lkml.org 
[lkml]   [2017]   [Oct]   [19]   [last100]   RSS Feed
Views: [wrap][no wrap]   [headers]  [forward] 
 
Messages in this thread
    Patch in this message
    /
    From
    Subject[PATCH 4.9 17/51] sched/fair: Update rq clock before changing a tasks CPU affinity
    Date
    4.9-stable review patch.  If anyone has any objections, please let me know.

    ------------------

    From: Wanpeng Li <wanpeng.li@hotmail.com>


    [ Upstream commit a499c3ead88ccf147fc50689e85a530ad923ce36 ]

    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: Wanpeng Li <wanpeng.li@hotmail.com>
    Signed-off-by: Peter Zijlstra (Intel) <peterz@infradead.org>
    Reviewed-by: Matt 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.com
    Signed-off-by: Ingo Molnar <mingo@kernel.org>
    Signed-off-by: Sasha Levin <alexander.levin@verizon.com>
    Signed-off-by: Greg Kroah-Hartman <gregkh@linuxfoundation.org>
    ---
    kernel/sched/core.c | 1 +
    1 file changed, 1 insertion(+)

    --- a/kernel/sched/core.c
    +++ b/kernel/sched/core.c
    @@ -1141,6 +1141,7 @@ static int __set_cpus_allowed_ptr(struct
    int ret = 0;

    rq = task_rq_lock(p, &rf);
    + update_rq_clock(rq);

    if (p->flags & PF_KTHREAD) {
    /*

    \
     
     \ /
      Last update: 2017-10-22 17:26    [W:3.166 / U:1.168 seconds]
    ©2003-2020 Jasper Spaans|hosted at Digital Ocean and TransIP|Read the blog|Advertise on this site