X-Git-Url: http://review.tizen.org/git/?a=commitdiff_plain;h=2e84da6e340a652e942c3513703020976b28190b;p=platform%2Fkernel%2Flinux-exynos.git

usb: dwc2: host: kill remaining urbs using -ECONNRESET status

On a disconnect, dwc2 will kill all remaining urbs from qh list.
urbs are given back to hcd with -ETIMEDOUT status.
Some usb device driver, like mass storage, will unlink all urbs
using usb_hcd_unlink_urb when receiving a negative status different
from -ECONNRESET.
The following flow will then happen:
dwc2_hcd_disconnect()
-> dwc2_kill_all_urbs() try to kill first pending urb.
-> dwc2_host_complete(-ETIMEDOUT)
-> usb_hcd_giveback_urb(-ETIMEDOUT)
-> sg_complete()
-> usb_unlink_urb()
	-> usb_put_dev(urb->dev)
-> dwc2_kill_all_urbs() try to kill next pending urb.
-> dwc2_host_complete(-ETIMEDOUT)
-> usb_hcd_giveback_urb(-ETIMEDOUT)
-> NULL pointer dereferencing because urb->dev has been freed for all
urbs of this device.

The root cause of this NULL pointer is to call call usb_unlink_urb()
while we are killing all urbs. To avoid this return urb with
-ECONNRESET status

This issue usually happens while removing mass storage device during
transfer.

Signed-off-by: Gregory Herrero <gregory.herrero@intel.com>
Signed-off-by: Mian Yousaf Kaukab <yousaf.kaukab@intel.com>
Tested-by: Robert Baldyga <r.baldyga@samsung.com>
Tested-by: Dinh Nguyen <dinguyen@opensource.altera.com>
Tested-by: John Youn <johnyoun@synopsys.com>
Acked-by: John Youn <johnyoun@synopsys.com>
Signed-off-by: Felipe Balbi <balbi@ti.com>
---

diff --git a/drivers/usb/dwc2/hcd.c b/drivers/usb/dwc2/hcd.c
index 397bb7d..15a1e62 100644
--- a/drivers/usb/dwc2/hcd.c
+++ b/drivers/usb/dwc2/hcd.c
@@ -134,7 +134,7 @@ static void dwc2_kill_urbs_in_qh_list(struct dwc2_hsotg *hsotg,
 	list_for_each_entry_safe(qh, qh_tmp, qh_list, qh_list_entry) {
 		list_for_each_entry_safe(qtd, qtd_tmp, &qh->qtd_list,
 					 qtd_list_entry) {
-			dwc2_host_complete(hsotg, qtd, -ETIMEDOUT);
+			dwc2_host_complete(hsotg, qtd, -ECONNRESET);
 			dwc2_hcd_qtd_unlink_and_free(hsotg, qtd, qh);
 		}
 	}