Messages in this thread Patch in this message | | | Date | Thu, 31 May 2018 05:29:03 -0700 | From | tip-bot for Juri Lelli <> | Subject | [tip:sched/urgent] sched/deadline: Fix missing clock update |
| |
Commit-ID: ecda2b66e263dfd6c1d6113add19150f4e235bb3 Gitweb: https://git.kernel.org/tip/ecda2b66e263dfd6c1d6113add19150f4e235bb3 Author: Juri Lelli <juri.lelli@redhat.com> AuthorDate: Wed, 30 May 2018 18:08:09 +0200 Committer: Ingo Molnar <mingo@kernel.org> CommitDate: Thu, 31 May 2018 12:27:13 +0200
sched/deadline: Fix missing clock update
A missing clock update is causing the following warning:
rq->clock_update_flags < RQCF_ACT_SKIP WARNING: CPU: 10 PID: 0 at kernel/sched/sched.h:963 inactive_task_timer+0x5d6/0x720 Call Trace: <IRQ> __hrtimer_run_queues+0x10f/0x530 hrtimer_interrupt+0xe5/0x240 smp_apic_timer_interrupt+0x79/0x2b0 apic_timer_interrupt+0xf/0x20 </IRQ> do_idle+0x203/0x280 cpu_startup_entry+0x6f/0x80 start_secondary+0x1b0/0x200 secondary_startup_64+0xa5/0xb0 hardirqs last enabled at (793919): [<ffffffffa27c5f6e>] cpuidle_enter_state+0x9e/0x360 hardirqs last disabled at (793920): [<ffffffffa2a0096e>] interrupt_entry+0xce/0xe0 softirqs last enabled at (793922): [<ffffffffa20bef78>] irq_enter+0x68/0x70 softirqs last disabled at (793921): [<ffffffffa20bef5d>] irq_enter+0x4d/0x70
This happens because inactive_task_timer() calls sub_running_bw() (if TASK_DEAD and non_contending) that might trigger a schedutil update, which might access the clock. Clock is however currently updated only later in inactive_task_timer() function.
Fix the problem by updating the clock right after task_rq_lock().
Reported-by: kernel test robot <xiaolong.ye@intel.com> Signed-off-by: Juri Lelli <juri.lelli@redhat.com> Signed-off-by: Peter Zijlstra (Intel) <peterz@infradead.org> Cc: Claudio Scordino <claudio@evidence.eu.com> Cc: Linus Torvalds <torvalds@linux-foundation.org> Cc: Luca Abeni <luca.abeni@santannapisa.it> Cc: Peter Zijlstra <peterz@infradead.org> Cc: Thomas Gleixner <tglx@linutronix.de> Link: http://lkml.kernel.org/r/20180530160809.9074-1-juri.lelli@redhat.com Signed-off-by: Ingo Molnar <mingo@kernel.org> --- kernel/sched/deadline.c | 6 +++--- 1 file changed, 3 insertions(+), 3 deletions(-)
diff --git a/kernel/sched/deadline.c b/kernel/sched/deadline.c index 1356afd1eeb6..fbfc3f1d368a 100644 --- a/kernel/sched/deadline.c +++ b/kernel/sched/deadline.c @@ -1259,6 +1259,9 @@ static enum hrtimer_restart inactive_task_timer(struct hrtimer *timer) rq = task_rq_lock(p, &rf); + sched_clock_tick(); + update_rq_clock(rq); + if (!dl_task(p) || p->state == TASK_DEAD) { struct dl_bw *dl_b = dl_bw_of(task_cpu(p)); @@ -1278,9 +1281,6 @@ static enum hrtimer_restart inactive_task_timer(struct hrtimer *timer) if (dl_se->dl_non_contending == 0) goto unlock; - sched_clock_tick(); - update_rq_clock(rq); - sub_running_bw(dl_se, &rq->dl); dl_se->dl_non_contending = 0; unlock:
| |