Re: [kbuild-all] [PATCH v17 net-next 1/1] hv_sock: introduce Hyper-V Sockets

[Fengguang Wu]

On Tue, Jul 19, 2016 at 07:52:53PM -0700, David Miller wrote:
> From: Dexuan Cui <decui@xxxxxxxxxxxxx>
> Date: Wed, 20 Jul 2016 01:48:18 +0000
>
> > > From: kbuild test robot [mailto:lkp@xxxxxxxxx]
> > > Sent: Wednesday, July 20, 2016 1:10
> > >
> > > Hi,
> > >
> > > [auto build test WARNING on net-next/master]
> > >
> > > url:    https://github.com/0day-ci/linux/commits/Dexuan-Cui/introduce-
> > > Hyper-V-VM-Sockets-hv_sock/20160715-223433
> > > config: x86_64-randconfig-a0-07191719 (attached as .config)
> > > compiler: gcc-4.4 (Debian 4.4.7-8) 4.4.7
> > > reproduce:
> > >         # save the attached .config to linux build tree
> > >         make ARCH=x86_64
> > >
> > > All warnings (new ones prefixed by >>):
> > >
> > >    net/hv_sock/af_hvsock.c: In function 'hvsock_open_connection':
> > >    net/hv_sock/af_hvsock.c:693: warning: 'hvsk' may be used uninitialized in
> > > this function
> > >    net/hv_sock/af_hvsock.c:693: warning: 'new_hvsk' may be used
> > > uninitialized in this function
> > >    net/hv_sock/af_hvsock.c:697: warning: 'new_sk' may be used uninitialized
> > > in this function
> > >    net/hv_sock/af_hvsock.c: In function 'hvsock_sendmsg_wait':
> > >    net/hv_sock/af_hvsock.c:1053: warning: 'ret' may be used uninitialized in
> > > this function
> > > >> net/hv_sock/af_hvsock.o: warning: objtool: hvsock_on_channel_cb()+0x1d:
> > > function has unreachable instruction
> >
> > These warnings are all false alarms.
>
> But you still have to quiet them.

Agreed.

However the last warning

       objtool: hvsock_on_channel_cb()+0x1d: function has unreachable instruction

is my fault -- it turns out to be a problem with old gcc-4.4 and
gcc-4.6 which we enabled 2 days ago. I just disabled reporting this
odd warning because it complaints on ~10000 functions all over the
place, which can only be sanely fixed in the toolchain.

Thanks,
Fengguang