linux-kernel - Re: packet_sendmsg_spkt sleeping from invalid context

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Message-ID: <4B26AD65.1020004@gmail.com>
Date:	Mon, 14 Dec 2009 22:25:57 +0100
From:	Eric Dumazet <eric.dumazet@...il.com>
To:	Frederic Weisbecker <fweisbec@...il.com>
CC:	"David S. Miller" <davem@...emloft.net>,
	Neil Horman <nhorman@...driver.com>,
	Netdev <netdev@...r.kernel.org>,
	LKML <linux-kernel@...r.kernel.org>
Subject: Re: packet_sendmsg_spkt sleeping from invalid context

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 :)
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