Re: [PATCH bpf-next 2/6] bpf: Add syscall common attrs support for xdp link_create

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

Hi Leon,

kernel test robot noticed the following build errors:

[auto build test ERROR on bpf-next/master]

url:    https://github.com/intel-lab-lkp/linux/commits/Leon-Hwang/bpf-Add-syscall-common-attrs-support-for-link_create/20261017-222644
base:   https://git.kernel.org/pub/scm/linux/kernel/git/bpf/bpf-next.git master
patch link:    https://lore.kernel.org/r/20261017142649.51047-3-leon.hwang%40linux.dev
patch subject: [PATCH bpf-next 2/6] bpf: Add syscall common attrs support for xdp link_create
config: um-i386_defconfig (https://download.01.org/0day-ci/archive/20261018/202610181150.jL2DnHl7-lkp@intel.com/config)
compiler: gcc-14 (Debian 14.2.0-19) 14.2.0
reproduce (this is a W=1 build): (https://download.01.org/0day-ci/archive/20261018/202610181150.jL2DnHl7-lkp@intel.com/reproduce)

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>
| Closes: https://lore.kernel.org/oe-kbuild-all/202610181150.jL2DnHl7-lkp@intel.com/

All errors (new ones prefixed by >>):

   /usr/bin/ld: net/core/dev.o: in function `bpf_xdp_link_attach':
>> net/core/dev.c:10789:(.text+0x96f9): undefined reference to `bpf_log'
   collect2: error: ld returned 1 exit status


vim +10789 net/core/dev.c

 10774	
 10775	int bpf_xdp_link_attach(const union bpf_attr *attr, struct bpf_prog *prog,
 10776				struct bpf_verifier_log *log)
 10777	{
 10778		struct net *net = current->nsproxy->net_ns;
 10779		struct bpf_link_primer link_primer;
 10780		struct netlink_ext_ack extack = {};
 10781		struct bpf_xdp_link *link;
 10782		struct net_device *dev;
 10783		int err, fd;
 10784	
 10785		rtnl_lock();
 10786		dev = dev_get_by_index(net, attr->link_create.target_ifindex);
 10787		if (!dev) {
 10788			rtnl_unlock();
 10789			bpf_log(log, "Invalid target_ifindex.\n");
 10790			return -EINVAL;
 10791		}
 10792	
 10793		link = kzalloc_obj(*link, GFP_USER);
 10794		if (!link) {
 10795			err = -ENOMEM;
 10796			goto unlock;
 10797		}
 10798	
 10799		bpf_link_init(&link->link, BPF_LINK_TYPE_XDP, &bpf_xdp_link_lops, prog,
 10800			      attr->link_create.attach_type);
 10801		link->dev = dev;
 10802		link->flags = attr->link_create.flags;
 10803	
 10804		err = bpf_link_prime(&link->link, &link_primer);
 10805		if (err) {
 10806			kfree(link);
 10807			goto unlock;
 10808		}
 10809	
 10810		netdev_lock_ops(dev);
 10811		err = dev_xdp_attach_link(dev, &extack, link);
 10812		netdev_unlock_ops(dev);
 10813		rtnl_unlock();
 10814	
 10815		if (err) {
 10816			link->dev = NULL;
 10817			bpf_link_cleanup(&link_primer);
 10818			bpf_log(log, extack._msg);
 10819			trace_bpf_xdp_link_attach_failed(extack._msg);
 10820			goto out_put_dev;
 10821		}
 10822	
 10823		fd = bpf_link_settle(&link_primer);
 10824		/* link itself doesn't hold dev's refcnt to not complicate shutdown */
 10825		dev_put(dev);
 10826		return fd;
 10827	
 10828	unlock:
 10829		rtnl_unlock();
 10830	
 10831	out_put_dev:
 10832		dev_put(dev);
 10833		return err;
 10834	}
 10835	

--
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https://github.com/intel/lkp-tests/wiki