From: Rusty Russell <rusty@rustcorp.com.au>
To: David Miller <davem@davemloft.net>
Cc: sfr@canb.auug.org.au, linux-next@vger.kernel.org,
alex.williamson@hp.com, linux-kernel@vger.kernel.org
Subject: Re: linux-next: upstream tree build warnings
Date: Sun, 26 Apr 2009 21:53:10 +0930 [thread overview]
Message-ID: <200904262153.10948.rusty@rustcorp.com.au> (raw)
In-Reply-To: <20090423.002403.74400050.davem@davemloft.net>
On Thu, 23 Apr 2009 04:54:03 pm David Miller wrote:
> From: Stephen Rothwell <sfr@canb.auug.org.au>
> Date: Thu, 23 Apr 2009 16:38:47 +1000
>
> > Today's linux-next build (powerpc allyesconfig gcc4.4.0) produced these
> > warnings:
> >
> > drivers/net/virtio_net.c: In function 'virnet_vlan_rx_add_vid':
> > include/linux/scatterlist.h:57: warning: 'sg' is used uninitialized in this function
> > drivers/net/virtio_net.c:746: note: 'sg' was declared here
> > drivers/net/virtio_net.c: In function 'virnet_vlan_rx_kill_vid':
> > include/linux/scatterlist.h:57: warning: 'sg' is used uninitialized in this function
> > drivers/net/virtio_net.c:758: note: 'sg' was declared here
> >
> > in each case, sg is uninitialised when its address is passed to
> > sg_set_buf() which passes it to gs_set_page() which passes it to
> > sg_assign_page() which dereferences it (to use ->page_link).
>
> I wonder if this is a side effect of changes that went in via Rusty's
> tree? I don't remember touching this driver in a while.
AFAICT gcc is right: it should be sg_init_one().
It doesn't currently *matter*, since no virtio add_buf implementation
does that chained-sg crap (I had a patch once, but it made me barf) and
so the uninitialized lower three bits are ignored.
Alex, if you agree, patch welcome...
Rusty.
next prev parent reply other threads:[~2009-04-26 12:23 UTC|newest]
Thread overview: 17+ messages / expand[flat|nested] mbox.gz Atom feed top
[not found] <20090423163847.200f227e.sfr@canb.auug.org.au>
2009-04-23 7:24 ` linux-next: upstream tree build warnings David Miller
2009-04-23 11:55 ` Stephen Rothwell
2009-04-23 12:51 ` Stephen Rothwell
2009-04-23 16:46 ` Alex Williamson
2009-04-26 12:23 ` Rusty Russell [this message]
2009-04-27 6:32 ` David Miller
2009-04-24 14:37 ` [PATCH] virtio_net: memset scatterlist before using Alex Williamson
2009-04-26 12:58 ` Rusty Russell
2009-04-27 6:30 ` David Miller
2009-04-27 15:50 ` [PATCH] virtio_net: Cleanup command queue scatterlist usage Alex Williamson
2009-04-28 9:30 ` David Miller
2009-05-01 22:33 ` David Miller
2009-05-01 22:43 ` Alex Williamson
2009-05-01 22:52 ` David Miller
2009-05-02 3:27 ` Alex Williamson
2009-05-02 4:26 ` David Miller
2009-05-05 3:21 ` Rusty Russell
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