From b01c9e327249e4995e5b5b6cebec14166db9c1e7 Mon Sep 17 00:00:00 2001 From: Stanislaw Gruszka Date: Wed, 10 May 2017 10:54:54 +0200 Subject: [PATCH] ath9k: check ah->curchan when updating tx power When driver fail to reset card ah->curchan value stay NULL. When later driver try to update tx power it oops by using ah->curchan (calltrace is shown below). This problem were reported at various places and for some it was fixed by making ath9k_hw_chip_reset() do not fail. I have this bug report on some oldish RHEL kernel with AR9285, however it's hard to debug where reset fail when kernel OOPS, so I think this patch should be applied. Hopefully ah->curchan is not used unconditionally on other places until is initialized on ath9k_config(). ath: phy0: Chip reset failed ath: phy0: Unable to reset hardware; reset status -22 (freq 2412 MHz) BUG: unable to handle kernel NULL pointer dereference at (null) IP: [] ath9k_hw_set_txpowerlimit+0x25/0x80 [ath9k_hw] Oops: 0000 [#1] SMP Call Trace: [] ? ath9k_cmn_update_txpow+0x1a/0x30 [ath9k_common] [] ? ath_complete_reset+0x4e/0x130 [ath9k] [] ? ath9k_start+0x127/0x1e0 [ath9k] [] ? ieee80211_do_open+0x30f/0x910 [mac80211] [] ? dev_open+0x8d/0xf0 Signed-off-by: Stanislaw Gruszka Signed-off-by: Kalle Valo --- drivers/net/wireless/ath/ath9k/common.c | 2 +- 1 file changed, 1 insertion(+), 1 deletion(-) diff --git a/drivers/net/wireless/ath/ath9k/common.c b/drivers/net/wireless/ath/ath9k/common.c index b80e08b13b74..eea2f7f23a2a 100644 --- a/drivers/net/wireless/ath/ath9k/common.c +++ b/drivers/net/wireless/ath/ath9k/common.c @@ -368,7 +368,7 @@ void ath9k_cmn_update_txpow(struct ath_hw *ah, u16 cur_txpow, { struct ath_regulatory *reg = ath9k_hw_regulatory(ah); - if (reg->power_limit != new_txpow) + if (ah->curchan && reg->power_limit != new_txpow) ath9k_hw_set_txpowerlimit(ah, new_txpow, false); /* read back in case value is clamped */ -- 2.20.1