On Thu, May 03, 2018 at 11:52:31PM +0800, kernel test robot wrote: > [ 0.011005] CPU: GenuineIntel Intel Core Processor (Haswell) (family: 0x6, > model: 0x3c, stepping: 0x4) > [ 0.012011] Spectre V2 : Spectre mitigation: kernel not compiled with > retpoline; no mitigation available! > [ 0.013949] Performance Events: no PMU driver, software events only. > [ 0.019490] NMI watchdog: Perf event create on CPU 0 failed with -2 > [ 0.020005] NMI watchdog: Perf NMI watchdog permanently disabled > [ 0.020692] WARNING: CPU: 0 PID: 1 at kernel/kthread.c:486 > kthread_park+0x2b/0x56 > [ 0.021000] CPU: 0 PID: 1 Comm: swapper Not tainted > 4.17.0-rc3-00038-g85f1abe #687 > [ 0.021000] Hardware name: QEMU Standard PC (i440FX + PIIX, 1996), BIOS > 1.10.2-1 04/01/2014 > [ 0.021000] EIP: kthread_park+0x2b/0x56 > [ 0.021000] EFLAGS: 00210202 CPU: 0 > [ 0.021000] EAX: cf464d40 EBX: cf422500 ECX: 00000000 EDX: 00000004 > [ 0.021000] ESI: c221e2c0 EDI: 00000000 EBP: cf42df68 ESP: cf42df60 > [ 0.021000] DS: 007b ES: 007b FS: 0000 GS: 00e0 SS: 0068 > [ 0.021000] CR0: 80050033 CR2: ffffffff CR3: 022e8000 CR4: 00140690 > [ 0.021000] DR0: 00000000 DR1: 00000000 DR2: 00000000 DR3: 00000000 > [ 0.021000] DR6: fffe0ff0 DR7: 00000400 > [ 0.021000] Call Trace: > [ 0.021000] smpboot_update_cpumask_percpu_thread+0x28/0x42 > [ 0.021000] softlockup_update_smpboot_threads+0x37/0x39 > [ 0.021000] lockup_detector_reconfigure+0x17/0x62 > [ 0.021000] lockup_detector_init+0x5d/0x69 > [ 0.021000] kernel_init_freeable+0x52/0x15c > [ 0.021000] ? rest_init+0xf4/0xf4 > [ 0.021000] kernel_init+0x8/0xd0 > [ 0.021000] ret_from_fork+0x19/0x30 > [ 0.021000] Code: 55 89 e5 56 53 8b 50 14 0f ba e2 15 72 02 0f 0b 8b 98 44 > 03 00 00 80 e2 04 74 09 0f 0b be da ff ff ff eb 2c 8b 13 80 e2 04 74 09 <0f> > 0b be f0 ff ff ff eb 1c 80 0b 04 8b 15 70 de f6 c1 31 f6 39 > [ 0.021000] ---[ end trace 3a71adb42feecba7 ]--- > [ 0.021060] TSC deadline timer enabled
Clearly my machine didn't do that :-) I think I see what's going on, this path actually does a kthread_park() when already parked, which sorta used to work. Let me try and fix that.
