Re: [RFC PATCH 1/1] netlink: Add Netlink process event for cgroup migration

Re: [RFC PATCH 1/1] netlink: Add Netlink process event for cgroup migration

[kernel test robot]

Hi Prakash,

[This is a private test report for your RFC patch.]
kernel test robot noticed the following build errors:

[auto build test ERROR on tj-cgroup/for-next]
[also build test ERROR on net/main net-next/main linus/master v7.0 next-20260413]
[If your patch is applied to the wrong git tree, kindly drop us a note.
And when submitting patch, we suggest to use '--base' as documented in
https://git-scm.com/docs/git-format-patch#_base_tree_information]

url:    https://github.com/intel-lab-lkp/linux/commits/Prakash-Sangappa/netlink-Add-Netlink-process-event-for-cgroup-migration/20260413-212045
base:   https://git.kernel.org/pub/scm/linux/kernel/git/tj/cgroup.git for-next
patch link:    https://lore.kernel.org/r/20260407172339.2017158-2-prakash.sangappa%40oracle.com
patch subject: [RFC PATCH 1/1] netlink: Add Netlink process event for cgroup migration
config: hexagon-allmodconfig (https://download.01.org/0day-ci/archive/20260414/202604141600.VBaiiHS6-lkp@intel.com/config)
compiler: clang version 17.0.6 (https://github.com/llvm/llvm-project 6009708b4367171ccdbf4b5905cb6a803753fe18)
reproduce (this is a W=1 build): (https://download.01.org/0day-ci/archive/20260414/202604141600.VBaiiHS6-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/202604141600.VBaiiHS6-lkp@intel.com/

All errors (new ones prefixed by >>):

>> kernel/cgroup/cgroup.c:2985:3: error: call to undeclared function 'proc_cgroup_migrate_connector'; ISO C99 and later do not support implicit function declarations [-Wimplicit-function-declaration]
    2985 |                 proc_cgroup_migrate_connector(leader, dst_cgrp);
         |                 ^
   kernel/cgroup/cgroup.c:2985:3: note: did you mean 'proc_cgrp_migrate_connector'?
   include/linux/cn_proc.h:58:20: note: 'proc_cgrp_migrate_connector' declared here
      58 | static inline void proc_cgrp_migrate_connector(struct task_struct *task)
         |                    ^
   1 error generated.
--
>> kernel/cgroup/cgroup-v1.c:153:5: error: call to undeclared function 'proc_cgroup_migrate_connector'; ISO C99 and later do not support implicit function declarations [-Wimplicit-function-declaration]
     153 |                                 proc_cgroup_migrate_connector(task, to);
         |                                 ^
   kernel/cgroup/cgroup-v1.c:153:5: note: did you mean 'proc_cgrp_migrate_connector'?
   include/linux/cn_proc.h:58:20: note: 'proc_cgrp_migrate_connector' declared here
      58 | static inline void proc_cgrp_migrate_connector(struct task_struct *task)
         |                    ^
   1 error generated.


vim +/proc_cgroup_migrate_connector +2985 kernel/cgroup/cgroup.c

  2951	
  2952	/**
  2953	 * cgroup_attach_task - attach a task or a whole threadgroup to a cgroup
  2954	 * @dst_cgrp: the cgroup to attach to
  2955	 * @leader: the task or the leader of the threadgroup to be attached
  2956	 * @threadgroup: attach the whole threadgroup?
  2957	 *
  2958	 * Call holding cgroup_mutex and cgroup_threadgroup_rwsem.
  2959	 */
  2960	int cgroup_attach_task(struct cgroup *dst_cgrp, struct task_struct *leader,
  2961			       bool threadgroup)
  2962	{
  2963		DEFINE_CGROUP_MGCTX(mgctx);
  2964		struct task_struct *task;
  2965		int ret = 0;
  2966	
  2967		/* look up all src csets */
  2968		spin_lock_irq(&css_set_lock);
  2969		task = leader;
  2970		do {
  2971			cgroup_migrate_add_src(task_css_set(task), dst_cgrp, &mgctx);
  2972			if (!threadgroup)
  2973				break;
  2974		} while_each_thread(leader, task);
  2975		spin_unlock_irq(&css_set_lock);
  2976	
  2977		/* prepare dst csets and commit */
  2978		ret = cgroup_migrate_prepare_dst(&mgctx);
  2979		if (!ret)
  2980			ret = cgroup_migrate(leader, threadgroup, &mgctx);
  2981	
  2982		cgroup_migrate_finish(&mgctx);
  2983	
  2984		if (!ret) {
> 2985			proc_cgroup_migrate_connector(leader, dst_cgrp);
  2986			TRACE_CGROUP_PATH(attach_task, dst_cgrp, leader, threadgroup);
  2987		}
  2988	
  2989		return ret;
  2990	}
  2991	

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