FYI, we noticed the following commit (built with gcc-7): commit: f4dfad99bfe39733564e94ee520f902ae209705d ("sched/core: Prevent race condition between cpuset and __sched_setscheduler()") https://github.com/jlelli/linux.git fixes/deadline/root-domain-account-v7 in testcase: trinity with following parameters: runtime: 300s test-description: Trinity is a linux system call fuzz tester. test-url: http://codemonkey.org.uk/projects/trinity/ on test machine: qemu-system-i386 -enable-kvm -cpu SandyBridge -smp 2 -m 2G caused below changes (please refer to attached dmesg/kmsg for entire log/backtrace): +-------------------------------------------------+------------+------------+ | | c61fc953c4 | f4dfad99bf | +-------------------------------------------------+------------+------------+ | boot_successes | 5 | 0 | | boot_failures | 1 | 4 | | BUG:soft_lockup-CPU##stuck_for#s | 1 | 1 | | EIP:drm_mm_insert_node_in_range | 1 | 1 | | Kernel_panic-not_syncing:softlockup:hung_tasks | 1 | 1 | | WARNING:inconsistent_lock_state | 0 | 4 | | inconsistent{IN-HARDIRQ-W}->{HARDIRQ-ON-W}usage | 0 | 4 | +-------------------------------------------------+------------+------------+ [ 19.549992] WARNING: inconsistent lock state [ 19.549992] 5.1.0-rc1-00005-gf4dfad9 #113 Not tainted [ 19.549992] -------------------------------- [ 19.549992] inconsistent {IN-HARDIRQ-W} -> {HARDIRQ-ON-W} usage. [ 19.549992] swapper/1 [HC0[0]:SC0[0]:HE1:SE1] takes: [ 19.549992] (ptrval) (&rq->lock){?.-.}, at: __task_rq_lock+0x30/0x72 [ 19.549992] {IN-HARDIRQ-W} state was registered at: [ 19.549992] lock_acquire+0xe9/0x107 [ 19.549992] _raw_spin_lock+0x21/0x30 [ 19.549992] scheduler_tick+0x1d/0x95 [ 19.549992] update_process_times+0x34/0x37 [ 19.549992] tick_periodic+0x98/0xa4 [ 19.549992] tick_handle_periodic+0x13/0x4f [ 19.549992] timer_interrupt+0xf/0x16 [ 19.549992] __handle_irq_event_percpu+0xb5/0x1c2 [ 19.549992] handle_irq_event_percpu+0x19/0x3f [ 19.549992] handle_irq_event+0x29/0x42 [ 19.549992] handle_level_irq+0x88/0xb4 [ 19.549992] handle_irq+0x6b/0xb6 [ 19.549992] irq event stamp: 23 [ 19.549992] hardirqs last enabled at (23): [<41d69539>] _raw_spin_unlock_irq+0x22/0x2c [ 19.549992] hardirqs last disabled at (22): [<41d69384>] _raw_spin_lock_irq+0xc/0x36 [ 19.549992] softirqs last enabled at (18): [<41d6aeac>] __do_softirq+0x28c/0x2ba [ 19.549992] softirqs last disabled at (13): [<41005d27>] call_on_stack+0x40/0x46 [ 19.549992] [ 19.549992] other info that might help us debug this: [ 19.549992] Possible unsafe locking scenario: [ 19.549992] [ 19.549992] CPU0 [ 19.549992] ---- [ 19.549992] lock(&rq->lock); [ 19.549992] <Interrupt> [ 19.549992] lock(&rq->lock); [ 19.549992] [ 19.549992] *** DEADLOCK *** [ 19.549992] [ 19.549992] 1 lock held by swapper/1: [ 19.549992] #0: (ptrval) (&p->pi_lock){+.+.