Am Samstag, 11. Juli 2020, 03:46:05 CEST schrieb John David Anglin: > Hi Jeroen, > > On 2020-07-10 6:50 p.m., Jeroen Roovers wrote: > > On Thu, 9 Jul 2020 09:39:33 -0400 > > > > John David Anglin <dave.anglin@xxxxxxxx> wrote: > >> On 2020-07-09 9:26 a.m., Rolf Eike Beer wrote: > >>> Am Freitag, 3. Juli 2020, 22:32:35 CEST schrieb John David Anglin: > >>>> Stalls are quite frequent with recent kernels. When the stall is > >>>> detected by rcu_sched, we get a backtrace similar to the > >>> > >>>> following: > >>> With this patch on top of 5.7.7 I still get: > >> Suggest enabling CONFIG_LOCKUP_DETECTOR=y and > >> CONFIG_SOFTLOCKUP_DETECTOR=y so we can see where the stall occurs. > >> > >> Dave > > > > Attached is kernel output while running the futex_requeue_pi test from > > the kernel selftests. It failed this way on the second try while it > > passed on the first try. The output it gave is with the kernel > > configuration options as set out above. > > Unfortunately, the soft lockup detector didn't trigger in the output you > attached. So, it's not clear where futex_requeue_p is stuck. There are no > spinlocks in check_preempt_curr() that I can see. Here is some info. Will use v2 patch soon. [835212.602791] watchdog: BUG: soft lockup - CPU#0 stuck for 21s! [cc1:4062] [835212.602791] Modules linked in: 8021q ipmi_poweroff ipmi_si ipmi_devintf sata_via ipmi_msghandler cbc dm_zero dm_snapshot dm_mirror dm_region_hash dm_log dm_crypt dm_bufio pata_sil680 libata [835212.602791] CPU: 0 PID: 4062 Comm: cc1 Tainted: G L 5.7.7- gentoo-parisc64 #2 [835212.602791] Hardware name: 9000/785/C8000 [835212.602791] [835212.602791] YZrvWESTHLNXBCVMcbcbcbcbOGFRQPDI [835212.602791] PSW: 00001000000001101111111100001111 Tainted: G L [835212.602791] r00-03 000000ff0806ff0f 0000000040a6a440 000000004035fcac 000000000096cf9a [835212.602791] r04-07 0000000040a36440 000000019ad27180 0000000230bc4488 0000000040c61250 [835212.602791] r08-11 0000000040dd29b0 0000000000000001 0000000000000030 0000000230bc48b0 [835212.602791] r12-15 0000000040dd3508 0000000000000000 0000000040a69c40 000000002ee74a64 [835212.602791] r16-19 00000001a64ec240 0000000040d42810 0000000002ae2b20 00000001a2feda71 [835212.602791] r20-23 00000002332bb090 0000000041fd1388 0000000001915c5f 000000019ad271c0 [835212.602791] r24-27 0000000230bc48b0 0000000230bc4488 00000001a64ec240 0000000040a36440 [835212.602791] r28-31 00000001a2feda71 0000000230bc49c0 0000000230bc49f0 000000000800000f [835212.602791] sr00-03 0000000003c7b800 0000000000000000 0000000000000000 0000000003c7b800 [835212.602791] sr04-07 0000000000000000 0000000000000000 0000000000000000 0000000000000000 [835212.602791] [835212.602791] IASQ: 0000000000000000 0000000000000000 IAOQ: 000000004035ff64 000000004035ff68 [835212.602791] IIR: 0d8010dc ISR: fffffffffffff000 IOR: 0000000040c619c8 [835212.602791] CPU: 0 CR30: 0000000230bc4000 CR31: ffffffffffffffff [835212.602791] ORIG_R28: 0000000040a69c40 [835212.602791] IAOQ[0]: d_alloc_parallel+0x424/0x668 [835212.602791] IAOQ[1]: d_alloc_parallel+0x428/0x668 [835212.602791] RP(r2): d_alloc_parallel+0x16c/0x668 [835212.602791] Backtrace: [835212.602791] [<000000004034a5f0>] __lookup_slow+0xb0/0x280 [835212.602791] [<000000004034c6a0>] walk_component+0x1d8/0x300 [835212.602791] [<000000004034cd88>] path_lookupat+0xd0/0x228 [835212.602791] [<000000004034fa64>] filename_lookup+0xac/0x1a8 [835212.602791] [<000000004034fccc>] user_path_at_empty+0x74/0x90 [835212.602791] [<000000004033c774>] vfs_statx+0xd4/0x1a0 [835212.602791] [<000000004033cdb8>] __do_sys_stat64+0x48/0xa0 [835212.602791] [<000000004033d5f0>] sys_stat64+0x20/0x30 [835212.602791] [<0000000040191018>] syscall_exit+0x0/0x14 [835212.602791] [835370.370791] rcu: INFO: rcu_sched self-detected stall on CPU [835370.370791] rcu: 0-....: (4817472 ticks this GP) idle=0c2/1/0x4000000000000002 softirq=71611784/71611784 fqs=56671 [835370.370791] (t=4965330 jiffies g=142820329 q=40783) [835370.370791] rcu: rcu_sched kthread starved for 4842124 jiffies! g142820329 f0x0 RCU_GP_WAIT_FQS(5) ->state=0x0 ->cpu=2 [835370.370791] rcu: RCU grace-period kthread stack dump: [835370.370791] rcu_sched R running task 0 10 2 0x00000000 [835370.370791] Backtrace: [835370.370791] [835370.370791] Task dump for CPU 0: [835370.370791] cc1 R running task 0 4062 4058 0x00000014 [835370.370791] Backtrace: [835370.370791] [<0000000040189a1c>] show_stack+0x5c/0x70 [835370.370791] [<0000000040201254>] sched_show_task.part.0+0x1a4/0x1c8 [835370.370791] [<00000000402014ac>] dump_cpu_task+0x8c/0xa8 [835370.370791] [<000000004024c858>] rcu_dump_cpu_stacks+0x168/0x210 [835370.370791] [<000000004024ad2c>] rcu_sched_clock_irq+0x984/0xd70 [835370.370791] [<0000000040251eb0>] update_process_times+0x80/0x110 [835370.370791] [<00000000409abdbc>] timer_interrupt+0xb4/0x130 [835370.370791] [<00000000402320c4>] __handle_irq_event_percpu+0xc4/0x270 [835370.370791] [<00000000402322a8>] handle_irq_event_percpu+0x38/0xd8 [835370.370791] [<000000004023a778>] handle_percpu_irq+0xb0/0xe8 [835370.370791] [<0000000040231140>] generic_handle_irq+0x50/0x60 [835370.370791] [<0000000040191304>] call_on_stack+0x18/0x24 [835370.370791] [<000000004018b728>] execute_on_irq_stack+0x80/0x98 [835370.370791] [<000000004018c928>] do_cpu_irq_mask+0x2a0/0x340 [835370.370791] [<0000000040190074>] intr_return+0x0/0xc [835370.370791] [835370.370791] Task dump for CPU 1: [835370.370791] cc1 R running task 0 4059 4055 0x00000014 [835370.370791] Backtrace: [835370.370791] [835370.370791] Task dump for CPU 3: [835370.370791] cc1 R running task 0 4061 4056 0x00000014 [835370.370791] Backtrace:
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