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Date:   Thu, 1 Jun 2023 22:33:52 +0800
From:   kernel test robot <lkp@intel.com>
To:     John Stultz <jstultz@google.com>,
        LKML <linux-kernel@vger.kernel.org>
Cc:     oe-kbuild-all@lists.linux.dev, Connor O'Brien <connoro@google.com>,
        Joel Fernandes <joelaf@google.com>,
        Qais Yousef <qyousef@google.com>,
        Ingo Molnar <mingo@redhat.com>,
        Peter Zijlstra <peterz@infradead.org>,
        Juri Lelli <juri.lelli@redhat.com>,
        Vincent Guittot <vincent.guittot@linaro.org>,
        Dietmar Eggemann <dietmar.eggemann@arm.com>,
        Valentin Schneider <vschneid@redhat.com>,
        Steven Rostedt <rostedt@goodmis.org>,
        Ben Segall <bsegall@google.com>,
        Zimuzo Ezeozue <zezeozue@google.com>,
        Youssef Esmat <youssefesmat@google.com>,
        Mel Gorman <mgorman@suse.de>,
        Daniel Bristot de Oliveira <bristot@redhat.com>,
        Will Deacon <will@kernel.org>,
        Waiman Long <longman@redhat.com>,
        Boqun Feng <boqun.feng@gmail.com>,
        "Paul E . McKenney" <paulmck@kernel.org>, kernel-team@android.com,
        John Stultz <jstultz@google.com>
Subject: Re: [PATCH v4 12/13] sched: Attempt to fix rt/dl load balancing via
 chain level balance
Message-ID: <202306011909.NWNswVmf-lkp@intel.com>
References: <20230601055846.2349566-13-jstultz@google.com>
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In-Reply-To: <20230601055846.2349566-13-jstultz@google.com>
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Hi John,

kernel test robot noticed the following build errors:

[auto build test ERROR on tip/sched/core]
[also build test ERROR on tip/locking/core tip/master tip/auto-latest linus/master v6.4-rc4 next-20230601]
[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/John-Stultz/sched-Unify-runtime-accounting-across-classes/20230601-140200
base:   tip/sched/core
patch link:    https://lore.kernel.org/r/20230601055846.2349566-13-jstultz%40google.com
patch subject: [PATCH v4 12/13] sched: Attempt to fix rt/dl load balancing via chain level balance
config: csky-randconfig-r016-20230531 (https://download.01.org/0day-ci/archive/20230601/202306011909.NWNswVmf-lkp@intel.com/config)
compiler: csky-linux-gcc (GCC) 12.3.0
reproduce (this is a W=1 build):
        mkdir -p ~/bin
        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/82593266398c6feaed3ed5ec458986d8e16b6b74
        git remote add linux-review https://github.com/intel-lab-lkp/linux
        git fetch --no-tags linux-review John-Stultz/sched-Unify-runtime-accounting-across-classes/20230601-140200
        git checkout 82593266398c6feaed3ed5ec458986d8e16b6b74
        # save the config file
        mkdir build_dir && cp config build_dir/.config
        COMPILER_INSTALL_PATH=$HOME/0day COMPILER=gcc-12.3.0 ~/bin/make.cross W=1 O=build_dir ARCH=csky olddefconfig
        COMPILER_INSTALL_PATH=$HOME/0day COMPILER=gcc-12.3.0 ~/bin/make.cross W=1 O=build_dir ARCH=csky SHELL=/bin/bash kernel/sched/

If you fix the issue, kindly add following tag where applicable
| Reported-by: kernel test robot <lkp@intel.com>
| Closes: https://lore.kernel.org/oe-kbuild-all/202306011909.NWNswVmf-lkp@intel.com/

All error/warnings (new ones prefixed by >>):

