[PATCH ath-next] ath9k: delete channel-context timers on deinit

[Rosen Penev <rosenp@gmail.com>]

ath9k_deinit_channel_context() cancels chanctx_work but does not delete
the offchannel and sched timers set up by ath9k_init_channel_context().
If either timer fires after deinit (e.g. during driver unload or
suspend), it accesses sc->sc_ah which may already be freed by
ath9k_hw_deinit(), causing a use-after-free.

Delete both timers with timer_delete_sync() before cancelling the work
item.

Assisted-by: opencode:big-pickle
Signed-off-by: Rosen Penev <rosenp@gmail.com>
---
 drivers/net/wireless/ath/ath9k/channel.c | 2 ++
 1 file changed, 2 insertions(+)

diff --git a/drivers/net/wireless/ath/ath9k/channel.c b/drivers/net/wireless/ath/ath9k/channel.c
index 8b27d8cc086a..92241c24a0a4 100644
--- a/drivers/net/wireless/ath/ath9k/channel.c
+++ b/drivers/net/wireless/ath/ath9k/channel.c
@@ -1363,6 +1363,8 @@ void ath9k_init_channel_context(struct ath_softc *sc)
 
 void ath9k_deinit_channel_context(struct ath_softc *sc)
 {
+	timer_delete_sync(&sc->sched.timer);
+	timer_delete_sync(&sc->offchannel.timer);
 	cancel_work_sync(&sc->chanctx_work);
 }
 
-- 
2.55.0