syzbot is reporting that del_timer_sync() is called from mwifiex_usb_cleanup_tx_aggr() from mwifiex_unregister_dev() without checking timer_setup() from mwifiex_usb_tx_init() was called [1]. Ganapathi Bhat proposed a possibly cleaner fix, but it seems that that fix was forgotten [2]. "grep -FrB1 'del_timer' drivers/ | grep -FA1 '.function)'" says that currently there are 28 locations which call del_timer[_sync]() only if that timer's function field was initialized (because timer_setup() sets that timer's function field). Therefore, let's use same approach here. [1] https://syzkaller.appspot.com/bug?id=26525f643f454dd7be0078423e3cdb0d57744959 [2] https://lkml.kernel.org/r/CA+ASDXMHt2gq9Hy+iP_BYkWXsSreWdp3_bAfMkNcuqJ3K+-jbQ@xxxxxxxxxxxxxx Reported-by: syzbot <syzbot+dc4127f950da51639216@xxxxxxxxxxxxxxxxxxxxxxxxx> Cc: Ganapathi Bhat <ganapathi.bhat@xxxxxxx> Cc: Brian Norris <briannorris@xxxxxxxxxxxx> Signed-off-by: Tetsuo Handa <penguin-kernel@xxxxxxxxxxxxxxxxxxx> --- drivers/net/wireless/marvell/mwifiex/usb.c | 3 ++- 1 file changed, 2 insertions(+), 1 deletion(-) diff --git a/drivers/net/wireless/marvell/mwifiex/usb.c b/drivers/net/wireless/marvell/mwifiex/usb.c index 6f3cfde4654c..426e39d4ccf0 100644 --- a/drivers/net/wireless/marvell/mwifiex/usb.c +++ b/drivers/net/wireless/marvell/mwifiex/usb.c @@ -1353,7 +1353,8 @@ static void mwifiex_usb_cleanup_tx_aggr(struct mwifiex_adapter *adapter) skb_dequeue(&port->tx_aggr.aggr_list))) mwifiex_write_data_complete(adapter, skb_tmp, 0, -1); - del_timer_sync(&port->tx_aggr.timer_cnxt.hold_timer); + if (port->tx_aggr.timer_cnxt.hold_timer.function) + del_timer_sync(&port->tx_aggr.timer_cnxt.hold_timer); port->tx_aggr.timer_cnxt.is_hold_timer_set = false; port->tx_aggr.timer_cnxt.hold_tmo_msecs = 0; } -- 2.18.4
