BMC/Intel-BMC/linux.git/drivers/net/usb/usbnet.c, branch dev-4.3

usbnet: Fix a race between usbnet_stop() and the BH

2015-09-08T20:17:43+00:00

The race may happen when a device (e.g. YOTA 4G LTE Modem) is unplugged while the system is downloading a large file from the Net. Hardware breakpoints and Kprobes with delays were used to confirm that the race does actually happen. The race is on skb_queue ('next' pointer) between usbnet_stop() and rx_complete(), which, in turn, calls usbnet_bh(). Here is a part of the call stack with the code where the changes to the queue happen. The line numbers are for the kernel 4.1.0: *0 __skb_unlink (skbuff.h:1517) prev->next = next; *1 defer_bh (usbnet.c:430) spin_lock_irqsave(&list->lock, flags); old_state = entry->state; entry->state = state; __skb_unlink(skb, list); spin_unlock(&list->lock); spin_lock(&dev->done.lock); __skb_queue_tail(&dev->done, skb); if (dev->done.qlen == 1) tasklet_schedule(&dev->bh); spin_unlock_irqrestore(&dev->done.lock, flags); *2 rx_complete (usbnet.c:640) state = defer_bh(dev, skb, &dev->rxq, state); At the same time, the following code repeatedly checks if the queue is empty and reads these values concurrently with the above changes: *0 usbnet_terminate_urbs (usbnet.c:765) /* maybe wait for deletions to finish. */ while (!skb_queue_empty(&dev->rxq) && !skb_queue_empty(&dev->txq) && !skb_queue_empty(&dev->done)) { schedule_timeout(msecs_to_jiffies(UNLINK_TIMEOUT_MS)); set_current_state(TASK_UNINTERRUPTIBLE); netif_dbg(dev, ifdown, dev->net, "waited for %d urb completions\n", temp); } *1 usbnet_stop (usbnet.c:806) if (!(info->flags & FLAG_AVOID_UNLINK_URBS)) usbnet_terminate_urbs(dev); As a result, it is possible, for example, that the skb is removed from dev->rxq by __skb_unlink() before the check "!skb_queue_empty(&dev->rxq)" in usbnet_terminate_urbs() is made. It is also possible in this case that the skb is added to dev->done queue after "!skb_queue_empty(&dev->done)" is checked. So usbnet_terminate_urbs() may stop waiting and return while dev->done queue still has an item. Locking in defer_bh() and usbnet_terminate_urbs() was revisited to avoid this race. Signed-off-by: Eugene Shatokhin Reviewed-by: Bjørn Mork Acked-by: Oliver Neukum Signed-off-by: David S. Miller

usbnet: Get EVENT_NO_RUNTIME_PM bit before it is cleared

2015-08-26T02:44:13+00:00

It is needed to check EVENT_NO_RUNTIME_PM bit of dev->flags in usbnet_stop(), but its value should be read before it is cleared when dev->flags is set to 0. The problem was spotted and the fix was provided by Oliver Neukum . Signed-off-by: Eugene Shatokhin Acked-by: Oliver Neukum Signed-off-by: David S. Miller

usbnet: avoid integer overflow in start_xmit

2015-05-09T20:46:18+00:00

transfer_buffer_length is of type u32. It's therefore wrong to assign it to a signed integer. This patch avoids the overflow. It's worth noting that entry->length here is a long; perhaps it would be beneficial at somepoint to change this to be unsigned as well, if nothing else relies on its signedness for error conditions or the like. Signed-off-by: Jason A. Donenfeld Signed-off-by: David S. Miller

usbnet: rename work handler

2015-04-09T18:37:59+00:00

"kevent" is an extremely generic name that causes trouble if debugging for work queues is used. So change it to something clear. Signed-off-by: Oliver Neukum Signed-off-by: David S. Miller

usbnet: Fix tx_bytes statistic running backward in cdc_ncm

2015-03-29T19:06:45+00:00

cdc_ncm disagrees with usbnet about how much framing overhead should be counted in the tx_bytes statistics, and tries 'fix' this by decrementing tx_bytes on the transmit path. But statistics must never be decremented except due to roll-over; this will thoroughly confuse user-space. Also, tx_bytes is only incremented by usbnet in the completion path. Fix this by requiring drivers that set FLAG_MULTI_FRAME to set a tx_bytes delta along with the tx_packets count. Fixes: beeecd42c3b4 ("net: cdc_ncm/cdc_mbim: adding NCM protocol statistics") Signed-off-by: Ben Hutchings Signed-off-by: Bjørn Mork

usbnet: Fix tx_packets stat for FLAG_MULTI_FRAME drivers

2015-03-29T19:06:43+00:00

Currently the usbnet core does not update the tx_packets statistic for drivers with FLAG_MULTI_PACKET and there is no hook in the TX completion path where they could do this. cdc_ncm and dependent drivers are bumping tx_packets stat on the transmit path while asix and sr9800 aren't updating it at all. Add a packet count in struct skb_data so these drivers can fill it in, initialise it to 1 for other drivers, and add the packet count to the tx_packets statistic on completion. Signed-off-by: Ben Hutchings Tested-by: Bjørn Mork Signed-off-by: David S. Miller

usbnet: re-use native hex2bin()

2015-01-25T08:09:41+00:00

Call hex2bin() library function, instead of doing conversion here. Signed-off-by: Andy Shevchenko Acked-by: Oliver Neukum Signed-off-by: David S. Miller

usbnet: add a callback for set_rx_mode

2014-10-28T21:26:19+00:00

To delegate promiscuous mode and multicast filtering to the subdriver. Signed-off-by: Olivier Blin Signed-off-by: David S. Miller

usb: hub: rename khubd to hub_wq in documentation and comments

2014-09-24T05:33:19+00:00

USB hub has started to use a workqueue instead of kthread. Let's update the documentation and comments here and there. This patch mostly just replaces "khubd" with "hub_wq". There are only few exceptions where the whole sentence was updated. These more complicated changes can be found in the following files: Documentation/usb/hotplug.txt drivers/net/usb/usbnet.c drivers/usb/core/hcd.c drivers/usb/host/ohci-hcd.c drivers/usb/host/xhci.c Signed-off-by: Petr Mladek Acked-by: Alan Stern Signed-off-by: Greg Kroah-Hartman

cdc_subset: deal with a device that needs reset for timeout

2014-08-02T22:44:18+00:00

This device needs to be reset to recover from a timeout. Unfortunately this can be handled only at the level of the subdrivers. Signed-off-by: Oliver Neukum Signed-off-by: David S. Miller