From: wang, biao <biao.w...@intel.com>
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.
for example:
cpu 0 cpu 1
usbnet_suspend
usbnet_bh { ->usbnet_terminate_urbs {
dev->wait = &unlink_wakeup;
while(....){..}//break
if(dev->wait) is true
dev->wait=NULL
}//unlink_wakeup is invalid
__wake_up(dev->wait)//garbage value
}
the race is due to unprotection of dev->wait, so this patch involves a
spinlock to avoid it.
Signed-off-by: wang, biao <biao.w...@intel.com>
Signed-off-by: Zhang, Di <di.zh...@intel.com>
---
drivers/net/usb/usbnet.c | 16 ++++++++++++++--
1 files changed, 14 insertions(+), 2 deletions(-)
diff --git a/drivers/net/usb/usbnet.c b/drivers/net/usb/usbnet.c
index 90a429b..f7df1af 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 spinlock_t dev_wait_lock = __SPIN_LOCK_UNLOCKED(dev_wait_lock);
module_param (msg_level, int, 0);
MODULE_PARM_DESC (msg_level, "Override default message level");
@@ -764,11 +765,14 @@ static void usbnet_terminate_urbs(struct usbnet *dev)
DECLARE_WAIT_QUEUE_HEAD_ONSTACK(unlink_wakeup);
DECLARE_WAITQUEUE(wait, current);
int temp;
+ unsigned long flags;
/* ensure there are no more active urbs */
add_wait_queue(&unlink_wakeup, &wait);
set_current_state(TASK_UNINTERRUPTIBLE);
+ spin_lock_irqsave(&dev_wait_lock, flags);
dev->wait = &unlink_wakeup;
+ spin_unlock_irqrestore(&dev_wait_lock, flags);
temp = unlink_urbs(dev, &dev->txq) +
unlink_urbs(dev, &dev->rxq);
@@ -782,7 +786,9 @@ static void usbnet_terminate_urbs(struct usbnet *dev)
"waited for %d urb completions\n", temp);
}
set_current_state(TASK_RUNNING);
+ spin_lock_irqsave(&dev_wait_lock, flags);
dev->wait = NULL;
+ spin_unlock_irqrestore(&dev_wait_lock, flags);
remove_wait_queue(&unlink_wakeup, &wait);
}
@@ -1424,6 +1430,7 @@ static void usbnet_bh (unsigned long param)
struct usbnet *dev = (struct usbnet *) param;
struct sk_buff *skb;
struct skb_data *entry;
+ unsigned long flags;
while ((skb = skb_dequeue (&dev->done))) {
entry = (struct skb_data *) skb->cb;
@@ -1447,13 +1454,18 @@ static void usbnet_bh (unsigned long param)
clear_bit(EVENT_RX_KILL, &dev->flags);
// waiting for all pending urbs to complete?
+ spin_lock_irqsave(&dev_wait_lock, flags);
if (dev->wait) {
if ((dev->txq.qlen + dev->rxq.qlen + dev->done.qlen) == 0) {
- wake_up (dev->wait);
+ wake_up(dev->wait);
}
+ spin_unlock_irqrestore(&dev_wait_lock, flags);
+ return;
+ }
+ spin_unlock_irqrestore(&dev_wait_lock, flags);
// or are we maybe short a few urbs?
- } else if (netif_running (dev->net) &&
+ if (netif_running(dev->net) &&
netif_device_present (dev->net) &&
netif_carrier_ok(dev->net) &&
!timer_pending (&dev->delay) &&
--
1.7.0.4
--
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