Re: [PATCH v2 3/9] vfio: New external user group/file match

From: kbuild test robot <lkp@intel.com>
To: Alex Williamson <alex.williamson@redhat.com>
Cc: kbuild-all@01.org, kvm@vger.kernel.org, eric.auger@redhat.com,
	alex.williamson@redhat.com, linux-kernel@vger.kernel.org,
	stable@vger.kernel.org, Paolo Bonzini <pbonzini@redhat.com>
Subject: Re: [PATCH v2 3/9] vfio: New external user group/file match
Date: Tue, 20 Jun 2017 13:01:41 +0800	[thread overview]
Message-ID: <201706201245.gdsrXosM%fengguang.wu@intel.com> (raw)
In-Reply-To: <20170619171446.14047.609.stgit@gimli.home>

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Hi Alex,

[auto build test ERROR on vfio/next]
[also build test ERROR on v4.12-rc6 next-20170619]
[if your patch is applied to the wrong git tree, please drop us a note to help improve the system]

url:    https://github.com/0day-ci/linux/commits/Alex-Williamson/vfio-Fix-release-ordering-races-and-use-driver_override/20170620-095741
base:   https://github.com/awilliam/linux-vfio.git next
config: powerpc-defconfig (attached as .config)
compiler: powerpc64-linux-gnu-gcc (Debian 6.1.1-9) 6.1.1 20160705
reproduce:
        wget https://raw.githubusercontent.com/01org/lkp-tests/master/sbin/make.cross -O ~/bin/make.cross
        chmod +x ~/bin/make.cross
        # save the attached .config to linux build tree
        make.cross ARCH=powerpc 

Note: it may well be a FALSE warning. FWIW you are at least aware of it now.
http://gcc.gnu.org/wiki/Better_Uninitialized_Warnings

All errors (new ones prefixed by >>):

   arch/powerpc/kvm/../../../virt/kvm/vfio.c: In function 'kvm_vfio_set_attr':
>> arch/powerpc/kvm/../../../virt/kvm/vfio.c:262:4: error: 'vfio_group' may be used uninitialized in this function [-Werror=maybe-uninitialized]
       kvm_spapr_tce_release_vfio_group(dev->kvm, vfio_group);
       ^~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~
   arch/powerpc/kvm/../../../virt/kvm/vfio.c:190:21: note: 'vfio_group' was declared here
     struct vfio_group *vfio_group;
                        ^~~~~~~~~~
   cc1: all warnings being treated as errors

vim +/vfio_group +262 arch/powerpc/kvm/../../../virt/kvm/vfio.c

600c6bde Alex Williamson 2017-06-19  256  								f.file))
ec53500f Alex Williamson 2013-10-30  257  				continue;
ec53500f Alex Williamson 2013-10-30  258  
ec53500f Alex Williamson 2013-10-30  259  			list_del(&kvg->node);
14979b3f Alex Williamson 2017-06-19  260  			kvm_arch_end_assignment(dev->kvm);
14979b3f Alex Williamson 2017-06-19  261  #ifdef CONFIG_SPAPR_TCE_IOMMU
14979b3f Alex Williamson 2017-06-19 @262  			kvm_spapr_tce_release_vfio_group(dev->kvm, vfio_group);
14979b3f Alex Williamson 2017-06-19  263  #endif
14979b3f Alex Williamson 2017-06-19  264  			kvm_vfio_group_set_kvm(kvg->vfio_group, NULL);
ec53500f Alex Williamson 2013-10-30  265  			kvm_vfio_group_put_external_user(kvg->vfio_group);

:::::: The code at line 262 was first introduced by commit
:::::: 14979b3f26fbbe87d4240e463db53e64dd127184 kvm-vfio: Decouple only when we match a group

:::::: TO: Alex Williamson <alex.williamson@redhat.com>
:::::: CC: 0day robot <fengguang.wu@intel.com>

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0-DAY kernel test infrastructure                Open Source Technology Center
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