From: Johannes Berg <johannes@sipsolutions.net>
To: Calvin Owens <jcalvinowens@gmail.com>
Cc: linux-wireless@vger.kernel.org, linux-kernel@vger.kernel.org
Subject: Re: [PATCH] mac80211: Fix bogus RCU warning from ieee80211_get_tx_rates (Was: Re: rcu)
Date: Tue, 11 Jun 2013 13:42:06 +0200 [thread overview]
Message-ID: <1370950926.8356.14.camel@jlt4.sipsolutions.net> (raw)
In-Reply-To: <20130610042959.GA1902@gmail.com> (sfid-20130610_063023_078105_2ADDB0AE)
On Sun, 2013-06-09 at 23:29 -0500, Calvin Owens wrote:
> rate_control_fill_sta_table(), whose sole caller is ieee80211_get_tx_rates(),
> is guaranteed by mac80211 not to be called concurrently with
> rate_control_set_rates() [1], the sole function that touches the rate table
> pointer/data in struct ieee80211_sta. The RCU dereference is therefore safe.
No, this is wrong. ieee80211_get_tx_rates() can be called by drivers in
any context and at any time, that was the whole point of using RCU here.
This needs to be fixed in ath9k, calling ieee80211_get_tx_rates() must
be done under RCU protection.
johannes
next prev parent reply other threads:[~2013-06-11 11:42 UTC|newest]
Thread overview: 10+ messages / expand[flat|nested] mbox.gz Atom feed top
2013-06-09 22:51 rcu Calvin Owens
2013-06-10 4:29 ` [PATCH] mac80211: Fix bogus RCU warning from ieee80211_get_tx_rates (Was: Re: rcu) Calvin Owens
2013-06-11 11:42 ` Johannes Berg [this message]
2013-06-11 17:13 ` [PATCH] mac80211: ath9k: Use RCU protection calling ieee80211_get_tx_rates Calvin Owens
2013-06-11 19:55 ` Johannes Berg
2013-06-12 6:37 ` Kalle Valo
2013-06-12 7:56 ` Calvin Owens
2013-06-12 8:00 ` [PATCH] mac80211: Use RCU protection in ieee80211_get_tx_rates() Calvin Owens
2013-06-12 9:47 ` Felix Fietkau
2013-06-13 15:27 ` Calvin Owens
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