Hi Ganapathi, On Fri, Jun 01, 2018 at 04:11:20PM +0530, Ganapathi Bhat wrote: > 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. > > Signed-off-by: Brian Norris <[email protected]>
^^ I'm not sure if that line is quite accurate. While I nearly spelled out what the patch would look like, you wrote it. Anyway, patch seems good to me, assuming it tests out OK for you: Reviewed-by: Brian Norris <[email protected]> and if Kalle hasn't applied this yet, an alternative to Signed-off-by: Suggested-by: Brian Norris <[email protected]> > Signed-off-by: Ganapathi Bhat <[email protected]> > --- > drivers/net/wireless/marvell/mwifiex/usb.c | 4 ++-- > 1 file changed, 2 insertions(+), 2 deletions(-) > > diff --git a/drivers/net/wireless/marvell/mwifiex/usb.c > b/drivers/net/wireless/marvell/mwifiex/usb.c > index bc475b8..88f4c89 100644 > --- a/drivers/net/wireless/marvell/mwifiex/usb.c > +++ b/drivers/net/wireless/marvell/mwifiex/usb.c > @@ -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; > -- > 1.9.1 >
