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From: Eric Dumazet <eric.dumazet@gmail.com>
To: Frederic Weisbecker <fweisbec@gmail.com>
Cc: "David S. Miller" <davem@davemloft.net>,
	Neil Horman <nhorman@tuxdriver.com>,
	Netdev <netdev@vger.kernel.org>,
	LKML <linux-kernel@vger.kernel.org>
Subject: Re: packet_sendmsg_spkt sleeping from invalid context
Date: Mon, 14 Dec 2009 22:25:57 +0100	[thread overview]
Message-ID: <4B26AD65.1020004@gmail.com> (raw)
In-Reply-To: <20091214205231.GB5037@nowhere>

Le 14/12/2009 21:52, Frederic Weisbecker a écrit :
> 
> I also wonder. Are you using PREEMPT_RCU ?

Not at all :)

But yes, this is illegal to do the memcpy_fromiovec() in rcu_read_lock() context.

> That may explain why you haven't seen this issue because
> might_sleep() doesn't see you are in a rcu read locked
> section as preemption is not disabled, but it is illegal to
> voluntarily sleep in such area (although it's fine with
> preempt rcu) as doing so with non-prempt RCU config would barf.
> 
> I'm trying a patch to handle that.

As you want, I also have a patch testing right now :)

  reply	other threads:[~2009-12-14 21:25 UTC|newest]

Thread overview: 10+ messages / expand[flat|nested]  mbox.gz  Atom feed  top
2009-12-14 17:52 packet_sendmsg_spkt sleeping from invalid context Frederic Weisbecker
2009-12-14 19:24 ` Eric Dumazet
2009-12-14 20:11   ` Frederic Weisbecker
2009-12-14 20:52   ` Frederic Weisbecker
2009-12-14 21:25     ` Eric Dumazet [this message]
2009-12-14 21:30       ` Frederic Weisbecker
2009-12-14 21:39         ` Eric Dumazet
2009-12-15 15:13           ` Frederic Weisbecker
2009-12-15 15:47             ` Eric Dumazet
2009-12-16  5:14               ` David Miller

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