[peterz-queue:sched/core-sched 21/24] kernel/sched/core_sched.c:90:23: sparse: sparse: context imbalance in 'sched_core_update_cookie' - wrong count at exit

[peterz-queue:sched/core-sched 21/24] kernel/sched/core_sched.c:90:23: sparse: sparse: context imbalance in 'sched_core_update_cookie' - wrong count at exit

[kernel test robot]

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CC: kbuild-all(a)lists.01.org
TO: Peter Zijlstra <peterz@infradead.org>

tree:   https://git.kernel.org/pub/scm/linux/kernel/git/peterz/queue.git sched/core-sched
head:   91ad025e6e8298578bf02fcb43e67b6b5fc4ce51
commit: 4ab9f5a371fdbaa0ece644ee83c06d551f2b7645 [21/24] sched: Trivial core scheduling cookie management
:::::: branch date: 9 hours ago
:::::: commit date: 9 hours ago
config: powerpc64-randconfig-s032-20210421 (attached as .config)
compiler: powerpc64le-linux-gcc (GCC) 9.3.0
reproduce:
        wget https://raw.githubusercontent.com/intel/lkp-tests/master/sbin/make.cross -O ~/bin/make.cross
        chmod +x ~/bin/make.cross
        # apt-get install sparse
        # sparse version: v0.6.3-341-g8af24329-dirty
        # https://git.kernel.org/pub/scm/linux/kernel/git/peterz/queue.git/commit/?id=4ab9f5a371fdbaa0ece644ee83c06d551f2b7645
        git remote add peterz-queue https://git.kernel.org/pub/scm/linux/kernel/git/peterz/queue.git
        git fetch --no-tags peterz-queue sched/core-sched
        git checkout 4ab9f5a371fdbaa0ece644ee83c06d551f2b7645
        # save the attached .config to linux build tree
        COMPILER_INSTALL_PATH=$HOME/0day COMPILER=gcc-9.3.0 make.cross C=1 CF='-fdiagnostic-prefix -D__CHECK_ENDIAN__' W=1 ARCH=powerpc64 

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


sparse warnings: (new ones prefixed by >>)
>> kernel/sched/core_sched.c:90:23: sparse: sparse: context imbalance in 'sched_core_update_cookie' - wrong count at exit

