• W
    sched/fair: Update rq clock before changing a task's CPU affinity · a499c3ea
    Wanpeng Li 提交于
    This is triggered during boot when CONFIG_SCHED_DEBUG is enabled:
    
     ------------[ cut here ]------------
     WARNING: CPU: 6 PID: 81 at kernel/sched/sched.h:812 set_next_entity+0x11d/0x380
     rq->clock_update_flags < RQCF_ACT_SKIP
     CPU: 6 PID: 81 Comm: torture_shuffle Not tainted 4.10.0+ #1
     Hardware name: LENOVO ThinkCentre M8500t-N000/SHARKBAY, BIOS FBKTC1AUS 02/16/2016
     Call Trace:
      dump_stack+0x85/0xc2
      __warn+0xcb/0xf0
      warn_slowpath_fmt+0x5f/0x80
      set_next_entity+0x11d/0x380
      set_curr_task_fair+0x2b/0x60
      do_set_cpus_allowed+0x139/0x180
      __set_cpus_allowed_ptr+0x113/0x260
      set_cpus_allowed_ptr+0x10/0x20
      torture_shuffle+0xfd/0x180
      kthread+0x10f/0x150
      ? torture_shutdown_init+0x60/0x60
      ? kthread_create_on_node+0x60/0x60
      ret_from_fork+0x31/0x40
     ---[ end trace dd94d92344cea9c6 ]---
    
    The task is running && !queued, so there is no rq clock update before calling
    set_curr_task().
    
    This patch fixes it by updating rq clock after holding rq->lock/pi_lock
    just as what other dequeue + put_prev + enqueue + set_curr story does.
    Signed-off-by: NWanpeng Li <wanpeng.li@hotmail.com>
    Signed-off-by: NPeter Zijlstra (Intel) <peterz@infradead.org>
    Reviewed-by: NMatt Fleming <matt@codeblueprint.co.uk>
    Cc: Linus Torvalds <torvalds@linux-foundation.org>
    Cc: Mike Galbraith <efault@gmx.de>
    Cc: Peter Zijlstra <peterz@infradead.org>
    Cc: Thomas Gleixner <tglx@linutronix.de>
    Link: http://lkml.kernel.org/r/1487749975-5994-1-git-send-email-wanpeng.li@hotmail.comSigned-off-by: NIngo Molnar <mingo@kernel.org>
    a499c3ea
core.c 177.8 KB