Date:   Tue, 24 Jan 2023 03:01:41 +0800
From:   kernel test robot <lkp@intel.com>
To:     David Vernet <void@manifault.com>, bpf@vger.kernel.org
Cc:     oe-kbuild-all@lists.linux.dev, ast@kernel.org,
        daniel@iogearbox.net, andrii@kernel.org, martin.lau@linux.dev,
        song@kernel.org, yhs@meta.com, john.fastabend@gmail.com,
        kpsingh@kernel.org, sdf@google.com, haoluo@google.com,
        jolsa@kernel.org, linux-kernel@vger.kernel.org,
        kernel-team@meta.com, memxor@gmail.com
Subject: Re: [PATCH bpf-next v2 3/3] bpf: Use BPF_KFUNC macro at all kfunc
 definitions
Message-ID: <202301240220.RKx4Wgip-lkp@intel.com>
References: <20230123171506.71995-4-void@manifault.com>
MIME-Version: 1.0
Content-Type: text/plain; charset=iso-8859-1
Content-Disposition: inline
Content-Transfer-Encoding: 8bit
In-Reply-To: <20230123171506.71995-4-void@manifault.com>
Precedence: bulk

Hi David,

Thank you for the patch! Perhaps something to improve:

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

url:    https://github.com/intel-lab-lkp/linux/commits/David-Vernet/bpf-Add-BPF_KFUNC-macro-for-defining-kfuncs/20230124-011804
base:   https://git.kernel.org/pub/scm/linux/kernel/git/bpf/bpf-next.git master
patch link:    https://lore.kernel.org/r/20230123171506.71995-4-void%40manifault.com
patch subject: [PATCH bpf-next v2 3/3] bpf: Use BPF_KFUNC macro at all kfunc definitions
config: m68k-allyesconfig (https://download.01.org/0day-ci/archive/20230124/202301240220.RKx4Wgip-lkp@intel.com/config)
compiler: m68k-linux-gcc (GCC) 12.1.0
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
        # https://github.com/intel-lab-lkp/linux/commit/760b15a8e5d45d6e9925d2439e0d052de969b361
        git remote add linux-review https://github.com/intel-lab-lkp/linux
        git fetch --no-tags linux-review David-Vernet/bpf-Add-BPF_KFUNC-macro-for-defining-kfuncs/20230124-011804
        git checkout 760b15a8e5d45d6e9925d2439e0d052de969b361
        # save the config file
        mkdir build_dir && cp config build_dir/.config
        COMPILER_INSTALL_PATH=$HOME/0day COMPILER=gcc-12.1.0 make.cross W=1 O=build_dir ARCH=m68k olddefconfig
        COMPILER_INSTALL_PATH=$HOME/0day COMPILER=gcc-12.1.0 make.cross W=1 O=build_dir ARCH=m68k SHELL=/bin/bash kernel/ net/

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

All warnings (new ones prefixed by >>):

>> kernel/cgroup/rstat.c:30: warning: expecting prototype for cgroup_rstat_updated(). Prototype was for BPF_KFUNC() instead
>> kernel/cgroup/rstat.c:235: warning: expecting prototype for cgroup_rstat_flush(). Prototype was for BPF_KFUNC() instead
--
>> kernel/bpf/helpers.c:1850: warning: expecting prototype for bpf_task_acquire(). Prototype was for BPF_KFUNC() instead
>> kernel/bpf/helpers.c:1861: warning: expecting prototype for bpf_task_acquire_not_zero(). Prototype was for BPF_KFUNC() instead
>> kernel/bpf/helpers.c:1913: warning: expecting prototype for bpf_task_kptr_get(). Prototype was for BPF_KFUNC() instead
>> kernel/bpf/helpers.c:1926: warning: expecting prototype for bpf_task_release(). Prototype was for BPF_KFUNC() instead
>> kernel/bpf/helpers.c:1941: warning: expecting prototype for bpf_cgroup_acquire(). Prototype was for BPF_KFUNC() instead
>> kernel/bpf/helpers.c:1953: warning: expecting prototype for bpf_cgroup_kptr_get(). Prototype was for BPF_KFUNC() instead
>> kernel/bpf/helpers.c:1985: warning: expecting prototype for bpf_cgroup_release(). Prototype was for BPF_KFUNC() instead
>> kernel/bpf/helpers.c:2000: warning: expecting prototype for bpf_cgroup_ancestor(). Prototype was for BPF_KFUNC() instead
>> kernel/bpf/helpers.c:2019: warning: expecting prototype for bpf_task_from_pid(). Prototype was for BPF_KFUNC() instead
--
   net/bpf/test_run.c:490:14: warning: no previous prototype for 'bpf_fentry_test2' [-Wmissing-prototypes]
     490 | int noinline bpf_fentry_test2(int a, u64 b)
         |              ^~~~~~~~~~~~~~~~
   net/bpf/test_run.c:495:14: warning: no previous prototype for 'bpf_fentry_test3' [-Wmissing-prototypes]
     495 | int noinline bpf_fentry_test3(char a, int b, u64 c)
         |              ^~~~~~~~~~~~~~~~
   net/bpf/test_run.c:500:14: warning: no previous prototype for 'bpf_fentry_test4' [-Wmissing-prototypes]
     500 | int noinline bpf_fentry_test4(void *a, char b, int c, u64 d)
         |              ^~~~~~~~~~~~~~~~
   net/bpf/test_run.c:505:14: warning: no previous prototype for 'bpf_fentry_test5' [-Wmissing-prototypes]
     505 | int noinline bpf_fentry_test5(u64 a, void *b, short c, int d, u64 e)
         |              ^~~~~~~~~~~~~~~~
   net/bpf/test_run.c:510:14: warning: no previous prototype for 'bpf_fentry_test6' [-Wmissing-prototypes]
     510 | int noinline bpf_fentry_test6(u64 a, void *b, short c, int d, void *e, u64 f)
         |              ^~~~~~~~~~~~~~~~
>> net/bpf/test_run.c:519:14: warning: no previous prototype for 'bpf_fentry_test7' [-Wmissing-prototypes]
     519 | int noinline bpf_fentry_test7(struct bpf_fentry_test_t *arg)
         |              ^~~~~~~~~~~~~~~~
>> net/bpf/test_run.c:524:14: warning: no previous prototype for 'bpf_fentry_test8' [-Wmissing-prototypes]
     524 | int noinline bpf_fentry_test8(struct bpf_fentry_test_t *arg)
         |              ^~~~~~~~~~~~~~~~


