linux-kernel - Re: [PATCH] bpf: Call rcu_read_unlock() before copy_to

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Message-ID: <CAADnVQJa5KNkLWeSwC6X_4WJ5bPS9Me+EZqqJSO77RCg4fHwWQ@mail.gmail.com>
Date:	Thu, 22 Jan 2015 10:03:09 -0800
From:	Alexei Starovoitov <alexei.starovoitov@...il.com>
To:	Michael Holzheu <holzheu@...ux.vnet.ibm.com>
Cc:	Alexei Starovoitov <ast@...nel.org>,
	Martin Schwidefsky <schwidefsky@...ibm.com>,
	"linux-kernel@...r.kernel.org" <linux-kernel@...r.kernel.org>,
	"netdev@...r.kernel.org" <netdev@...r.kernel.org>
Subject: Re: [PATCH] bpf: Call rcu_read_unlock() before copy_to_user()

On Thu, Jan 22, 2015 at 9:54 AM, Michael Holzheu
<holzheu@...ux.vnet.ibm.com> wrote:
>> > So call rcu_read_unlock() before copy_to_user(). We can
>> > release the lock earlier because it is not needed for copy_to_user().
>>
>> we cannot move the rcu unlock this way, since it protects the value.
>> So we need to copy the value while still under rcu.
>
> Ok, right. I assume you will provide the correct fix.

sure :) will do.
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