drivers/virtio/virtio_balloon.o: warning: objtool: release_pages_balloon()+0x98: function has unreachable instruction

drivers/virtio/virtio_balloon.o: warning: objtool: release_pages_balloon()+0x98: function has unreachable instruction

[kbuild test robot]

[-- Attachment #1: Type: text/plain, Size: 1452 bytes --]

tree:   https://git.kernel.org/pub/scm/linux/kernel/git/torvalds/linux.git master
head:   47ef4ad2684d380dd6d596140fb79395115c3950
commit: 87c9403b0d1de4676b0bd273eea68fcf6de68e68 virtio_balloon: fix PFN format for virtio-1
date:   8 weeks ago
config: x86_64-randconfig-a0-07191719 (attached as .config)
compiler: gcc-4.4 (Debian 4.4.7-8) 4.4.7
reproduce:
        git checkout 87c9403b0d1de4676b0bd273eea68fcf6de68e68
        # save the attached .config to linux build tree
        make ARCH=x86_64 

All warnings (new ones prefixed by >>):

   drivers/virtio/virtio_balloon.c: In function 'update_balloon_stats':
   drivers/virtio/virtio_balloon.c:249: warning: 'events[2]' is used uninitialized in this function
   drivers/virtio/virtio_balloon.c:251: warning: 'events[3]' is used uninitialized in this function
   drivers/virtio/virtio_balloon.c:232: warning: 'events[12]' is used uninitialized in this function
   drivers/virtio/virtio_balloon.c:239: note: 'events[12]' was declared here
   drivers/virtio/virtio_balloon.c:232: warning: 'events[11]' is used uninitialized in this function
   drivers/virtio/virtio_balloon.c:239: note: 'events[11]' was declared here
>> drivers/virtio/virtio_balloon.o: warning: objtool: release_pages_balloon()+0x98: function has unreachable instruction

---
0-DAY kernel test infrastructure                Open Source Technology Center
https://lists.01.org/pipermail/kbuild-all                   Intel Corporation

[-- Attachment #2: .config.gz --]
[-- Type: application/octet-stream, Size: 27753 bytes --]

Re: [kbuild-all] drivers/virtio/virtio_balloon.o: warning: objtool: release_pages_balloon()+0x98: function has unreachable instruction

[Fengguang Wu]

Hi Cornelia, Michael,

Sorry please ignore this one -- it looks like false warning from old
gcc 4.4 and 4.6 -- we just enabled old compiler tests triggered
thousands of these warnings..

Thanks,
Fengguang

On Wed, Jul 20, 2016 at 01:33:15AM +0800, kbuild test robot wrote:
>tree:   https://git.kernel.org/pub/scm/linux/kernel/git/torvalds/linux.git master
>head:   47ef4ad2684d380dd6d596140fb79395115c3950
>commit: 87c9403b0d1de4676b0bd273eea68fcf6de68e68 virtio_balloon: fix PFN format for virtio-1
>date:   8 weeks ago
>config: x86_64-randconfig-a0-07191719 (attached as .config)
>compiler: gcc-4.4 (Debian 4.4.7-8) 4.4.7
>reproduce:
>        git checkout 87c9403b0d1de4676b0bd273eea68fcf6de68e68
>        # save the attached .config to linux build tree
>        make ARCH=x86_64
>
>All warnings (new ones prefixed by >>):
>
>   drivers/virtio/virtio_balloon.c: In function 'update_balloon_stats':
>   drivers/virtio/virtio_balloon.c:249: warning: 'events[2]' is used uninitialized in this function
>   drivers/virtio/virtio_balloon.c:251: warning: 'events[3]' is used uninitialized in this function
>   drivers/virtio/virtio_balloon.c:232: warning: 'events[12]' is used uninitialized in this function
>   drivers/virtio/virtio_balloon.c:239: note: 'events[12]' was declared here
>   drivers/virtio/virtio_balloon.c:232: warning: 'events[11]' is used uninitialized in this function
>   drivers/virtio/virtio_balloon.c:239: note: 'events[11]' was declared here
>>> drivers/virtio/virtio_balloon.o: warning: objtool: release_pages_balloon()+0x98: function has unreachable instruction
>
>---
>0-DAY kernel test infrastructure                Open Source Technology Center
>https://lists.01.org/pipermail/kbuild-all                   Intel Corporation


>_______________________________________________
>kbuild-all mailing list
>kbuild-all@lists.01.org
>https://lists.01.org/mailman/listinfo/kbuild-all