vim +30 kernel/cgroup/rstat.c

041cd640b2f3c5 kernel/cgroup/stat.c  Tejun Heo       2017-09-25  19  
041cd640b2f3c5 kernel/cgroup/stat.c  Tejun Heo       2017-09-25  20  /**
6162cef0f741c7 kernel/cgroup/rstat.c Tejun Heo       2018-04-26  21   * cgroup_rstat_updated - keep track of updated rstat_cpu
041cd640b2f3c5 kernel/cgroup/stat.c  Tejun Heo       2017-09-25  22   * @cgrp: target cgroup
c58632b3631cb2 kernel/cgroup/rstat.c Tejun Heo       2018-04-26  23   * @cpu: cpu on which rstat_cpu was updated
041cd640b2f3c5 kernel/cgroup/stat.c  Tejun Heo       2017-09-25  24   *
c58632b3631cb2 kernel/cgroup/rstat.c Tejun Heo       2018-04-26  25   * @cgrp's rstat_cpu on @cpu was updated.  Put it on the parent's matching
c58632b3631cb2 kernel/cgroup/rstat.c Tejun Heo       2018-04-26  26   * rstat_cpu->updated_children list.  See the comment on top of
c58632b3631cb2 kernel/cgroup/rstat.c Tejun Heo       2018-04-26  27   * cgroup_rstat_cpu definition for details.
041cd640b2f3c5 kernel/cgroup/stat.c  Tejun Heo       2017-09-25  28   */
760b15a8e5d45d kernel/cgroup/rstat.c David Vernet    2023-01-23  29  BPF_KFUNC(void cgroup_rstat_updated(struct cgroup *cgrp, int cpu))
041cd640b2f3c5 kernel/cgroup/stat.c  Tejun Heo       2017-09-25 @30  {
c58632b3631cb2 kernel/cgroup/rstat.c Tejun Heo       2018-04-26  31  	raw_spinlock_t *cpu_lock = per_cpu_ptr(&cgroup_rstat_cpu_lock, cpu);
041cd640b2f3c5 kernel/cgroup/stat.c  Tejun Heo       2017-09-25  32  	unsigned long flags;
041cd640b2f3c5 kernel/cgroup/stat.c  Tejun Heo       2017-09-25  33  
041cd640b2f3c5 kernel/cgroup/stat.c  Tejun Heo       2017-09-25  34  	/*
d8ef4b38cb69d9 kernel/cgroup/rstat.c Tejun Heo       2020-04-09  35  	 * Speculative already-on-list test. This may race leading to
d8ef4b38cb69d9 kernel/cgroup/rstat.c Tejun Heo       2020-04-09  36  	 * temporary inaccuracies, which is fine.
d8ef4b38cb69d9 kernel/cgroup/rstat.c Tejun Heo       2020-04-09  37  	 *
041cd640b2f3c5 kernel/cgroup/stat.c  Tejun Heo       2017-09-25  38  	 * Because @parent's updated_children is terminated with @parent
041cd640b2f3c5 kernel/cgroup/stat.c  Tejun Heo       2017-09-25  39  	 * instead of NULL, we can tell whether @cgrp is on the list by
041cd640b2f3c5 kernel/cgroup/stat.c  Tejun Heo       2017-09-25  40  	 * testing the next pointer for NULL.
041cd640b2f3c5 kernel/cgroup/stat.c  Tejun Heo       2017-09-25  41  	 */
eda09706b240ca kernel/cgroup/rstat.c Michal Koutn?   2021-11-03  42  	if (data_race(cgroup_rstat_cpu(cgrp, cpu)->updated_next))
041cd640b2f3c5 kernel/cgroup/stat.c  Tejun Heo       2017-09-25  43  		return;
041cd640b2f3c5 kernel/cgroup/stat.c  Tejun Heo       2017-09-25  44  
041cd640b2f3c5 kernel/cgroup/stat.c  Tejun Heo       2017-09-25  45  	raw_spin_lock_irqsave(cpu_lock, flags);
