ath9k_htc: fix data race between request_firmware_nowait() callback and suspend()
authorAlexey Khoroshilov <khoroshilov@ispras.ru>
Mon, 1 Jul 2013 20:43:42 +0000 (00:43 +0400)
committerJohn W. Linville <linville@tuxdriver.com>
Wed, 17 Jul 2013 18:34:49 +0000 (14:34 -0400)
commit9494849e53e74048ee14d512feade01db402eef7
treea7385029e763f93f3dc5d33c3ded13e3ac583470
parenta4943ccbc316fd74d3612d7a5984a91ab7e5dc8c
ath9k_htc: fix data race between request_firmware_nowait() callback and suspend()

ath9k_hif_usb_probe() requests firmware asynchronically and
there is some initialization postponed till firmware is ready.
In particular, ath9k_hif_usb_firmware_cb() callback initializes
hif_dev->tx.tx_buf and hif_dev->tx.tx_pending lists.

At the same time, ath9k_hif_usb_suspend() iterates that lists through
ath9k_hif_usb_dealloc_urbs(). If suspend happens before request_firmware_nowait()
callback is called, it can lead to oops.

Similar issue could be in ath9k_hif_usb_disconnect(), but it is prevented
using hif_dev->fw_done completion and HIF_USB_READY flag. The patch extends
this approach to suspend() as well.

Found by Linux Driver Verification project (linuxtesting.org).

Signed-off-by: Alexey Khoroshilov <khoroshilov@ispras.ru>
Signed-off-by: John W. Linville <linville@tuxdriver.com>
drivers/net/wireless/ath/ath9k/hif_usb.c