Re: [PATCH bpf-next 5/8] bpf: Add link-based BPF program attachment to network namespace

On Wed, May 27, 2020 at 8:19 PM kbuild test robot [off-list ref] wrote:

Hi Jakub,

I love your patch! Perhaps something to improve:

[auto build test WARNING on bpf-next/master]
[also build test WARNING on net-next/master next-20200526]
[cannot apply to bpf/master net/master linus/master v5.7-rc7]
[if your patch is applied to the wrong git tree, please drop us a note to help
improve the system. BTW, we also suggest to use '--base' option to specify the
base tree in git format-patch, please see https://stackoverflow.com/a/37406982]

url:    https://github.com/0day-ci/linux/commits/Jakub-Sitnicki/Link-based-program-attachment-to-network-namespaces/20200528-011159
base:   https://git.kernel.org/pub/scm/linux/kernel/git/bpf/bpf-next.git master
config: arm-randconfig-r035-20200527 (attached as .config)
compiler: clang version 11.0.0 (https://github.com/llvm/llvm-project 3393cc4cebf9969db94dc424b7a2b6195589c33b)
reproduce (this is a W=1 build):
        wget https://raw.githubusercontent.com/intel/lkp-tests/master/sbin/make.cross -O ~/bin/make.cross
        chmod +x ~/bin/make.cross
        # install arm cross compiling tool for clang build
        # apt-get install binutils-arm-linux-gnueabi
        # save the attached .config to linux build tree
        COMPILER_INSTALL_PATH=$HOME/0day COMPILER=clang make.cross ARCH=arm

If you fix the issue, kindly add following tag as appropriate
Reported-by: kbuild test robot <redacted>

All warnings (new ones prefixed by >>, old ones prefixed by <<):

quoted

quoted

kernel/bpf/net_namespace.c:130:6: warning: variable 'inum' is used uninitialized whenever 'if' condition is false [-Wsometimes-uninitialized]

This looks legit to me. Please fix.

if (net)
^~~
kernel/bpf/net_namespace.c:134:26: note: uninitialized use occurs here
info->netns.netns_ino = inum;
^~~~
kernel/bpf/net_namespace.c:130:2: note: remove the 'if' if its condition is always true
if (net)
^~~~~~~~
kernel/bpf/net_namespace.c:123:19: note: initialize the variable 'inum' to silence this warning
unsigned int inum;
^
= 0
1 warning generated.

vim +130 kernel/bpf/net_namespace.c

   118
   119  static int bpf_netns_link_fill_info(const struct bpf_link *link,
   120                                      struct bpf_link_info *info)
   121  {
   122          const struct bpf_netns_link *net_link;
   123          unsigned int inum;
   124          struct net *net;
   125
   126          net_link = container_of(link, struct bpf_netns_link, link);
   127
   128          rcu_read_lock();
   129          net = rcu_dereference(net_link->net);
 > 130          if (net)
   131                  inum = net->ns.inum;
   132          rcu_read_unlock();
   133
   134          info->netns.netns_ino = inum;
   135          info->netns.attach_type = net_link->type;
   136          return 0;
   137  }
   138

---
0-DAY CI Kernel Test Service, Intel Corporation
https://lists.01.org/hyperkitty/list/kbuild-all@lists.01.org

--
You received this message because you are subscribed to the Google Groups "Clang Built Linux" group.
To unsubscribe from this group and stop receiving emails from it, send an email to clang-built-linux+unsubscribe@googlegroups.com.
To view this discussion on the web visit https://groups.google.com/d/msgid/clang-built-linux/202005281031.S7IMfvFG%25lkp%40intel.com.

-- 
Thanks,
~Nick Desaulniers