}, at: __sched_setscheduler+0xe8/0x52b [ 19.549992] [ 19.549992] stack backtrace: [ 19.549992] CPU: 0 PID: 1 Comm: swapper Not tainted 5.1.0-rc1-00005-gf4dfad9 #113 [ 19.549992] Call Trace: [ 19.549992] dump_stack+0x16/0x18 [ 19.549992] print_usage_bug+0x1f0/0x1fa [ 19.549992] mark_lock+0x32f/0x472 [ 19.549992] __lock_acquire+0x2f0/0xe2e [ 19.549992] ? __lock_acquire+0x20e/0xe2e [ 19.549992] lock_acquire+0xe9/0x107 [ 19.549992] ? __task_rq_lock+0x30/0x72 [ 19.549992] _raw_spin_lock+0x21/0x30 [ 19.549992] ? __task_rq_lock+0x30/0x72 [ 19.549992] __task_rq_lock+0x30/0x72 [ 19.549992] __sched_setscheduler+0xf2/0x52b [ 19.549992] _sched_setscheduler+0x68/0x70 [ 19.549992] sched_setscheduler_nocheck+0x1f/0x21 [ 19.549992] __kthread_create_on_node+0xfd/0x11e [ 19.549992] kthread_create_on_node+0x18/0x1a [ 19.549992] create_worker+0xa2/0x11e [ 19.549992] ? process_scheduled_works+0x22/0x22 [ 19.549992] workqueue_init+0x9d/0x102 [ 19.549992] ? rest_init+0x108/0x108 [ 19.549992] kernel_init_freeable+0x30/0x261 [ 19.549992] ? rest_init+0x108/0x108 [ 19.549992] kernel_init+0x8/0xd0 [ 19.549992] ret_from_fork+0x33/0x40 [ 19.582773] Performance Events: no PMU driver, software events only. [ 19.657957] NMI watchdog: Perf NMI watchdog permanently disabled [ 19.747678] devtmpfs: initialized [ 20.441420] clocksource: jiffies: mask: 0xffffffff max_cycles: 0xffffffff, max_idle_ns: 19112604462750000 ns [ 20.463487] futex hash table entries: 16 (order: -3, 704 bytes) [ 20.513740] xor: automatically using best checksumming function avx [ 20.531164] pinctrl core: initialized pinctrl subsystem [ 20.585967] regulator-dummy: no parameters [ 20.643658] NET: Registered protocol family 16 [ 20.856939] cpuidle: using governor ladder [ 21.135177] ACPI: bus type PCI registered [ 21.234115] PCI: PCI BIOS area is rw and x. Use pci=nobios if you want it NX. [ 21.252069] PCI: PCI BIOS revision 2.10 entry at 0xfd501, last bus=0 [ 21.281678] PCI: Using configuration type 1 for base access [ 21.670940] random: fast init done [ 22.118956] HugeTLB registered 2.00 MiB page size, pre-allocated 0 pages [ 22.183623] cryptd: max_cpu_qlen set to 1000 [ 22.410884] raid6: sse2x2 gen() 88 MB/s [ 22.601685] raid6: sse2x2 xor() 271 MB/s [ 22.792282] raid6: sse2x1 gen() 12 MB/s [ 22.981381] raid6: sse2x1 xor() 381 MB/s [ 23.172166] raid6: sse1x2 gen() 32 MB/s [ 23.362778] raid6: sse1x1 gen() 8 MB/s [ 23.370357] raid6: using algorithm sse2x2 gen() 88 MB/s [ 23.381153] raid6: .... xor() 271 MB/s, rmw enabled [ 23.390425] raid6: using ssse3x1 recovery algorithm [ 23.415221] gpio-f7188x: Not a Fintek device at 0x0000002e [ 23.434667] gpio-f7188x: Not a Fintek device at 0x0000004e [ 23.504128] ACPI: Added _OSI(Module Device) [ 23.521917] ACPI: Added _OSI(Processor Device) [ 23.541403] ACPI: Added _OSI(3.0 _SCP Extensions) [ 23.551537] ACPI: Added _OSI(Processor Aggregator Device) [ 23.583167] ACPI: Added _OSI(Linux-Dell-Video) [ 23.612856] ACPI: Added _OSI(Linux-Lenovo-NV-HDMI-Audio) [ 23.637000] ACPI: Added _OSI(Linux-HPI-Hybrid-Graphics) [ 23.833938] ACPI: 1 ACPI AML tables successfully acquired and loaded To reproduce: # build kernel cd linux cp config-5.1.0-rc1-00005-gf4dfad9 .config make HOSTCC=gcc-7 CC=gcc-7 ARCH=i386 olddefconfig make HOSTCC=gcc-7 CC=gcc-7 ARCH=i386 prepare make HOSTCC=gcc-7 CC=gcc-7 ARCH=i386 modules_prepare make HOSTCC=gcc-7 CC=gcc-7 ARCH=i386 SHELL=/bin/bash make HOSTCC=gcc-7 CC=gcc-7 ARCH=i386 bzImage git clone https://github.com/intel/lkp-tests.git cd lkp-tests bin/lkp qemu -k <bzImage> job-script # job-script is attached in this email Thanks, Rong Chen