ath9k: fix crash in ath_update_survey_stats

If ah->curchan is uninitialized, the channel index is bogus, which leads
to invalid memory access when the cycle counters are updated.

Signed-off-by: Felix Fietkau <nbd@openwrt.org>
Signed-off-by: John W. Linville <linville@tuxdriver.com>

1 files changed, 3 insertions, 0 deletions

diff --git a/drivers/net/wireless/ath/ath9k/main.c b/drivers/net/wireless/ath/ath9k/main.c
index 3ff0e476c2b3..9679b3191975 100644
--- a/drivers/net/wireless/ath/ath9k/main.c
+++ b/drivers/net/wireless/ath/ath9k/main.c
@@ -182,6 +182,9 @@ static void ath_update_survey_stats(struct ath_softc *sc)
         struct ath_cycle_counters *cc = &common->cc_survey;
         unsigned int div = common->clockrate * 1000;
 
+        if (!ah->curchan)
+                return;
+
         if (ah->power_mode == ATH9K_PM_AWAKE)
                 ath_hw_cycle_counters_update(common);