>> kernel/sched/core.c:3838:6: warning: no previous prototype for 'push_task_chain' [-Wmissing-prototypes]
    3838 | void push_task_chain(struct rq *rq, struct rq *dst_rq, struct task_struct *task)
         |      ^~~~~~~~~~~~~~~
   kernel/sched/core.c: In function 'push_task_chain':
>> kernel/sched/core.c:3858:42: error: 'struct rq' has no member named 'cpu'
    3858 |                 set_task_cpu(task, dst_rq->cpu);
         |                                          ^~
   kernel/sched/core.c: At top level:
>> kernel/sched/core.c:3870:21: warning: no previous prototype for 'find_exec_ctx' [-Wmissing-prototypes]
    3870 | struct task_struct *find_exec_ctx(struct rq *rq, struct task_struct *p)
         |                     ^~~~~~~~~~~~~
>> kernel/sched/core.c:3898:5: warning: no previous prototype for 'pushable_chain' [-Wmissing-prototypes]
    3898 | int pushable_chain(struct rq *rq, struct task_struct *p, int cpu)
         |     ^~~~~~~~~~~~~~


vim +3858 kernel/sched/core.c

  3837	
> 3838	void push_task_chain(struct rq *rq, struct rq *dst_rq, struct task_struct *task)
  3839	{
  3840		struct task_struct *owner;
  3841	
  3842		lockdep_assert_rq_held(rq);
  3843		lockdep_assert_rq_held(dst_rq);
  3844	
  3845		BUG_ON(!task_queued_on_rq(rq, task));
  3846		BUG_ON(task_current_selected(rq, task));
  3847	
  3848		while (task) {
  3849			if (!task_queued_on_rq(rq, task) || task_current_selected(rq, task))
  3850				break;
  3851	
  3852			if (task_is_blocked(task))
  3853				owner = __mutex_owner(task->blocked_on);
  3854			else
  3855				owner = NULL;
  3856	
  3857			deactivate_task(rq, task, 0);
> 3858			set_task_cpu(task, dst_rq->cpu);
  3859			activate_task(dst_rq, task, 0);
  3860			if (task == owner)
  3861				break;
  3862			task = owner;
  3863		}
  3864	}
  3865	
  3866	/*
  3867	 * Returns the unblocked task at the end of the blocked chain starting with p
  3868	 * if that chain is composed entirely of tasks enqueued on rq, or NULL otherwise.
  3869	 */
> 3870	struct task_struct *find_exec_ctx(struct rq *rq, struct task_struct *p)
  3871	{
  3872		struct task_struct *exec_ctx, *owner;
  3873		struct mutex *mutex;
  3874	
  3875		lockdep_assert_rq_held(rq);
  3876	
  3877		for (exec_ctx = p; task_is_blocked(exec_ctx) && !task_on_cpu(rq, exec_ctx);
  3878								exec_ctx = owner) {
  3879			mutex = exec_ctx->blocked_on;
  3880			owner = __mutex_owner(mutex);
  3881			if (owner == exec_ctx)
  3882				break;
  3883	
  3884			if (!task_queued_on_rq(rq, owner) || task_current_selected(rq, owner)) {
  3885				exec_ctx = NULL;
  3886				break;
  3887			}
  3888		}
  3889		return exec_ctx;
  3890	}
  3891	
  3892	/*
  3893	 * Returns:
  3894	 * 1 if chain is pushable and affinity does not prevent pushing to cpu
  3895	 * 0 if chain is unpushable
  3896	 * -1 if chain is pushable but affinity blocks running on cpu.
  3897	 */
> 3898	int pushable_chain(struct rq *rq, struct task_struct *p, int cpu)
  3899	{
  3900		struct task_struct *exec_ctx;
  3901	
  3902		lockdep_assert_rq_held(rq);
  3903	
  3904		if (task_rq(p) != rq || !task_on_rq_queued(p))
  3905			return 0;
  3906	
  3907		exec_ctx = find_exec_ctx(rq, p);
  3908		/*
  3909		 * Chain leads off the rq, we're free to push it anywhere.
  3910		 *
  3911		 * One wrinkle with relying on find_exec_ctx is that when the chain
  3912		 * leads to a task currently migrating to rq, we see the chain as
  3913		 * pushable & push everything prior to the migrating task. Even if
  3914		 * we checked explicitly for this case, we could still race with a
  3915		 * migration after the check.
  3916		 * This shouldn't permanently produce a bad state though, as proxy()
  3917		 * will send the chain back to rq and by that point the migration
  3918		 * should be complete & a proper push can occur.
  3919		 */
  3920		if (!exec_ctx)
  3921			return 1;
  3922	
  3923		if (task_on_cpu(rq, exec_ctx) || exec_ctx->nr_cpus_allowed <= 1)
  3924			return 0;
  3925	
  3926		return cpumask_test_cpu(cpu, &exec_ctx->cpus_mask) ? 1 : -1;
  3927	}
  3928	

-- 
0-DAY CI Kernel Test Service
https://github.com/intel/lkp-tests/wiki