From 0845735e2d1e4c177076d4bc2d841d9f77e95131 Mon Sep 17 00:00:00 2001
From: Felix Fietkau <nbd@openwrt.org>
Date: Wed, 20 Oct 2010 15:59:28 +0200
Subject: [PATCH] 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>
---
 drivers/net/wireless/ath/ath9k/main.c | 3 +++
 1 file changed, 3 insertions(+)

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);
 
-- 
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