Subject: Re: [2.6 patch] net/sctp/socket.c: add missing
	sctp_spin_unlock_irqrestore
From: Arjan van de Ven <arjan@infradead.org>
To: Al Viro <viro@ftp.linux.org.uk>
Cc: Eugene Teo <eteo@redhat.com>, lksctp-developers@lists.sourceforge.net,
       linux-kernel@vger.kernel.org
In-Reply-To: <20061126101254.GW3078@ftp.linux.org.uk>
References: <456965D5.1000302@redhat.com>
	 <20061126101254.GW3078@ftp.linux.org.uk>
Content-Type: text/plain
Organization: Intel International BV
Date: Sun, 26 Nov 2006 11:19:12 +0100
Message-Id: <1164536353.3147.70.camel@laptopd505.fenrus.org>
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On Sun, 2006-11-26 at 10:12 +0000, Al Viro wrote:
> On Sun, Nov 26, 2006 at 06:00:53PM +0800, Eugene Teo wrote:
> > This patch adds a missing sctp_spin_unlock_irqrestore when returning
> > from "if(space_left<addrlen)" condition.
> >                 if (copy_to_user(*to, &temp, addrlen)) {
> > -                       sctp_spin_unlock_irqrestore(&sctp_local_addr_lock,
> > -                                                   flags);
> > -                       return -EFAULT;
> > +                       err = -EFAULT;
> > +                       goto unlock;
> 
> > +       sctp_spin_unlock_irqrestore(&sctp_local_addr_lock, flags);
> > +       return err;
> >  }
> 
> You do realize that it's obviously still badly broken, don't you?
> copy_to_user() under a spinlock is a recipe for deadlock, especially
> if you've got interrupts disabled...
> 
> I have a beginning of locking fixes in that shitpile, but it's incomplete
> and bloody painful ;-/
> -

do your patches also remove the empty abstraction of the sctp_ prefix
around the spinlock use in sctp ?


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