Re: [PATCH net-next] netlink: make getters tolerate NULL nla arg

[kbuild test robot <lkp@intel.com>]

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Hi Florian,

I love your patch! Perhaps something to improve:

[auto build test WARNING on net-next/master]
[also build test WARNING on net/master linus/master ipvs/master v5.5-rc6 next-20200117]
[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/Florian-Westphal/netlink-make-getters-tolerate-NULL-nla-arg/20200117-200009
base:   https://git.kernel.org/pub/scm/linux/kernel/git/davem/net-next.git 6bc8038035267d12df2bf78a8e1a5f07069fabb8
config: i386-randconfig-c001-20200117 (attached as .config)
compiler: gcc-7 (Debian 7.5.0-3) 7.5.0
reproduce:
        # save the attached .config to linux build tree
        make ARCH=i386 

If you fix the issue, kindly add following tag
Reported-by: kbuild test robot <lkp@intel.com>

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 warnings (new ones prefixed by >>):

   net/ieee802154/nl802154.c: In function '__cfg802154_wpan_dev_from_attrs.constprop':
>> net/ieee802154/nl802154.c:75:32: warning: 'wpan_dev_id' may be used uninitialized in this function [-Wmaybe-uninitialized]
           wpan_dev->identifier == (u32)wpan_dev_id) {
                                   ^~~~~~~~~~~~~~~~

