Return-path: Received: from mail.deathmatch.net ([70.167.247.36]:4681 "EHLO mail.deathmatch.net" rhost-flags-OK-OK-OK-OK) by vger.kernel.org with ESMTP id S1750860AbZCCDqt (ORCPT ); Mon, 2 Mar 2009 22:46:49 -0500 Date: Mon, 2 Mar 2009 22:46:00 -0500 From: Bob Copeland To: Pavel Roskin Cc: "Luis R. Rodriguez" , Jiri Slaby , "ath5k-devel@venema.h4ckr.net" , "linux-wireless@vger.kernel.org" , "linux-kernel@vger.kernel.org" , "John W. Linville" , mickflemm@gmail.com Subject: Re: [ath5k-devel] [PATCH 1/1] ath5k: fix hw rate index condition Message-ID: <20090303034600.GA3757@hash.localnet> (sfid-20090303_044707_531984_2BC085B5) References: <1235688271-22346-1-git-send-email-jirislaby@gmail.com> <20090226230338.M86894@bobcopeland.com> <49A7236E.2020807@gmail.com> <49A726A7.6090809@gmail.com> <20090227022704.GA29850@hash.localnet> <20090227023912.GF13456@tesla> <20090227030608.GA29974@hash.localnet> <1235884912.9224.26.camel@mj> MIME-Version: 1.0 Content-Type: text/plain; charset=us-ascii In-Reply-To: <1235884912.9224.26.camel@mj> Sender: linux-wireless-owner@vger.kernel.org List-ID: On Sun, Mar 01, 2009 at 12:21:52AM -0500, Pavel Roskin wrote: > I would prefer that we don't hide problems. > > If we don't know why we cannot get a valid rate, we should use WARN_ON > and find out why and when it happens. I'm fine with using a bogus rate > with WARN_ON. So here is at least stage one of this, not yet the global "unknown rate" infrastructure, but hopefully it will allow us to track down the issue. It makes hw_to_driver_rix a little uglier, but oh well. Thoughts? From: Bob Copeland Date: Mon, 2 Mar 2009 21:55:18 -0500 Subject: [PATCH] ath5k: warn and correct rate for unknown hw rate indexes ath5k sets up a mapping table from the hardware rate index to the rate index used by mac80211; however, we have seen some received frames with incorrect rate indexes. Such frames normally get dropped with a warning in __ieee80211_rx(), but the warning doesn't include enough context to track down the error. This patch adds a warning to hw_to_driver_rix for any lookups that result in a rate index of -1, then returns a valid rate so the frame can be processed. This also includes the bug fix suggested by Pavel Roskin, in which the mapping table is made signed, so rates initialized to -1 stay that way. Signed-off-by: Bob Copeland --- drivers/net/wireless/ath5k/base.c | 15 ++++++++++++--- drivers/net/wireless/ath5k/base.h | 2 +- 2 files changed, 13 insertions(+), 4 deletions(-) diff --git a/drivers/net/wireless/ath5k/base.c b/drivers/net/wireless/ath5k/base.c index f7c424d..8d4b11c 100644 --- a/drivers/net/wireless/ath5k/base.c +++ b/drivers/net/wireless/ath5k/base.c @@ -1100,9 +1100,18 @@ ath5k_mode_setup(struct ath5k_softc *sc) static inline int ath5k_hw_to_driver_rix(struct ath5k_softc *sc, int hw_rix) { - WARN(hw_rix < 0 || hw_rix >= AR5K_MAX_RATES, - "hw_rix out of bounds: %x\n", hw_rix); - return sc->rate_idx[sc->curband->band][hw_rix]; + int rix; + + /* return base rate on errors */ + if (WARN(hw_rix < 0 || hw_rix >= AR5K_MAX_RATES, + "hw_rix out of bounds: %x\n", hw_rix)) + return 0; + + rix = sc->rate_idx[sc->curband->band][hw_rix]; + if (WARN(rix < 0, "invalid hw_rix: %x\n", hw_rix)) + rix = 0; + + return rix; } /***************\ diff --git a/drivers/net/wireless/ath5k/base.h b/drivers/net/wireless/ath5k/base.h index 20e0d14..8229561 100644 --- a/drivers/net/wireless/ath5k/base.h +++ b/drivers/net/wireless/ath5k/base.h @@ -112,7 +112,7 @@ struct ath5k_softc { struct ieee80211_supported_band sbands[IEEE80211_NUM_BANDS]; struct ieee80211_channel channels[ATH_CHAN_MAX]; struct ieee80211_rate rates[IEEE80211_NUM_BANDS][AR5K_MAX_RATES]; - u8 rate_idx[IEEE80211_NUM_BANDS][AR5K_MAX_RATES]; + s8 rate_idx[IEEE80211_NUM_BANDS][AR5K_MAX_RATES]; enum nl80211_iftype opmode; struct ath5k_hw *ah; /* Atheros HW */ -- 1.6.0.6 -- Bob Copeland %% www.bobcopeland.com