vim +/sched_core_update_cookie +90 kernel/sched/core_sched.c

4ab9f5a371fdba Peter Zijlstra 2021-03-26  44  
4ab9f5a371fdba Peter Zijlstra 2021-03-26  45  /*
4ab9f5a371fdba Peter Zijlstra 2021-03-26  46   * sched_core_update_cookie - replace the cookie on a task
4ab9f5a371fdba Peter Zijlstra 2021-03-26  47   * @p: the task to update
4ab9f5a371fdba Peter Zijlstra 2021-03-26  48   * @cookie: the new cookie
4ab9f5a371fdba Peter Zijlstra 2021-03-26  49   *
4ab9f5a371fdba Peter Zijlstra 2021-03-26  50   * Effectively exchange the task cookie; caller is responsible for lifetimes on
4ab9f5a371fdba Peter Zijlstra 2021-03-26  51   * both ends.
4ab9f5a371fdba Peter Zijlstra 2021-03-26  52   *
4ab9f5a371fdba Peter Zijlstra 2021-03-26  53   * Returns: the old cookie
4ab9f5a371fdba Peter Zijlstra 2021-03-26  54   */
4ab9f5a371fdba Peter Zijlstra 2021-03-26  55  unsigned long sched_core_update_cookie(struct task_struct *p, unsigned long cookie)
4ab9f5a371fdba Peter Zijlstra 2021-03-26  56  {
4ab9f5a371fdba Peter Zijlstra 2021-03-26  57  	unsigned long old_cookie;
4ab9f5a371fdba Peter Zijlstra 2021-03-26  58  	struct rq_flags rf;
4ab9f5a371fdba Peter Zijlstra 2021-03-26  59  	struct rq *rq;
4ab9f5a371fdba Peter Zijlstra 2021-03-26  60  	bool enqueued;
4ab9f5a371fdba Peter Zijlstra 2021-03-26  61  
4ab9f5a371fdba Peter Zijlstra 2021-03-26  62  	rq = task_rq_lock(p, &rf);
4ab9f5a371fdba Peter Zijlstra 2021-03-26  63  
4ab9f5a371fdba Peter Zijlstra 2021-03-26  64  	/*
4ab9f5a371fdba Peter Zijlstra 2021-03-26  65  	 * Since creating a cookie implies sched_core_get(), and we cannot set
4ab9f5a371fdba Peter Zijlstra 2021-03-26  66  	 * a cookie until after we've created it, similarly, we cannot destroy
4ab9f5a371fdba Peter Zijlstra 2021-03-26  67  	 * a cookie until after we've removed it, we must have core scheduling
4ab9f5a371fdba Peter Zijlstra 2021-03-26  68  	 * enabled here.
4ab9f5a371fdba Peter Zijlstra 2021-03-26  69  	 */
4ab9f5a371fdba Peter Zijlstra 2021-03-26  70  	SCHED_WARN_ON((p->core_cookie || cookie) && !sched_core_enabled(rq));
4ab9f5a371fdba Peter Zijlstra 2021-03-26  71  
4ab9f5a371fdba Peter Zijlstra 2021-03-26  72  	enqueued = sched_core_enqueued(p);
4ab9f5a371fdba Peter Zijlstra 2021-03-26  73  	if (enqueued)
4ab9f5a371fdba Peter Zijlstra 2021-03-26  74  		sched_core_dequeue(rq, p);
4ab9f5a371fdba Peter Zijlstra 2021-03-26  75  
4ab9f5a371fdba Peter Zijlstra 2021-03-26  76  	old_cookie = p->core_cookie;
4ab9f5a371fdba Peter Zijlstra 2021-03-26  77  	p->core_cookie = cookie;
4ab9f5a371fdba Peter Zijlstra 2021-03-26  78  
4ab9f5a371fdba Peter Zijlstra 2021-03-26  79  	if (enqueued)
4ab9f5a371fdba Peter Zijlstra 2021-03-26  80  		sched_core_enqueue(rq, p);
4ab9f5a371fdba Peter Zijlstra 2021-03-26  81  
4ab9f5a371fdba Peter Zijlstra 2021-03-26  82  	/*
4ab9f5a371fdba Peter Zijlstra 2021-03-26  83  	 * If task is currently running, it may not be compatible anymore after
4ab9f5a371fdba Peter Zijlstra 2021-03-26  84  	 * the cookie change, so enter the scheduler on its CPU to schedule it
4ab9f5a371fdba Peter Zijlstra 2021-03-26  85  	 * away.
4ab9f5a371fdba Peter Zijlstra 2021-03-26  86  	 */
4ab9f5a371fdba Peter Zijlstra 2021-03-26  87  	if (task_running(rq, p))
4ab9f5a371fdba Peter Zijlstra 2021-03-26  88  		resched_curr(rq);
4ab9f5a371fdba Peter Zijlstra 2021-03-26  89  
4ab9f5a371fdba Peter Zijlstra 2021-03-26 @90  	task_rq_unlock(rq, p, &rf);
4ab9f5a371fdba Peter Zijlstra 2021-03-26  91  
4ab9f5a371fdba Peter Zijlstra 2021-03-26  92  	return old_cookie;
4ab9f5a371fdba Peter Zijlstra 2021-03-26  93  }
4ab9f5a371fdba Peter Zijlstra 2021-03-26  94  

---
0-DAY CI Kernel Test Service, Intel Corporation
https://lists.01.org/hyperkitty/list/kbuild-all(a)lists.01.org

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