From: David Miller <davem@davemloft.net>
To: jarkao2@gmail.com
Cc: eric.dumazet@gmail.com, netdev@vger.kernel.org
Subject: Re: [PATCH] pkt_sched: Fix lockdep warning on est_tree_lock in gen_estimator
Date: Thu, 02 Sep 2010 13:22:48 -0700 (PDT) [thread overview]
Message-ID: <20100902.132248.229742285.davem@davemloft.net> (raw)
In-Reply-To: <20100902201257.GA3089@del.dom.local>
From: Jarek Poplawski <jarkao2@gmail.com>
Date: Thu, 2 Sep 2010 22:12:58 +0200
> This patch fixes a lockdep warning:
>
> [ 516.287584] =========================================================
> [ 516.288386] [ INFO: possible irq lock inversion dependency detected ]
> [ 516.288386] 2.6.35b #7
> [ 516.288386] ---------------------------------------------------------
> [ 516.288386] swapper/0 just changed the state of lock:
> [ 516.288386] (&qdisc_tx_lock){+.-...}, at: [<c12eacda>] est_timer+0x62/0x1b4
> [ 516.288386] but this lock took another, SOFTIRQ-unsafe lock in the past:
> [ 516.288386] (est_tree_lock){+.+...}
> [ 516.288386]
> [ 516.288386] and interrupts could create inverse lock ordering between them.
> ...
>
> So, est_tree_lock needs BH protection because it's taken by
> qdisc_tx_lock, which is used both in BH and process contexts.
> (Full warning with this patch at netdev, 02 Sep 2010.)
>
> Fixes commit: ae638c47dc040b8def16d05dc6acdd527628f231
>
> Signed-off-by: Jarek Poplawski <jarkao2@gmail.com>
Applied, thanks Jarek.
Eric, please make an effort to run with lockdep enabled when making
locking changes, just for fun :-)
next prev parent reply other threads:[~2010-09-02 20:22 UTC|newest]
Thread overview: 8+ messages / expand[flat|nested] mbox.gz Atom feed top
2010-09-02 20:12 [PATCH] pkt_sched: Fix lockdep warning on est_tree_lock in gen_estimator Jarek Poplawski
2010-09-02 20:22 ` David Miller [this message]
2010-09-02 20:32 ` Eric Dumazet
2010-09-02 20:55 ` Jarek Poplawski
2010-09-03 5:26 ` Eric Dumazet
2010-09-02 20:53 ` Eric Dumazet
2010-09-02 20:59 ` David Miller
2010-09-02 21:22 ` Jarek Poplawski
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