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Message-Id: <1454625887-18915-28-git-send-email-kamal@canonical.com>
Date: Thu, 4 Feb 2016 14:44:10 -0800
From: Kamal Mostafa <kamal@...onical.com>
To: linux-kernel@...r.kernel.org, stable@...r.kernel.org,
kernel-team@...ts.ubuntu.com
Cc: "Du, Changbin" <changbin.du@...el.com>,
Greg Kroah-Hartman <gregkh@...uxfoundation.org>,
Kamal Mostafa <kamal@...onical.com>
Subject: [PATCH 4.2.y-ckt 27/64] usb: hub: do not clear BOS field during reset device
4.2.8-ckt4 -stable review patch. If anyone has any objections, please let me know.
---8<------------------------------------------------------------
From: "Du, Changbin" <changbin.du@...el.com>
commit d8f00cd685f5c8e0def8593e520a7fef12c22407 upstream.
In function usb_reset_and_verify_device, the old BOS descriptor may
still be used before allocating a new one. (usb_unlocked_disable_lpm
function uses it under the situation that it fails to disable lpm.)
So we cannot set the udev->bos to NULL before that, just keep what it
was. It will be overwrite when allocating a new one.
Crash log:
BUG: unable to handle kernel NULL pointer dereference at
0000000000000010
IP: [<ffffffff8171f98d>] usb_enable_link_state+0x2d/0x2f0
Call Trace:
[<ffffffff8171ed5b>] ? usb_set_lpm_timeout+0x12b/0x140
[<ffffffff8171fcd1>] usb_enable_lpm+0x81/0xa0
[<ffffffff8171fdd8>] usb_disable_lpm+0xa8/0xc0
[<ffffffff8171fe1c>] usb_unlocked_disable_lpm+0x2c/0x50
[<ffffffff81723933>] usb_reset_and_verify_device+0xc3/0x710
[<ffffffff8172c4ed>] ? usb_sg_wait+0x13d/0x190
[<ffffffff81724743>] usb_reset_device+0x133/0x280
[<ffffffff8179ccd1>] usb_stor_port_reset+0x61/0x70
[<ffffffff8179cd68>] usb_stor_invoke_transport+0x88/0x520
Signed-off-by: Du, Changbin <changbin.du@...el.com>
Signed-off-by: Greg Kroah-Hartman <gregkh@...uxfoundation.org>
Signed-off-by: Kamal Mostafa <kamal@...onical.com>
---
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 2f0fa89..252807d 100644
--- a/drivers/usb/core/hub.c
+++ b/drivers/usb/core/hub.c
@@ -5352,7 +5352,6 @@ static int usb_reset_and_verify_device(struct usb_device *udev)
}
bos = udev->bos;
- udev->bos = NULL;
for (i = 0; i < SET_CONFIG_TRIES; ++i) {
@@ -5445,8 +5444,11 @@ done:
usb_set_usb2_hardware_lpm(udev, 1);
usb_unlocked_enable_lpm(udev);
usb_enable_ltm(udev);
- usb_release_bos_descriptor(udev);
- udev->bos = bos;
+ /* release the new BOS descriptor allocated by hub_port_init() */
+ if (udev->bos != bos) {
+ usb_release_bos_descriptor(udev);
+ udev->bos = bos;
+ }
return 0;
re_enumerate:
--
1.9.1
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