From ab3d531745cf6cbbbf3a42679d50168d455dbbe4 Mon Sep 17 00:00:00 2001 From: Wanpeng Li Date: Tue, 21 Feb 2017 23:52:55 -0800 Subject: sched/fair: Update rq clock before changing a task's CPU affinity [ 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 Signed-off-by: Peter Zijlstra (Intel) Reviewed-by: Matt Fleming Cc: Linus Torvalds Cc: Mike Galbraith Cc: Peter Zijlstra Cc: Thomas Gleixner Link: http://lkml.kernel.org/r/1487749975-5994-1-git-send-email-wanpeng.li@hotmail.com Signed-off-by: Ingo Molnar Signed-off-by: Sasha Levin Signed-off-by: Greg Kroah-Hartman diff --git a/kernel/sched/core.c b/kernel/sched/core.c index d7dda36..02e7ad8 100644 --- a/kernel/sched/core.c +++ b/kernel/sched/core.c @@ -1141,6 +1141,7 @@ static int __set_cpus_allowed_ptr(struct task_struct *p, int ret = 0; rq = task_rq_lock(p, &rf); + update_rq_clock(rq); if (p->flags & PF_KTHREAD) { /* -- cgit v0.10.2