CC: [email protected]
CC: [email protected]
TO: Peter Zijlstra <[email protected]>

tree:   https://git.kernel.org/pub/scm/linux/kernel/git/torvalds/linux.git 
master
head:   6e764bcd1cf72a2846c0e53d3975a09b242c04c9
commit: 6e33cad0af49336952e5541464bd02f5b5fd433e sched: Trivial core scheduling 
cookie management
date:   4 months ago
:::::: branch date: 19 hours ago
:::::: commit date: 4 months ago
config: ia64-randconfig-s031-20210825 (attached as .config)
compiler: ia64-linux-gcc (GCC) 11.2.0
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: v0.6.3-348-gf0e6938b-dirty
        # 
https://git.kernel.org/pub/scm/linux/kernel/git/torvalds/linux.git/commit/?id=6e33cad0af49336952e5541464bd02f5b5fd433e
        git remote add linus 
https://git.kernel.org/pub/scm/linux/kernel/git/torvalds/linux.git
        git fetch --no-tags linus master
        git checkout 6e33cad0af49336952e5541464bd02f5b5fd433e
        # save the attached .config to linux build tree
        COMPILER_INSTALL_PATH=$HOME/0day COMPILER=gcc-11.2.0 make.cross C=1 
CF='-fdiagnostic-prefix -D__CHECK_ENDIAN__' O=build_dir ARCH=ia64 
SHELL=/bin/bash kernel/sched/

If you fix the issue, kindly add following tag as appropriate
Reported-by: kernel test robot <[email protected]>


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

6e33cad0af4933 Peter Zijlstra 2021-03-26  44  
6e33cad0af4933 Peter Zijlstra 2021-03-26  45  /*
6e33cad0af4933 Peter Zijlstra 2021-03-26  46   * sched_core_update_cookie - 
replace the cookie on a task
6e33cad0af4933 Peter Zijlstra 2021-03-26  47   * @p: the task to update
6e33cad0af4933 Peter Zijlstra 2021-03-26  48   * @cookie: the new cookie
6e33cad0af4933 Peter Zijlstra 2021-03-26  49   *
6e33cad0af4933 Peter Zijlstra 2021-03-26  50   * Effectively exchange the task 
cookie; caller is responsible for lifetimes on
6e33cad0af4933 Peter Zijlstra 2021-03-26  51   * both ends.
6e33cad0af4933 Peter Zijlstra 2021-03-26  52   *
6e33cad0af4933 Peter Zijlstra 2021-03-26  53   * Returns: the old cookie
6e33cad0af4933 Peter Zijlstra 2021-03-26  54   */
6e33cad0af4933 Peter Zijlstra 2021-03-26  55  unsigned long 
sched_core_update_cookie(struct task_struct *p, unsigned long cookie)
6e33cad0af4933 Peter Zijlstra 2021-03-26  56  {
6e33cad0af4933 Peter Zijlstra 2021-03-26  57    unsigned long old_cookie;
6e33cad0af4933 Peter Zijlstra 2021-03-26  58    struct rq_flags rf;
6e33cad0af4933 Peter Zijlstra 2021-03-26  59    struct rq *rq;
6e33cad0af4933 Peter Zijlstra 2021-03-26  60    bool enqueued;
6e33cad0af4933 Peter Zijlstra 2021-03-26  61  
6e33cad0af4933 Peter Zijlstra 2021-03-26  62    rq = task_rq_lock(p, &rf);
6e33cad0af4933 Peter Zijlstra 2021-03-26  63  
6e33cad0af4933 Peter Zijlstra 2021-03-26  64    /*
6e33cad0af4933 Peter Zijlstra 2021-03-26  65     * Since creating a cookie 
implies sched_core_get(), and we cannot set
6e33cad0af4933 Peter Zijlstra 2021-03-26  66     * a cookie until after we've 
created it, similarly, we cannot destroy
6e33cad0af4933 Peter Zijlstra 2021-03-26  67     * a cookie until after we've 
removed it, we must have core scheduling
6e33cad0af4933 Peter Zijlstra 2021-03-26  68     * enabled here.
6e33cad0af4933 Peter Zijlstra 2021-03-26  69     */
6e33cad0af4933 Peter Zijlstra 2021-03-26  70    SCHED_WARN_ON((p->core_cookie 
|| cookie) && !sched_core_enabled(rq));
6e33cad0af4933 Peter Zijlstra 2021-03-26  71  
6e33cad0af4933 Peter Zijlstra 2021-03-26  72    enqueued = 
sched_core_enqueued(p);
6e33cad0af4933 Peter Zijlstra 2021-03-26  73    if (enqueued)
6e33cad0af4933 Peter Zijlstra 2021-03-26  74            sched_core_dequeue(rq, 
p);
6e33cad0af4933 Peter Zijlstra 2021-03-26  75  
6e33cad0af4933 Peter Zijlstra 2021-03-26  76    old_cookie = p->core_cookie;
6e33cad0af4933 Peter Zijlstra 2021-03-26  77    p->core_cookie = cookie;
6e33cad0af4933 Peter Zijlstra 2021-03-26  78  
6e33cad0af4933 Peter Zijlstra 2021-03-26  79    if (enqueued)
6e33cad0af4933 Peter Zijlstra 2021-03-26  80            sched_core_enqueue(rq, 
p);
6e33cad0af4933 Peter Zijlstra 2021-03-26  81  
6e33cad0af4933 Peter Zijlstra 2021-03-26  82    /*
6e33cad0af4933 Peter Zijlstra 2021-03-26  83     * If task is currently 
running, it may not be compatible anymore after
6e33cad0af4933 Peter Zijlstra 2021-03-26  84     * the cookie change, so enter 
the scheduler on its CPU to schedule it
6e33cad0af4933 Peter Zijlstra 2021-03-26  85     * away.
6e33cad0af4933 Peter Zijlstra 2021-03-26  86     */
6e33cad0af4933 Peter Zijlstra 2021-03-26  87    if (task_running(rq, p))
6e33cad0af4933 Peter Zijlstra 2021-03-26  88            resched_curr(rq);
6e33cad0af4933 Peter Zijlstra 2021-03-26  89  
6e33cad0af4933 Peter Zijlstra 2021-03-26 @90    task_rq_unlock(rq, p, &rf);
6e33cad0af4933 Peter Zijlstra 2021-03-26  91  
6e33cad0af4933 Peter Zijlstra 2021-03-26  92    return old_cookie;
6e33cad0af4933 Peter Zijlstra 2021-03-26  93  }
6e33cad0af4933 Peter Zijlstra 2021-03-26  94  

---
0-DAY CI Kernel Test Service, Intel Corporation
https://lists.01.org/hyperkitty/list/[email protected]

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