Re: linux-next: Tree for May 16 (net/core)

From: Paul Gortmaker
Date: Tue May 16 2017 - 15:45:18 EST

On Tue, May 16, 2017 at 12:28 PM, Randy Dunlap <rdunlap@xxxxxxxxxxxxx> wrote:
> On 05/15/17 18:21, Stephen Rothwell wrote:
>> Hi all,
>> Changes since 20170515:
> on i386 or x86_64:
> when CONFIG_INET is not enabled:
> ../net/core/sock.c: In function 'skb_orphan_partial':
> ../net/core/sock.c:1810:2: error: implicit declaration of function 'skb_is_tcp_pure_ack' [-Werror=implicit-function-declaration]
> if (skb_is_tcp_pure_ack(skb))

Automated bisect on an ARM build with the same issue reveals:

f6ba8d33cfbb46df569972e64dbb5bb7e929bfd9 is the first bad commit
commit f6ba8d33cfbb46df569972e64dbb5bb7e929bfd9
Author: Eric Dumazet <edumazet@xxxxxxxxxx>
Date: Thu May 11 15:24:41 2017 -0700

netem: fix skb_orphan_partial()

I should have known that lowering skb->truesize was dangerous :/

In case packets are not leaving the host via a standard Ethernet device,
but looped back to local sockets, bad things can happen, as reported
by Michael Madsen ( )

So instead of tweaking skb->truesize, lets change skb->destructor
and keep a reference on the owner socket via its sk_refcnt.

Fixes: f2f872f9272a ("netem: Introduce skb_orphan_partial() helper")
Signed-off-by: Eric Dumazet <edumazet@xxxxxxxxxx>
Reported-by: Michael Madsen <mkm@xxxxxxxxx>
Signed-off-by: David S. Miller <davem@xxxxxxxxxxxxx>

:040000 040000 7bfb7a6f5e12373b1c50ede2455b6ddd6d79cee0
b45b7255322f1dff5e3ab8d3d707cf38a91c76ce M net
bisect run success

I'm guessing Eric already knows about this but I've Cc'd him just in case.


> --
> ~Randy