Messages in this thread Patch in this message | | | Date | Thu, 28 Jul 2022 10:37:35 +0800 | Subject | Re: [PATCH] workqueue: avoid re-entry of pwq->pool->lock through __queue_work | From | Kassey Li <> |
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On 7/28/2022 12:51 AM, Lai Jiangshan wrote: > 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. thanks for your suggest, we will focus on the api usage of spin_lock where possible broken the irq enable/disable. currently, abandon this change. > >> [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? the timer flags = 0x15200004, which means TIMER_IRQSAFE is set. #define TIMER_IRQSAFE 0x00200000
> >> [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?
0xffffffc01025bf44 <+200>: tbz w8, #5, 0xffffffc01025bee4 <expire_timers+104> 0xffffffc01025bf48 <+204>: bl 0xffffffc0118093bc <_raw_spin_unlock> 0xffffffc01025bf4c <+208>: mov x0, x23 0xffffffc01025bf50 <+212>: mov x1, x24 0xffffffc01025bf54 <+216>: mov x2, x21 0xffffffc01025bf58 <+220>: bl 0xffffffc01025c040 <call_timer_fn> 0xffffffc01025bf5c <+224>: mov x0, x20 //expire_timers+0xe0 --Type <RET> for more, q to quit, c to continue without paging-- 0xffffffc01025bf60 <+228>: bl 0xffffffc011809230 <_raw_spin_lock> 0xffffffc01025bf64 <+232>: b 0xffffffc01025bf00 <expire_timers+132>
> >> [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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