From: Tetsuo Handa penguin-kernel@I-love.SAKURA.ne.jp
[ Upstream commit 621a3a8b1c0ecf16e1e5667ea5756a76a082b738 ]
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=26525f643f454dd7be0078423e3cdb0d5774495... [2] https://lkml.kernel.org/r/CA+ASDXMHt2gq9Hy+iP_BYkWXsSreWdp3_bAfMkNcuqJ3K+-jb...
Reported-by: syzbot syzbot+dc4127f950da51639216@syzkaller.appspotmail.com Cc: Ganapathi Bhat ganapathi.bhat@nxp.com Cc: Brian Norris briannorris@chromium.org Signed-off-by: Tetsuo Handa penguin-kernel@I-love.SAKURA.ne.jp Reviewed-by: Brian Norris briannorris@chromium.org Acked-by: Ganapathi Bhat ganapathi.bhat@nxp.com Signed-off-by: Kalle Valo kvalo@codeaurora.org Link: https://lore.kernel.org/r/20200821082720.7716-1-penguin-kernel@I-love.SAKURA... Signed-off-by: Sasha Levin sashal@kernel.org --- 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 d445acc4786b7..2a8d40ce463d5 100644 --- a/drivers/net/wireless/marvell/mwifiex/usb.c +++ b/drivers/net/wireless/marvell/mwifiex/usb.c @@ -1355,7 +1355,8 @@ 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; }