netdev - Re: ipv6: handle -EFAULT from skb_copy

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Message-ID: <20161220181728.dd2cynjwrceruwcu@codemonkey.org.uk>
Date:   Tue, 20 Dec 2016 13:17:28 -0500
From:   Dave Jones <davej@...emonkey.org.uk>
To:     David Miller <davem@...emloft.net>
Cc:     netdev@...r.kernel.org
Subject: Re: ipv6: handle -EFAULT from skb_copy_bits

On Mon, Dec 19, 2016 at 08:36:23PM -0500, David Miller wrote:
 > From: Dave Jones <davej@...emonkey.org.uk>
 > Date: Mon, 19 Dec 2016 19:40:13 -0500
 > 
 > > On Mon, Dec 19, 2016 at 07:31:44PM -0500, Dave Jones wrote:
 > > 
 > >  > Unfortunately, this made no difference.  I spent some time today trying
 > >  > to make a better reproducer, but failed. I'll revisit again tomorrow.
 > >  > 
 > >  > Maybe I need >1 process/thread to trigger this.  That would explain why
 > >  > I can trigger it with Trinity.
 > > 
 > > scratch that last part, I finally just repro'd it with a single process.
 > 
 > Thanks for the info, I'll try to think about this some more.

I threw in some debug printks right before that BUG_ON.
it's always this:

skb->len=31 skb->data_len=0 offset:30 total_len:9

Shouldn't we have kicked out data_len=0 skb's somewhere before we got this far ?

	Dave