From: wang, biao <biao.wang@xxxxxxxxx>
Date: Mon, 11 Nov 2013 10:23:40 +0800
Subject: [PATCH] usbnet: fix race condition caused spinlock bad magic issue
there is race between usbnet_terminate_urbs and usbnet_bh, when
unlink_wakeup used in usbnet_bh, it may be already freed and used by
other function as unlink_wakeup was a local var on stack.
btw, dev->wait should be judged again before use it as there is race
too.
Signed-off-by: wang, biao <biao.wang@xxxxxxxxx>
---
drivers/net/usb/usbnet.c | 7 +++++--
1 files changed, 5 insertions(+), 2 deletions(-)
diff --git a/drivers/net/usb/usbnet.c b/drivers/net/usb/usbnet.c
index 90a429b..22fc27f 100644
--- a/drivers/net/usb/usbnet.c
+++ b/drivers/net/usb/usbnet.c
@@ -86,6 +86,7 @@ static const char driver_name [] = "usbnet";
/* use ethtool to change the level for any given device */
static int msg_level = -1;
+static wait_queue_head_t unlink_wakeup;
module_param (msg_level, int, 0);
MODULE_PARM_DESC (msg_level, "Override default message level");
@@ -761,7 +762,6 @@ EXPORT_SYMBOL_GPL(usbnet_unlink_rx_urbs);
// precondition: never called in_interrupt
static void usbnet_terminate_urbs(struct usbnet *dev)
{
- DECLARE_WAIT_QUEUE_HEAD_ONSTACK(unlink_wakeup);
DECLARE_WAITQUEUE(wait, current);
int temp;
@@ -1448,8 +1448,10 @@ static void usbnet_bh (unsigned long param)
// waiting for all pending urbs to complete?
if (dev->wait) {
+ wait_queue_head_t *wait_d = dev->wait;
if ((dev->txq.qlen + dev->rxq.qlen + dev->done.qlen) == 0) {
- wake_up (dev->wait);
+ if (wait_d)
+ wake_up(wait_d);
}
// or are we maybe short a few urbs?
@@ -1602,6 +1604,7 @@ usbnet_probe (struct usb_interface *udev, const struct usb_device_id *prod)
init_timer (&dev->delay);
mutex_init (&dev->phy_mutex);
mutex_init(&dev->interrupt_mutex);
+ init_waitqueue_head(&unlink_wakeup);
dev->interrupt_count = 0;
dev->net = net;
--
1.7.0.4
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