From: Phil Auld pauld@redhat.com
[ Upstream commit a46d14eca7b75fffe35603aa8b81df654353d80f ]
Enabling WARN_DOUBLE_CLOCK in /sys/kernel/debug/sched_features causes warning to fire in update_rq_clock. This seems to be caused by onlining a new fair sched group not using the rq lock wrappers.
[] rq->clock_update_flags & RQCF_UPDATED [] WARNING: CPU: 5 PID: 54385 at kernel/sched/core.c:210 update_rq_clock+0xec/0x150
[] Call Trace: [] online_fair_sched_group+0x53/0x100 [] cpu_cgroup_css_online+0x16/0x20 [] online_css+0x1c/0x60 [] cgroup_apply_control_enable+0x231/0x3b0 [] cgroup_mkdir+0x41b/0x530 [] kernfs_iop_mkdir+0x61/0xa0 [] vfs_mkdir+0x108/0x1a0 [] do_mkdirat+0x77/0xe0 [] do_syscall_64+0x55/0x1d0 [] entry_SYSCALL_64_after_hwframe+0x44/0xa9
Using the wrappers in online_fair_sched_group instead of the raw locking removes this warning.
[ tglx: Use rq_*lock_irq() ]
Signed-off-by: Phil Auld pauld@redhat.com Signed-off-by: Peter Zijlstra (Intel) peterz@infradead.org Signed-off-by: Thomas Gleixner tglx@linutronix.de Cc: Ingo Molnar mingo@redhat.com Cc: Vincent Guittot vincent.guittot@linaro.org Cc: Ingo Molnar mingo@kernel.org Link: https://lkml.kernel.org/r/20190801133749.11033-1-pauld@redhat.com Signed-off-by: Sasha Levin sashal@kernel.org --- kernel/sched/fair.c | 6 +++--- 1 file changed, 3 insertions(+), 3 deletions(-)
diff --git a/kernel/sched/fair.c b/kernel/sched/fair.c index 808db3566ddbc..55a33009f9a54 100644 --- a/kernel/sched/fair.c +++ b/kernel/sched/fair.c @@ -9423,18 +9423,18 @@ int alloc_fair_sched_group(struct task_group *tg, struct task_group *parent) void online_fair_sched_group(struct task_group *tg) { struct sched_entity *se; + struct rq_flags rf; struct rq *rq; int i;
for_each_possible_cpu(i) { rq = cpu_rq(i); se = tg->se[i]; - - raw_spin_lock_irq(&rq->lock); + rq_lock_irq(rq, &rf); update_rq_clock(rq); attach_entity_cfs_rq(se); sync_throttle(tg, i); - raw_spin_unlock_irq(&rq->lock); + rq_unlock_irq(rq, &rf); } }