From: "Paul E. McKenney" <paulmck@linux.vnet.ibm.com>
To: Larry Finger <Larry.Finger@lwfinger.net>
Cc: Catalin Marinas <catalin.marinas@arm.com>,
Johannes Berg <johannes@sipsolutions.net>,
Mohammed Shafi <shafi.wireless@gmail.com>,
wireless <linux-wireless@vger.kernel.org>
Subject: Re: Suspicious RCU usage in mac80211
Date: Thu, 3 May 2012 10:12:09 -0700 [thread overview]
Message-ID: <20120503171209.GH2592@linux.vnet.ibm.com> (raw)
In-Reply-To: <4FA2B845.2000502@lwfinger.net>
On Thu, May 03, 2012 at 11:54:29AM -0500, Larry Finger wrote:
> On 05/03/2012 03:47 AM, Catalin Marinas wrote:
> >
> >IIUC, Paul suggested that you should use rcu_dereference_check() here
> >instead as the protected one is not safe in this context.
>
> This patch also fails to fix the problem. Did I do what Paul suggested?
That is indeed what I suggested!
What locks does lockdep say are held?
Thanx, Paul
> Index: wireless-testing-new/net/mac80211/sta_info.h
> ===================================================================
> --- wireless-testing-new.orig/net/mac80211/sta_info.h
> +++ wireless-testing-new/net/mac80211/sta_info.h
> @@ -452,7 +452,7 @@ void ieee80211_assign_tid_tx(struct sta_
> static inline struct tid_ampdu_tx *
> rcu_dereference_protected_tid_tx(struct sta_info *sta, int tid)
> {
> - return rcu_dereference_protected(sta->ampdu_mlme.tid_tx[tid],
> + return rcu_dereference_check(sta->ampdu_mlme.tid_tx[tid],
> lockdep_is_held(&sta->lock) ||
> lockdep_is_held(&sta->ampdu_mlme.mtx));
> }
>
next prev parent reply other threads:[~2012-05-03 17:12 UTC|newest]
Thread overview: 25+ messages / expand[flat|nested] mbox.gz Atom feed top
2012-04-10 3:19 Suspicious RCU usage in mac80211 Larry Finger
2012-04-12 3:31 ` Johannes Berg
2012-04-12 3:51 ` Larry Finger
2012-04-12 3:54 ` Johannes Berg
2012-04-12 15:51 ` Larry Finger
2012-04-12 15:55 ` Johannes Berg
2012-05-01 14:25 ` Mohammed Shafi
2012-05-01 19:18 ` Larry Finger
2012-05-02 5:02 ` Mohammed Shafi
2012-05-02 10:00 ` Catalin Marinas
2012-05-02 17:07 ` Johannes Berg
2012-05-02 20:09 ` Paul E. McKenney
2012-05-03 18:38 ` Johannes Berg
2012-05-04 6:17 ` Larry Finger
2012-05-04 6:40 ` Mohammed Shafi
2012-05-04 6:48 ` Mohammed Shafi
2012-05-04 13:45 ` Larry Finger
2012-05-04 14:35 ` Mohammed Shafi
2012-05-03 3:02 ` Larry Finger
2012-05-03 8:47 ` Catalin Marinas
2012-05-03 16:54 ` Larry Finger
2012-05-03 17:12 ` Paul E. McKenney [this message]
2012-05-03 17:46 ` Larry Finger
2012-05-03 18:22 ` Paul E. McKenney
2012-05-03 18:32 ` Larry Finger
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