FYI, we noticed the following commit (built with gcc-7): commit: 318b8acf18759b0a0c7fb1414d4901272061ed60 ("sched/fair: Add trivial fair server") https://git.kernel.org/cgit/linux/kernel/git/peterz/queue.git sched/wip-deadline 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 -smp 2 -m 8G caused below changes (please refer to attached dmesg/kmsg for entire log/backtrace): +----------------------------------+------------+------------+ | | 829381ea43 | 318b8acf18 | +----------------------------------+------------+------------+ | boot_successes | 0 | 0 | | boot_failures | 13 | 2 | | BUG:kernel_hang_in_boot_stage | 13 | | | BUG:kernel_timeout_in_boot_stage | 0 | 2 | +----------------------------------+------------+------------+ If you fix the issue, kindly add following tag Reported-by: kernel test robot <rong.a.chen(a)intel.com&gt; [ 16.477419] WARNING: CPU: 0 PID: 1 at kernel/sched/deadline.c:949 start_dl_timer+0x62/0x1f0 [ 16.480032] Modules linked in: [ 16.480914] CPU: 0 PID: 1 Comm: swapper/0 Not tainted 5.5.0-rc5-00065-g318b8acf18759 #16 [ 16.482007] Hardware name: QEMU Standard PC (i440FX + PIIX, 1996), BIOS 1.10.2-1 04/01/2014 [ 16.482007] RIP: 0010:start_dl_timer+0x62/0x1f0 [ 16.482007] Code: f8 83 e0 07 83 c0 03 38 d0 7c 09 84 d2 74 05 e8 ba 4c 31 00 83 3d b0 0d 89 04 00 74 0f 49 8d 7d 18 e8 da b5 ff ff 85 c0 75 02 <0f> 0b 48 8d 7b 48 48 b8 00 00 00 00 00 fc ff df 48 89 fa 48 c1 ea [ 16.482007] RSP: 0018:ffffc900000175b8 EFLAGS: 00010046 [ 16.482007] RAX: 0000000000000000 RBX: ffff8881f6ff4050 RCX: 1ffff1103ebfc900 [ 16.482007] RDX: 0000000000000000 RSI: ffff8881f6ff3698 RDI: ffff8881f5fe493c [ 16.482007] RBP: ffffc900000175d8 R08: fffffbfff0bf0b79 R09: 0000000000000001 [ 16.482007] R10: 0000000000000000 R11: ffffffff85f85bc7 R12: ffff8881f6ff3680 [ 16.482007] R13: ffff8881f6ff3680 R14: 000000000000a7a7 R15: ffffffffffe82f61 [ 16.482007] FS: 0000000000000000(0000) GS:ffff8881f6c00000(0000) knlGS:0000000000000000 [ 16.482007] CS: 0010 DS: 0000 ES: 0000 CR0: 0000000080050033 [ 16.482007] CR2: 00007ff943789000 CR3: 0000000004e16000 CR4: 00000000000406b0 [ 16.482007] DR0: 0000000000000000 DR1: 0000000000000000 DR2: 0000000000000000 [ 16.482007] DR3: 0000000000000000 DR6: 00000000fffe0ff0 DR7: 0000000000000400 [ 16.482007] Call Trace: [ 16.482007] update_curr_dl_se+0x33b/0x43f [ 16.482007] dl_server_update+0x47/0x4c [ 16.482007] update_curr+0x2e1/0x32a [ 16.482007] dequeue_entity+0x24/0x6f9 [ 16.482007] dequeue_task_fair+0x136/0x7e5 [ 16.482007] dequeue_task+0x1c2/0x1cd [ 16.482007] deactivate_task+0x117/0x120 [ 16.482007] __schedule+0x40b/0x1056 [ 16.482007] ? kasan_mem_notifier+0x200/0x200 [ 16.482007] schedule+0x1ac/0x215 [ 16.482007] schedule_timeout+0x86/0x1cb [ 16.482007] ? usleep_range+0x12c/0x12c [ 16.482007] ? lock_downgrade+0x598/0x598 [ 16.482007] ? __wait_for_common+0xad/0x3fb [ 16.482007] ? __kasan_check_read+0x11/0x13 [ 16.482007] ? atomic_read+0x19/0x49 [ 16.482007] ? trace_irq_enable_rcuidle+0x28/0x1a7 [ 16.482007] ? _raw_spin_unlock_irq+0x27/0x39 [ 16.482007] __wait_for_common+0x2ad/0x3fb [ 16.482007] ? usleep_range+0x12c/0x12c [ 16.482007] ? bit_wait_io_timeout+0xb9/0xb9 [ 16.482007] ? wake_up_q+0xa4/0xa4 [ 16.482007] ? __call_srcu+0x7d3/0x7e2 [ 16.482007] wait_for_completion+0x24/0x26 [ 16.482007] __synchronize_srcu+0x116/0x15d [ 16.482007] ? srcu_reschedule+0xf7/0xf7 [ 16.482007] ? rcu_read_lock_held_common+0x84/0x84 [ 16.482007] ? complete+0x1d/0x73 [ 16.482007] ? kvm_clock_read+0x18/0x28 [ 16.482007] ? kvm_clock_get_cycles+0x9/0xb [ 16.482007] synchronize_srcu_expedited+0x1f/0x21 [ 16.482007] ? synchronize_srcu_expedited+0x1f/0x21 [ 16.482007] synchronize_srcu+0x184/0x1a3 [ 16.482007] quarantine_remove_cache+0xe3/0x100 [ 16.482007] kasan_cache_shutdown+0x19/0x1c [ 16.482007] shutdown_cache+0x20/0x13d [ 16.482007] kmem_cache_destroy+0x19d/0x1ef [ 16.482007] test_meminit_init+0x564/0x993 [ 16.482007] ? fill_with_garbage+0xd/0xd [ 16.482007] ? fill_with_garbage+0xd/0xd [ 16.482007] do_one_initcall+0x197/0x3a2 [ 16.482007] ? perf_trace_initcall_level+0x2f1/0x2f1 [ 16.482007] ? __kasan_check_write+0x14/0x16 [ 16.482007] ? __kasan_check_read+0x11/0x13 [ 16.482007] ? test_bit+0x28/0x35 [ 16.482007] kernel_init_freeable+0x446/0x4c7 [ 16.482007] ? rest_init+0x120/0x120 [ 16.482007] kernel_init+0x11/0x119 [ 16.482007] ? rest_init+0x120/0x120 [ 16.482007] ret_from_fork+0x3a/0x50 [ 16.482007] _warn_unseeded_randomness: 349 callbacks suppressed [ 16.482007] random: get_random_bytes called from init_oops_id+0x26/0x37 with crng_init=0 [ 16.482007] ---[ end trace f7fec298ec961ada ]--- To reproduce: # build kernel cd linux cp config-5.5.0-rc5-00065-g318b8acf18759 .config make HOSTCC=gcc-7 CC=gcc-7 ARCH=x86_64 olddefconfig prepare modules_prepare 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