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 <khoroshi...@ispras.ru>
---
 drivers/net/wireless/ath/ath9k/hif_usb.c | 9 ++++++---
 1 file changed, 6 insertions(+), 3 deletions(-)

diff --git a/drivers/net/wireless/ath/ath9k/hif_usb.c 
b/drivers/net/wireless/ath/ath9k/hif_usb.c
index f5dda84..fcd9aa5 100644
--- a/drivers/net/wireless/ath/ath9k/hif_usb.c
+++ b/drivers/net/wireless/ath/ath9k/hif_usb.c
@@ -1076,7 +1076,7 @@ static void ath9k_hif_usb_firmware_fail(struct 
hif_device_usb *hif_dev)
        struct device *dev = &hif_dev->udev->dev;
        struct device *parent = dev->parent;
 
-       complete(&hif_dev->fw_done);
+       complete_all(&hif_dev->fw_done);
 
        if (parent)
                device_lock(parent);
@@ -1125,7 +1125,7 @@ static void ath9k_hif_usb_firmware_cb(const struct 
firmware *fw, void *context)
 
        release_firmware(fw);
        hif_dev->flags |= HIF_USB_READY;
-       complete(&hif_dev->fw_done);
+       complete_all(&hif_dev->fw_done);
 
        return;
 
@@ -1310,7 +1310,10 @@ static int ath9k_hif_usb_suspend(struct usb_interface 
*interface,
        if (!(hif_dev->flags & HIF_USB_START))
                ath9k_htc_suspend(hif_dev->htc_handle);
 
-       ath9k_hif_usb_dealloc_urbs(hif_dev);
+       wait_for_completion(&hif_dev->fw_done);
+
+       if (hif_dev->flags & HIF_USB_READY)
+               ath9k_hif_usb_dealloc_urbs(hif_dev);
 
        return 0;
 }
-- 
1.8.1.2

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