041cd640b2f3c5 kernel/cgroup/stat.c  Tejun Heo       2017-09-25  46  
041cd640b2f3c5 kernel/cgroup/stat.c  Tejun Heo       2017-09-25  47  	/* put @cgrp and all ancestors on the corresponding updated lists */
dc26532aed0ab2 kernel/cgroup/rstat.c Johannes Weiner 2021-04-29  48  	while (true) {
c58632b3631cb2 kernel/cgroup/rstat.c Tejun Heo       2018-04-26  49  		struct cgroup_rstat_cpu *rstatc = cgroup_rstat_cpu(cgrp, cpu);
dc26532aed0ab2 kernel/cgroup/rstat.c Johannes Weiner 2021-04-29  50  		struct cgroup *parent = cgroup_parent(cgrp);
dc26532aed0ab2 kernel/cgroup/rstat.c Johannes Weiner 2021-04-29  51  		struct cgroup_rstat_cpu *prstatc;
041cd640b2f3c5 kernel/cgroup/stat.c  Tejun Heo       2017-09-25  52  
041cd640b2f3c5 kernel/cgroup/stat.c  Tejun Heo       2017-09-25  53  		/*
041cd640b2f3c5 kernel/cgroup/stat.c  Tejun Heo       2017-09-25  54  		 * Both additions and removals are bottom-up.  If a cgroup
041cd640b2f3c5 kernel/cgroup/stat.c  Tejun Heo       2017-09-25  55  		 * is already in the tree, all ancestors are.
041cd640b2f3c5 kernel/cgroup/stat.c  Tejun Heo       2017-09-25  56  		 */
c58632b3631cb2 kernel/cgroup/rstat.c Tejun Heo       2018-04-26  57  		if (rstatc->updated_next)
041cd640b2f3c5 kernel/cgroup/stat.c  Tejun Heo       2017-09-25  58  			break;
041cd640b2f3c5 kernel/cgroup/stat.c  Tejun Heo       2017-09-25  59  
dc26532aed0ab2 kernel/cgroup/rstat.c Johannes Weiner 2021-04-29  60  		/* Root has no parent to link it to, but mark it busy */
dc26532aed0ab2 kernel/cgroup/rstat.c Johannes Weiner 2021-04-29  61  		if (!parent) {
dc26532aed0ab2 kernel/cgroup/rstat.c Johannes Weiner 2021-04-29  62  			rstatc->updated_next = cgrp;
dc26532aed0ab2 kernel/cgroup/rstat.c Johannes Weiner 2021-04-29  63  			break;
dc26532aed0ab2 kernel/cgroup/rstat.c Johannes Weiner 2021-04-29  64  		}
dc26532aed0ab2 kernel/cgroup/rstat.c Johannes Weiner 2021-04-29  65  
dc26532aed0ab2 kernel/cgroup/rstat.c Johannes Weiner 2021-04-29  66  		prstatc = cgroup_rstat_cpu(parent, cpu);
c58632b3631cb2 kernel/cgroup/rstat.c Tejun Heo       2018-04-26  67  		rstatc->updated_next = prstatc->updated_children;
c58632b3631cb2 kernel/cgroup/rstat.c Tejun Heo       2018-04-26  68  		prstatc->updated_children = cgrp;
dc26532aed0ab2 kernel/cgroup/rstat.c Johannes Weiner 2021-04-29  69  
dc26532aed0ab2 kernel/cgroup/rstat.c Johannes Weiner 2021-04-29  70  		cgrp = parent;
041cd640b2f3c5 kernel/cgroup/stat.c  Tejun Heo       2017-09-25  71  	}
041cd640b2f3c5 kernel/cgroup/stat.c  Tejun Heo       2017-09-25  72  
041cd640b2f3c5 kernel/cgroup/stat.c  Tejun Heo       2017-09-25  73  	raw_spin_unlock_irqrestore(cpu_lock, flags);
041cd640b2f3c5 kernel/cgroup/stat.c  Tejun Heo       2017-09-25  74  }
041cd640b2f3c5 kernel/cgroup/stat.c  Tejun Heo       2017-09-25  75  

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