rcu: INFO: rcu_preempt self-detected stall on CPU rcu: 1-...!: (10500 ticks this GP) idle=03a/1/0x4000000000000004 softirq=62307/62307 fqs=0 (t=10501 jiffies g=108125 q=228) rcu: rcu_preempt kthread starved for 10502 jiffies! g108125 f0x0 RCU_GP_WAIT_FQS(5) ->state=0x0 ->cpu=1 rcu: RCU grace-period kthread stack dump: rcu_preempt R running task 28760 10 2 0x80004000 Call Trace: context_switch kernel/sched/core.c:3384 [inline] __schedule+0x7be/0x1b90 kernel/sched/core.c:4056 schedule+0xd9/0x260 kernel/sched/core.c:4123 schedule_timeout+0x486/0xc50 kernel/time/timer.c:1893 rcu_gp_fqs_loop kernel/rcu/tree.c:1639 [inline] rcu_gp_kthread+0x9b2/0x18c0 kernel/rcu/tree.c:1799 kthread+0x361/0x430 kernel/kthread.c:255 ret_from_fork+0x24/0x30 arch/x86/entry/entry_64.S:352 NMI backtrace for cpu 1 CPU: 1 PID: 2321 Comm: syz-executor.2 Not tainted 5.3.0+ #0 Hardware name: Google Google Compute Engine/Google Compute Engine, BIOS Google 01/01/2011 Call Trace: __dump_stack lib/dump_stack.c:77 [inline] dump_stack+0x172/0x1f0 lib/dump_stack.c:113 nmi_cpu_backtrace.cold+0x70/0xb2 lib/nmi_backtrace.c:101 nmi_trigger_cpumask_backtrace+0x23b/0x28b lib/nmi_backtrace.c:62 arch_trigger_cpumask_backtrace+0x14/0x20 arch/x86/kernel/apic/hw_nmi.c:38 trigger_single_cpu_backtrace include/linux/nmi.h:164 [inline] rcu_dump_cpu_stacks+0x183/0x1cf kernel/rcu/tree_stall.h:254 print_cpu_stall kernel/rcu/tree_stall.h:455 [inline] check_cpu_stall kernel/rcu/tree_stall.h:529 [inline] rcu_pending kernel/rcu/tree.c:2795 [inline] rcu_sched_clock_irq.cold+0x4fd/0xc0a kernel/rcu/tree.c:2244 update_process_times+0x2d/0x70 kernel/time/timer.c:1724 tick_sched_handle+0xa2/0x190 kernel/time/tick-sched.c:167 tick_sched_timer+0x53/0x140 kernel/time/tick-sched.c:1299 __run_hrtimer kernel/time/hrtimer.c:1514 [inline] __hrtimer_run_queues+0x364/0xe40 kernel/time/hrtimer.c:1576 hrtimer_interrupt+0x314/0x770 kernel/time/hrtimer.c:1638 local_apic_timer_interrupt arch/x86/kernel/apic/apic.c:1110 [inline] smp_apic_timer_interrupt+0x160/0x610 arch/x86/kernel/apic/apic.c:1135 apic_timer_interrupt+0xf/0x20 arch/x86/entry/entry_64.S:830 RIP: 0010:__raw_spin_unlock_irq include/linux/spinlock_api_smp.h:169 [inline] RIP: 0010:_raw_spin_unlock_irq+0x54/0x90 kernel/locking/spinlock.c:199 Code: c0 70 18 f3 88 48 ba 00 00 00 00 00 fc ff df 48 c1 e8 03 80 3c 10 00 75 33 48 83 3d 05 bf ac 01 00 74 20 fb 66 0f 1f 44 00 00 01 00 00 00 e8 e2 8f 08 fa 65 8b 05 83 a4 bb 78 85 c0 74 06 41 RSP: 0018:ffff8880ae909dd0 EFLAGS: 00000282 ORIG_RAX: ffffffffffffff13 RAX: 1ffffffff11e630e RBX: ffffffff85ccdd70 RCX: 0000000000000002 RDX: dffffc0000000000 RSI: 0000000000000008 RDI: ffff88805e9f2d94 RBP: ffff8880ae909dd8 R08: 1ffffffff14ef92c R09: fffffbfff14ef92d R10: fffffbfff14ef92c R11: ffffffff8a77c967 R12: ffff8880ae924c00 R13: ffff888097e52c88 R14: ffff8880ae924c00 R15: dffffc0000000000 expire_timers kernel/time/timer.c:1448 [inline] __run_timers kernel/time/timer.c:1771 [inline] __run_timers kernel/time/timer.c:1738 [inline] run_timer_softirq+0x6ae/0x17f0 kernel/time/timer.c:1784 __do_softirq+0x262/0x98c kernel/softirq.c:292 invoke_softirq kernel/softirq.c:373 [inline] irq_exit+0x19b/0x1e0 kernel/softirq.c:413 exiting_irq arch/x86/include/asm/apic.h:536 [inline] smp_apic_timer_interrupt+0x1a3/0x610 arch/x86/kernel/apic/apic.c:1137 apic_timer_interrupt+0xf/0x20 arch/x86/entry/entry_64.S:830 RIP: 0010:update_stack_state+0x334/0x5f0 arch/x86/kernel/unwind_frame.c:249 Code: 39 45 28 0f 84 3c 01 00 00 48 8d 75 98 4c 89 e7 e8 d1 fc ff ff 4c 8b 65 98 49 8d 7d 48 48 b8 00 00 00 00 00 fc ff df 48 89 f9 <48> c1 e9 03 80 3c 01 00 0f 85 47 02 00 00 4c 89 f9 4d 89 65 48 48 RSP: 0018:ffff888037a670a0 EFLAGS: 00000246 ORIG_RAX: ffffffffffffff13 RAX: dffffc0000000000 RBX: ffff888037a67ac0 RCX: ffff888037a67298 RDX: 0000000000000010 RSI: 1ffff11006f4ce00 RDI: ffff888037a67298 RBP: ffff888037a67168 R08: ffff88805e9f2500 R09: ffff888037a672a8 R10: ffff888037a67278 R11: ffff888037a67288 R12: ffffffff81bb15c9 R13: ffff888037a67250 R14: 1ffff11006f4ce1c R15: ffff888037a67290 unwind_next_frame.part.0+0x1a9/0xa20 arch/x86/kernel/unwind_frame.c:311 unwind_next_frame+0x3b/0x50 arch/x86/kernel/unwind_frame.c:265 arch_stack_walk+0x81/0xf0 arch/x86/kernel/stacktrace.c:25 stack_trace_save+0xac/0xe0 kernel/stacktrace.c:123 save_stack+0x23/0x90 mm/kasan/common.c:69 set_track mm/kasan/common.c:77 [inline] __kasan_kmalloc mm/kasan/common.c:493 [inline] __kasan_kmalloc.constprop.0+0xcf/0xe0 mm/kasan/common.c:466 kasan_slab_alloc+0xf/0x20 mm/kasan/common.c:501 slab_post_alloc_hook mm/slab.h:520 [inline] slab_alloc mm/slab.c:3319 [inline] __do_kmalloc mm/slab.c:3653 [inline] __kmalloc+0x14c/0x770 mm/slab.c:3664 kmalloc include/linux/slab.h:557 [inline] kzalloc include/linux/slab.h:748 [inline] apply_wqattrs_prepare+0xae/0x960 kernel/workqueue.c:3896 apply_workqueue_attrs_locked+0xcf/0x120 kernel/workqueue.c:4008 apply_workqueue_attrs+0x31/0x50 kernel/workqueue.c:4045 alloc_and_link_pwqs kernel/workqueue.c:4163 [inline] alloc_workqueue+0x9bc/0xf10 kernel/workqueue.c:4277 ucma_open+0x76/0x290 drivers/infiniband/core/ucma.c:1720 misc_open+0x395/0x4c0 drivers/char/misc.c:141 chrdev_open+0x245/0x6b0 fs/char_dev.c:414 do_dentry_open+0x4df/0x1250 fs/open.c:797 vfs_open+0xa0/0xd0 fs/open.c:906 do_last fs/namei.c:3408 [inline] path_openat+0x10e9/0x4630 fs/namei.c:3525 do_filp_open+0x1a1/0x280 fs/namei.c:3555 do_sys_open+0x3fe/0x5d0 fs/open.c:1089 __do_sys_openat fs/open.c:1116 [inline] __se_sys_openat fs/open.c:1110 [inline] __x64_sys_openat+0x9d/0x100 fs/open.c:1110 do_syscall_64+0xfa/0x760 arch/x86/entry/common.c:290 entry_SYSCALL_64_after_hwframe+0x49/0xbe RIP: 0033:0x459a09 Code: fd b7 fb ff c3 66 2e 0f 1f 84 00 00 00 00 00 66 90 48 89 f8 48 89 f7 48 89 d6 48 89 ca 4d 89 c2 4d 89 c8 4c 8b 4c 24 08 0f 05 <48> 3d 01 f0 ff ff 0f 83 cb b7 fb ff c3 66 2e 0f 1f 84 00 00 00 00 RSP: 002b:00007fbe98152c78 EFLAGS: 00000246 ORIG_RAX: 0000000000000101 RAX: ffffffffffffffda RBX: 0000000000000004 RCX: 0000000000459a09 RDX: 0000000000000002 RSI: 0000000020000580 RDI: ffffffffffffff9c RBP: 000000000075bf20 R08: 0000000000000000 R09: 0000000000000000 R10: 0000000000000000 R11: 0000000000000246 R12: 00007fbe981536d4 R13: 00000000004c645c R14: 00000000004db4b0 R15: 00000000ffffffff