Re: [PATCH v1 net-next 10/13] ipv6: Factorise ip6_route_multipath_add().

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

BCC: lkp@intel.com
CC: oe-kbuild-all@lists.linux.dev
In-Reply-To: <20250321040131.21057-11-kuniyu@amazon.com>
References: <20250321040131.21057-11-kuniyu@amazon.com>
TO: Kuniyuki Iwashima <kuniyu@amazon.com>
TO: "David S. Miller" <davem@davemloft.net>
CC: netdev@vger.kernel.org
TO: David Ahern <dsahern@kernel.org>
TO: Eric Dumazet <edumazet@google.com>
TO: Jakub Kicinski <kuba@kernel.org>
TO: Paolo Abeni <pabeni@redhat.com>
CC: Simon Horman <horms@kernel.org>
CC: Kuniyuki Iwashima <kuniyu@amazon.com>

Hi Kuniyuki,

kernel test robot noticed the following build warnings:

[auto build test WARNING on net-next/main]

url:    https://github.com/intel-lab-lkp/linux/commits/Kuniyuki-Iwashima/ipv6-Validate-RTA_GATEWAY-of-RTA_MULTIPATH-in-rtm_to_fib6_config/20250321-120836
base:   net-next/main
patch link:    https://lore.kernel.org/r/20250321040131.21057-11-kuniyu%40amazon.com
patch subject: [PATCH v1 net-next 10/13] ipv6: Factorise ip6_route_multipath_add().
:::::: branch date: 7 days ago
:::::: commit date: 7 days ago
config: i386-randconfig-141-20250328 (https://download.01.org/0day-ci/archive/20250328/202503282150.4vc017y0-lkp@intel.com/config)
compiler: clang version 20.1.1 (https://github.com/llvm/llvm-project 424c2d9b7e4de40d0804dd374721e6411c27d1d1)

If you fix the issue in a separate patch/commit (i.e. not just a new version of
the same patch/commit), kindly add following tags
| Reported-by: kernel test robot <lkp@intel.com>
| Reported-by: Dan Carpenter <error27@gmail.com>
| Closes: https://lore.kernel.org/r/202503282150.4vc017y0-lkp@intel.com/

New smatch warnings:
net/ipv6/route.c:5405 ip6_route_mpath_info_create_nh() error: uninitialized symbol 'err'.

Old smatch warnings:
net/ipv6/route.c:3427 ip6_route_check_nh() error: we previously assumed '_dev' could be null (see line 3387)
net/ipv6/route.c:5873 rt6_fill_node() error: we previously assumed 'dst' could be null (see line 5858)

vim +/err +5405 net/ipv6/route.c

f7d850c5de621f Kuniyuki Iwashima 2025-03-20  5374  
f7d850c5de621f Kuniyuki Iwashima 2025-03-20  5375  static int ip6_route_mpath_info_create_nh(struct list_head *rt6_nh_list,
f7d850c5de621f Kuniyuki Iwashima 2025-03-20  5376  					  struct netlink_ext_ack *extack)
f7d850c5de621f Kuniyuki Iwashima 2025-03-20  5377  {
f7d850c5de621f Kuniyuki Iwashima 2025-03-20  5378  	struct rt6_nh *nh, *nh_next, *nh_tmp;
f7d850c5de621f Kuniyuki Iwashima 2025-03-20  5379  	LIST_HEAD(tmp);
f7d850c5de621f Kuniyuki Iwashima 2025-03-20  5380  	int err;
f7d850c5de621f Kuniyuki Iwashima 2025-03-20  5381  
f7d850c5de621f Kuniyuki Iwashima 2025-03-20  5382  	list_for_each_entry_safe(nh, nh_next, rt6_nh_list, next) {
f7d850c5de621f Kuniyuki Iwashima 2025-03-20  5383  		struct fib6_info *rt = nh->fib6_info;
f7d850c5de621f Kuniyuki Iwashima 2025-03-20  5384  
f7d850c5de621f Kuniyuki Iwashima 2025-03-20  5385  		err = ip6_route_info_create_nh(rt, &nh->r_cfg, extack);
f7d850c5de621f Kuniyuki Iwashima 2025-03-20  5386  		if (err) {
f7d850c5de621f Kuniyuki Iwashima 2025-03-20  5387  			nh->fib6_info = NULL;
f7d850c5de621f Kuniyuki Iwashima 2025-03-20  5388  			goto err;
f7d850c5de621f Kuniyuki Iwashima 2025-03-20  5389  		}
f7d850c5de621f Kuniyuki Iwashima 2025-03-20  5390  
f7d850c5de621f Kuniyuki Iwashima 2025-03-20  5391  		rt->fib6_nh->fib_nh_weight = nh->weight;
f7d850c5de621f Kuniyuki Iwashima 2025-03-20  5392  
f7d850c5de621f Kuniyuki Iwashima 2025-03-20  5393  		list_move_tail(&nh->next, &tmp);
f7d850c5de621f Kuniyuki Iwashima 2025-03-20  5394  
f7d850c5de621f Kuniyuki Iwashima 2025-03-20  5395  		list_for_each_entry(nh_tmp, rt6_nh_list, next) {
f7d850c5de621f Kuniyuki Iwashima 2025-03-20  5396  			/* check if fib6_info already exists */
f7d850c5de621f Kuniyuki Iwashima 2025-03-20  5397  			if (rt6_duplicate_nexthop(nh_tmp->fib6_info, rt)) {
f7d850c5de621f Kuniyuki Iwashima 2025-03-20  5398  				err = -EEXIST;
f7d850c5de621f Kuniyuki Iwashima 2025-03-20  5399  				goto err;
f7d850c5de621f Kuniyuki Iwashima 2025-03-20  5400  			}
f7d850c5de621f Kuniyuki Iwashima 2025-03-20  5401  		}
f7d850c5de621f Kuniyuki Iwashima 2025-03-20  5402  	}
f7d850c5de621f Kuniyuki Iwashima 2025-03-20  5403  out:
f7d850c5de621f Kuniyuki Iwashima 2025-03-20  5404  	list_splice(&tmp, rt6_nh_list);
f7d850c5de621f Kuniyuki Iwashima 2025-03-20 @5405  	return err;
f7d850c5de621f Kuniyuki Iwashima 2025-03-20  5406  err:
f7d850c5de621f Kuniyuki Iwashima 2025-03-20  5407  	ip6_route_mpath_info_cleanup(rt6_nh_list);
f7d850c5de621f Kuniyuki Iwashima 2025-03-20  5408  	goto out;
6b9ea5a64ed5ee Roopa Prabhu      2015-09-08  5409  }
6b9ea5a64ed5ee Roopa Prabhu      2015-09-08  5410  

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