Messages in this thread | | | From | Lai Jiangshan <> | Date | Thu, 28 Jul 2022 00:51:08 +0800 | Subject | Re: [PATCH] workqueue: avoid re-entry of pwq->pool->lock through __queue_work |
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On Wed, Jul 27, 2022 at 7:04 PM Kassey Li <quic_yingangl@quicinc.com> wrote: > > [0:swapper/4]BUG: spinlock recursion on CPU#4, swapper/4/0 > [0:swapper/4]lock: 0xffffff8000c0f400, .magic: dead4ead, .owner: > swapper/4/0, .owner_cpu: 4 > [0:swapper/4]CPU: 4 PID: 0 Comm: swapper/4 Tainted: G S > [0:swapper/4]Call trace: > [0:swapper/4] dump_backtrace.cfi_jt+0x0/0x8 > [0:swapper/4] show_stack+0x1c/0x2c > [0:swapper/4] dump_stack_lvl+0xd8/0x16c > [0:swapper/4] spin_dump+0x104/0x278 > [0:swapper/4] do_raw_spin_lock+0xec/0x15c > [0:swapper/4] _raw_spin_lock+0x28/0x3c > [0:swapper/4] __queue_work+0x1fc/0x618 > [0:swapper/4] queue_work_on+0x64/0x134 > [0:swapper/4] memlat_hrtimer_handler+0x28/0x3c [memlat] > [0:swapper/4] __run_hrtimer+0xe8/0x448 > [0:swapper/4] hrtimer_interrupt+0x184/0x40c > [0:swapper/4] arch_timer_handler_virt+0x5c/0x98 > [0:swapper/4] handle_percpu_devid_irq+0xd8/0x3e0 > [0:swapper/4] __handle_domain_irq+0xd0/0x19c > [0:swapper/4] gic_handle_irq+0x6c/0x134 > [0:swapper/4] el1_irq+0xe4/0x1c0
It seems it is an unexpected IRQ.
> [0:swapper/4] _raw_spin_unlock_irqrestore+0x2c/0x60 > [0:swapper/4] try_to_wake_up.llvm.14610847381734009831+0x334/0x888 > [0:swapper/4] wake_up_process+0x1c/0x2c > [0:swapper/4] __queue_work+0x3e8/0x618 > [0:swapper/4] delayed_work_timer_fn+0x24/0x34
delayed_work_timer_fn() should have been invoked with IRQ disabled since it is TIMER_IRQSAFE.
Could you add some code to check if it is the case if possible, please?
> [0:swapper/4] call_timer_fn+0x58/0x268 > [0:swapper/4] expire_timers+0xe0/0x1c4
Or could you do a "disass expire_timers+0xe0" in GDB?
> [0:swapper/4] __run_timers+0x16c/0x1c4 > [0:swapper/4] run_timer_softirq+0x34/0x60 > [0:swapper/4] efi_header_end+0x198/0x59c > [0:swapper/4] __irq_exit_rcu+0xdc/0xf0 > [0:swapper/4] irq_exit+0x14/0x50 > [0:swapper/4] __handle_domain_irq+0xd4/0x19c > [0:swapper/4] gic_handle_irq+0x6c/0x134 > [0:swapper/4] el1_irq+0xe4/0x1c0 > [0:swapper/4] cpuidle_enter_state+0x1b4/0x5dc > [0:swapper/4] cpuidle_enter+0x3c/0x58 > [0:swapper/4] do_idle.llvm.6296834828977863291+0x1f4/0x2e8 > [0:swapper/4] cpu_startup_entry+0x28/0x2c > [0:swapper/4] secondary_start_kernel+0x1c8/0x230 > > Signed-off-by: Kassey Li <quic_yingangl@quicinc.com> > --- > kernel/workqueue.c | 8 ++++---- > 1 file changed, 4 insertions(+), 4 deletions(-) > > diff --git a/kernel/workqueue.c b/kernel/workqueue.c > index 1ea50f6be843..f23491f373b1 100644 > --- a/kernel/workqueue.c > +++ b/kernel/workqueue.c > @@ -1468,10 +1468,10 @@ static void __queue_work(int cpu, struct workqueue_struct *wq, > } else { > /* meh... not running there, queue here */ > raw_spin_unlock(&last_pool->lock); > - raw_spin_lock(&pwq->pool->lock); > + raw_spin_lock_irq(&pwq->pool->lock); > } > } else { > - raw_spin_lock(&pwq->pool->lock); > + raw_spin_lock_irq(&pwq->pool->lock); > } > > /* > @@ -1484,7 +1484,7 @@ static void __queue_work(int cpu, struct workqueue_struct *wq, > */ > if (unlikely(!pwq->refcnt)) { > if (wq->flags & WQ_UNBOUND) { > - raw_spin_unlock(&pwq->pool->lock); > + raw_spin_unlock_irq(&pwq->pool->lock);
The patch is hardly correct, __queue_work() is called with irq-disabled, this code will enable IRQ imbalanced.
> cpu_relax(); > goto retry; > } > @@ -1517,7 +1517,7 @@ static void __queue_work(int cpu, struct workqueue_struct *wq, > insert_work(pwq, work, worklist, work_flags); > > out: > - raw_spin_unlock(&pwq->pool->lock); > + raw_spin_unlock_irq(&pwq->pool->lock); > rcu_read_unlock(); > } > > -- > 2.17.1 >
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