vim +/wpan_dev_id +75 net/ieee802154/nl802154.c

79fe1a2aa7b504 Alexander Aring 2014-11-09  34  
79fe1a2aa7b504 Alexander Aring 2014-11-09  35  /* returns ERR_PTR values */
79fe1a2aa7b504 Alexander Aring 2014-11-09  36  static struct wpan_dev *
79fe1a2aa7b504 Alexander Aring 2014-11-09  37  __cfg802154_wpan_dev_from_attrs(struct net *netns, struct nlattr **attrs)
79fe1a2aa7b504 Alexander Aring 2014-11-09  38  {
79fe1a2aa7b504 Alexander Aring 2014-11-09  39  	struct cfg802154_registered_device *rdev;
79fe1a2aa7b504 Alexander Aring 2014-11-09  40  	struct wpan_dev *result = NULL;
79fe1a2aa7b504 Alexander Aring 2014-11-09  41  	bool have_ifidx = attrs[NL802154_ATTR_IFINDEX];
79fe1a2aa7b504 Alexander Aring 2014-11-09  42  	bool have_wpan_dev_id = attrs[NL802154_ATTR_WPAN_DEV];
79fe1a2aa7b504 Alexander Aring 2014-11-09  43  	u64 wpan_dev_id;
79fe1a2aa7b504 Alexander Aring 2014-11-09  44  	int wpan_phy_idx = -1;
79fe1a2aa7b504 Alexander Aring 2014-11-09  45  	int ifidx = -1;
79fe1a2aa7b504 Alexander Aring 2014-11-09  46  
79fe1a2aa7b504 Alexander Aring 2014-11-09  47  	ASSERT_RTNL();
79fe1a2aa7b504 Alexander Aring 2014-11-09  48  
79fe1a2aa7b504 Alexander Aring 2014-11-09  49  	if (!have_ifidx && !have_wpan_dev_id)
79fe1a2aa7b504 Alexander Aring 2014-11-09  50  		return ERR_PTR(-EINVAL);
79fe1a2aa7b504 Alexander Aring 2014-11-09  51  
79fe1a2aa7b504 Alexander Aring 2014-11-09  52  	if (have_ifidx)
79fe1a2aa7b504 Alexander Aring 2014-11-09  53  		ifidx = nla_get_u32(attrs[NL802154_ATTR_IFINDEX]);
79fe1a2aa7b504 Alexander Aring 2014-11-09  54  	if (have_wpan_dev_id) {
79fe1a2aa7b504 Alexander Aring 2014-11-09  55  		wpan_dev_id = nla_get_u64(attrs[NL802154_ATTR_WPAN_DEV]);
79fe1a2aa7b504 Alexander Aring 2014-11-09  56  		wpan_phy_idx = wpan_dev_id >> 32;
79fe1a2aa7b504 Alexander Aring 2014-11-09  57  	}
79fe1a2aa7b504 Alexander Aring 2014-11-09  58  
79fe1a2aa7b504 Alexander Aring 2014-11-09  59  	list_for_each_entry(rdev, &cfg802154_rdev_list, list) {
79fe1a2aa7b504 Alexander Aring 2014-11-09  60  		struct wpan_dev *wpan_dev;
79fe1a2aa7b504 Alexander Aring 2014-11-09  61  
66e5c2672cd11b Alexander Aring 2016-06-18  62  		if (wpan_phy_net(&rdev->wpan_phy) != netns)
66e5c2672cd11b Alexander Aring 2016-06-18  63  			continue;
79fe1a2aa7b504 Alexander Aring 2014-11-09  64  
79fe1a2aa7b504 Alexander Aring 2014-11-09  65  		if (have_wpan_dev_id && rdev->wpan_phy_idx != wpan_phy_idx)
79fe1a2aa7b504 Alexander Aring 2014-11-09  66  			continue;
79fe1a2aa7b504 Alexander Aring 2014-11-09  67  
79fe1a2aa7b504 Alexander Aring 2014-11-09  68  		list_for_each_entry(wpan_dev, &rdev->wpan_dev_list, list) {
79fe1a2aa7b504 Alexander Aring 2014-11-09  69  			if (have_ifidx && wpan_dev->netdev &&
79fe1a2aa7b504 Alexander Aring 2014-11-09  70  			    wpan_dev->netdev->ifindex == ifidx) {
79fe1a2aa7b504 Alexander Aring 2014-11-09  71  				result = wpan_dev;
79fe1a2aa7b504 Alexander Aring 2014-11-09  72  				break;
79fe1a2aa7b504 Alexander Aring 2014-11-09  73  			}
79fe1a2aa7b504 Alexander Aring 2014-11-09  74  			if (have_wpan_dev_id &&
79fe1a2aa7b504 Alexander Aring 2014-11-09 @75  			    wpan_dev->identifier == (u32)wpan_dev_id) {
79fe1a2aa7b504 Alexander Aring 2014-11-09  76  				result = wpan_dev;
79fe1a2aa7b504 Alexander Aring 2014-11-09  77  				break;
79fe1a2aa7b504 Alexander Aring 2014-11-09  78  			}
79fe1a2aa7b504 Alexander Aring 2014-11-09  79  		}
79fe1a2aa7b504 Alexander Aring 2014-11-09  80  
79fe1a2aa7b504 Alexander Aring 2014-11-09  81  		if (result)
79fe1a2aa7b504 Alexander Aring 2014-11-09  82  			break;
79fe1a2aa7b504 Alexander Aring 2014-11-09  83  	}
79fe1a2aa7b504 Alexander Aring 2014-11-09  84  
79fe1a2aa7b504 Alexander Aring 2014-11-09  85  	if (result)
79fe1a2aa7b504 Alexander Aring 2014-11-09  86  		return result;
79fe1a2aa7b504 Alexander Aring 2014-11-09  87  
79fe1a2aa7b504 Alexander Aring 2014-11-09  88  	return ERR_PTR(-ENODEV);
79fe1a2aa7b504 Alexander Aring 2014-11-09  89  }
79fe1a2aa7b504 Alexander Aring 2014-11-09  90  

:::::: The code at line 75 was first introduced by commit
:::::: 79fe1a2aa7b504c68642e510154f17e2de60da60 ieee802154: add nl802154 framework

:::::: TO: Alexander Aring <alex.aring@gmail.com>
:::::: CC: Marcel Holtmann <marcel@holtmann.org>

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

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