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mwifiex: handle race during mwifiex_usb_disconnect

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Race condition is observed during rmmod of mwifiex_usb:

1. The rmmod thread will call mwifiex_usb_disconnect(), download
   SHUTDOWN command and do wait_event_interruptible_timeout(),
   waiting for response.

2. The main thread will handle the response and will do a
   wake_up_interruptible(), unblocking rmmod thread.

3. On getting unblocked, rmmod thread  will make rx_cmd.urb = NULL in
   mwifiex_usb_free().

4. The main thread will try to resubmit rx_cmd.urb in
   mwifiex_usb_submit_rx_urb(), which is NULL.

To fix this, move mwifiex_usb_free() from mwifiex_usb_disconnect
to mwifiex_unregister_dev(). Function mwifiex_unregister_dev() is
called after flushing the command and RX work queues.

Suggested-by: Brian Norris <briannorris@chromium.org>
Signed-off-by: Ganapathi Bhat <gbhat@marvell.com>
Reviewed-by: Brian Norris <briannorris@chromium.org>
Signed-off-by: Kalle Valo <kvalo@codeaurora.org>
This commit is contained in:
Ganapathi Bhat 2018-06-01 16:11:20 +05:30 committed by Kalle Valo
parent 7e58e741c0
commit f8c095f679
1 changed files with 2 additions and 2 deletions
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4
drivers/net/wireless/marvell/mwifiex/usb.c
View File

@ -644,8 +644,6 @@ static void mwifiex_usb_disconnect(struct usb_interface *intf)
MWIFIEX_FUNC_SHUTDOWN);
}
mwifiex_usb_free(card);
mwifiex_dbg(adapter, FATAL,
"%s: removing card\n", __func__);
mwifiex_remove_card(adapter);
@ -1353,6 +1351,8 @@ static void mwifiex_unregister_dev(struct mwifiex_adapter *adapter)
{
struct usb_card_rec *card = (struct usb_card_rec *)adapter->card;
mwifiex_usb_free(card);
mwifiex_usb_cleanup_tx_aggr(adapter);
card->adapter = NULL;