FYI, we noticed the following commit: commit: 74239092337c458c622385cc2f6a4d12bb52d24e ("cgroup: Implement cgroup2 basic CPU usage accounting") https://git.kernel.org/cgit/linux/kernel/git/tj/cgroup.git review-cgroup2-cpu-basic-stat 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-x86_64 -enable-kvm -cpu SandyBridge -m 512M caused below changes (please refer to attached dmesg/kmsg for entire log/backtrace): +-------------------------------------------------------+------------+------------+ | | c0dee458e0 | 7423909233 | +-------------------------------------------------------+------------+------------+ | boot_successes | 4 | 2 | | boot_failures | 4 | 6 | | BUG:kernel_hang_in_test_stage | 4 | | | BUG:unable_to_handle_kernel | 0 | 6 | | Oops:#[##] | 0 | 6 | | Kernel_panic-not_syncing:Fatal_exception_in_interrupt | 0 | 6 | +-------------------------------------------------------+------------+------------+ [ 0.001380] BUG: unable to handle kernel NULL pointer dereference at 00000000000000e0 [ 0.002000] IP: account_system_index_time+0x12a/0x1af [ 0.002000] PGD 0 [ 0.002000] P4D 0 [ 0.002000] [ 0.002000] Oops: 0000 [#1] SMP [ 0.002000] Modules linked in: [ 0.002000] CPU: 0 PID: 0 Comm: swapper/0 Not tainted 4.13.0-rc1-00021-g7423909 #18 [ 0.002000] Hardware name: QEMU Standard PC (i440FX + PIIX, 1996), BIOS 1.9.3-20161025_171302-gandalf 04/01/2014 [ 0.002000] task: ffffffffab628500 task.stack: ffffffffab600000 [ 0.002000] RIP: 0010:account_system_index_time+0x12a/0x1af [ 0.002000] RSP: 0000:ffff96549f803c98 EFLAGS: 00010046 [ 0.002000] RAX: 0000000000000000 RBX: ffffffffab628500 RCX: 00000000fff649d9 [ 0.002000] RDX: ffffffffaa0cc24e RSI: 00000000ca811012 RDI: 0000000000000000 [ 0.002000] RBP: ffff96549f803cb8 R08: 00000002a7e04703 R09: 0000000000000001 [ 0.002000] R10: 0000000000000000 R11: 0000000000000068 R12: 00000000000f4240 [ 0.002000] R13: 0000000000000003 R14: ffffffffab68b940 R15: 0000000000000000 [ 0.002000] FS: 0000000000000000(0000) GS:ffff96549f800000(0000) knlGS:0000000000000000 [ 0.002000] CS: 0010 DS: 0000 ES: 0000 CR0: 0000000080050033 [ 0.002000] CR2: 00000000000000e0 CR3: 000000000e623000 CR4: 00000000000006b0 [ 0.002000] Call Trace: [ 0.002000] [ 0.002000] account_system_time+0x56/0x58 [ 0.002000] account_process_tick+0x7a/0xdb [ 0.002000] update_process_times+0x22/0x54 [ 0.002000] tick_periodic+0xa0/0xac [ 0.002000] tick_handle_periodic+0x25/0x66 [ 0.002000] timer_interrupt+0x15/0x1c [ 0.002000] __handle_irq_event_percpu+0xfd/0x309 [ 0.002000] handle_irq_event_percpu+0x20/0x4b [ 0.002000] handle_irq_event+0x38/0x56 [ 0.002000] handle_level_irq+0x9c/0xcd [ 0.002000] handle_irq+0xf0/0xfc [ 0.002000] do_IRQ+0x80/0xfc [ 0.002000] common_interrupt+0x93/0x93 [ 0.002000] RIP: 0010:native_irq_enable+0x6/0x7 [ 0.002000] RSP: 0000:ffff96549f803f38 EFLAGS: 00000202 ORIG_RAX: ffffffffffffffcf [ 0.002000] RAX: ffffffffab628500 RBX: 0000000000000002 RCX: 0000000000000000 [ 0.002000] RDX: ffff96549f803f34 RSI: ffffffffab628d98 RDI: ffffffffab628500 [ 0.002000] RBP: ffff96549f803fa0 R08: 00000002a7dc618a R09: 0000000000000001 [ 0.002000] R10: 0000000000000001 R11: 0000000000000068 R12: ffffffffab628500 [ 0.002000] R13: ffffffffab603d38 R14: ffff96549f432fd8 R15: 0000000000000001 [ 0.002000] ? __do_softirq+0x9e/0x43b [ 0.002000] irq_exit+0x5d/0xad [ 0.002000] do_IRQ+0xe4/0xfc [ 0.002000] common_interrupt+0x93/0x93 [ 0.002000] RIP: 0010:native_restore_fl+0x6/0x8 [ 0.002000] RSP: 0000:ffffffffab603de0 EFLAGS: 00000246 ORIG_RAX: ffffffffffffffcf [ 0.002000] RAX: ffffffffab628500 RBX: 0000000000000246 RCX: ffffffffab603d58 [ 0.002000] RDX: ffffffffaa08afce RSI: ffffffffab628d98 RDI: 0000000000000246 [ 0.002000] RBP: ffffffffab603de0 R08: 00000002a7cee657 R09: ffffffffab2689f8 [ 0.002000] R10: ffffffffab603c70 R11: 0000000000000002 R12: ffff96549f433080 [ 0.002000] R13: 0000000000000000 R14: 0000000000000000 R15: 0000000000000000 [ 0.002000] [ 0.002000] ? kvm_sched_clock_read+0x9/0x12 [ 0.002000] _raw_spin_unlock_irqrestore+0x52/0x5e [ 0.002000] __setup_irq+0x437/0x596 [ 0.002000] setup_irq+0x54/0x6f [ 0.002000] hpet_time_init+0x31/0x33 [ 0.002000] x86_late_time_init+0xf/0x16 [ 0.002000] start_kernel+0x35d/0x402 [ 0.002000] ? early_idt_handler_array+0x120/0x120 [ 0.002000] x86_64_start_reservations+0x24/0x26 [ 0.002000] x86_64_start_kernel+0x13b/0x14a [ 0.002000] secondary_startup_64+0x9f/0x9f [ 0.002000] Code: 17 cf 03 00 85 c0 75 1f 48 c7 c2 56 bc 24 ab be cf 01 00 00 48 c7 c7 89 59 26 ab c6 05 30 d7 5a 01 01 e8 53 d3 01 00 49 8b 7e 40 <48> 83 bf e0 00 00 00 00 75 6e e8 8a c9 03 00 85 c0 74 31 80 3d [ 0.002000] RIP: account_system_index_time+0x12a/0x1af RSP: ffff96549f803c98 [ 0.002000] CR2: 00000000000000e0 [ 0.002000] ---[ end trace be658dd14e22cef1 ]--- To reproduce: git clone https://github.com/01org/lkp-tests.git cd lkp-tests bin/lkp qemu -k job-script # job-script is attached in this email Thanks, Xiaolong