rcu: INFO: rcu_preempt self-detected stall on CPU rcu: 1-...!: (1 GPs behind) idle=25a/1/0x4000000000000002 softirq=14548/14552 fqs=0 rcu: (t=10501 jiffies g=4365 q=27) rcu: rcu_preempt kthread starved for 10502 jiffies! g4365 f0x0 RCU_GP_WAIT_FQS(5) ->state=0x0 ->cpu=0 rcu: RCU grace-period kthread stack dump: rcu_preempt R running task 29760 10 2 0x80000000 Call Trace: context_switch kernel/sched/core.c:2828 [inline] __schedule+0x887/0x2040 kernel/sched/core.c:3517 schedule+0x8d/0x1b0 kernel/sched/core.c:3561 schedule_timeout+0x4cf/0xfe0 kernel/time/timer.c:1818 rcu_gp_kthread+0xdad/0x21c0 kernel/rcu/tree.c:2202 kthread+0x33f/0x460 kernel/kthread.c:259 ret_from_fork+0x24/0x30 arch/x86/entry/entry_64.S:415 NMI backtrace for cpu 1 CPU: 1 PID: 8183 Comm: syz-executor877 Not tainted 4.19.211-syzkaller #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+0x1fc/0x2ef lib/dump_stack.c:118 nmi_cpu_backtrace.cold+0x63/0xa2 lib/nmi_backtrace.c:101 nmi_trigger_cpumask_backtrace+0x1a6/0x1f0 lib/nmi_backtrace.c:62 trigger_single_cpu_backtrace include/linux/nmi.h:164 [inline] rcu_dump_cpu_stacks+0x15f/0x19c kernel/rcu/tree.c:1340 print_cpu_stall kernel/rcu/tree.c:1478 [inline] check_cpu_stall kernel/rcu/tree.c:1550 [inline] __rcu_pending kernel/rcu/tree.c:3293 [inline] rcu_pending kernel/rcu/tree.c:3336 [inline] rcu_check_callbacks.cold+0x62d/0xe19 kernel/rcu/tree.c:2682 update_process_times+0x2a/0x70 kernel/time/timer.c:1650 tick_sched_handle+0x9b/0x180 kernel/time/tick-sched.c:168 tick_sched_timer+0xfc/0x290 kernel/time/tick-sched.c:1278 __run_hrtimer kernel/time/hrtimer.c:1465 [inline] __hrtimer_run_queues+0x3f6/0xe60 kernel/time/hrtimer.c:1527 hrtimer_interrupt+0x326/0x9e0 kernel/time/hrtimer.c:1585 local_apic_timer_interrupt arch/x86/kernel/apic/apic.c:1071 [inline] smp_apic_timer_interrupt+0x10c/0x550 arch/x86/kernel/apic/apic.c:1096 apic_timer_interrupt+0xf/0x20 arch/x86/entry/entry_64.S:894 RIP: 0010:arch_local_irq_restore arch/x86/include/asm/paravirt.h:789 [inline] RIP: 0010:lock_acquire+0x1ec/0x3c0 kernel/locking/lockdep.c:3911 Code: 08 00 00 00 00 00 00 48 c1 e8 03 80 3c 10 00 0f 85 b7 01 00 00 48 83 3d 09 2e a6 08 00 0f 84 2a 01 00 00 48 8b 7c 24 08 57 9d <0f> 1f 44 00 00 48 83 c4 18 5b 5d 41 5c 41 5d 41 5e 41 5f c3 65 8b RSP: 0018:ffff888094d6f858 EFLAGS: 00000286 ORIG_RAX: ffffffffffffff13 RAX: 1ffffffff13e3051 RBX: ffff888094ce6680 RCX: 00000000000017d0 RDX: dffffc0000000000 RSI: 000000000eae4bec RDI: 0000000000000286 RBP: ffffffff89ff4d00 R08: ffffffff8cd233c0 R09: 0000000000000000 R10: ffff888094ce6f08 R11: 0000000000000000 R12: 0000000000000000 R13: 0000000000000000 R14: 0000000000000000 R15: 0000000000000001 __fs_reclaim_acquire mm/page_alloc.c:3759 [inline] fs_reclaim_acquire+0x105/0x130 mm/page_alloc.c:3770 slab_pre_alloc_hook mm/slab.h:419 [inline] slab_alloc mm/slab.c:3383 [inline] kmem_cache_alloc_trace+0x28/0x380 mm/slab.c:3623 kmalloc include/linux/slab.h:515 [inline] tty_alloc_file drivers/tty/tty_io.c:187 [inline] tty_open+0x138/0x990 drivers/tty/tty_io.c:2023 chrdev_open+0x266/0x770 fs/char_dev.c:423 do_dentry_open+0x4aa/0x1160 fs/open.c:796 do_last fs/namei.c:3421 [inline] path_openat+0x793/0x2df0 fs/namei.c:3537 do_filp_open+0x18c/0x3f0 fs/namei.c:3567 do_sys_open+0x3b3/0x520 fs/open.c:1085 do_syscall_64+0xf9/0x620 arch/x86/entry/common.c:293 entry_SYSCALL_64_after_hwframe+0x49/0xbe RIP: 0033:0x7f9856808af9 Code: 28 00 00 00 75 05 48 83 c4 28 c3 e8 11 15 00 00 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 73 01 c3 48 c7 c1 b8 ff ff ff f7 d8 64 89 01 48 RSP: 002b:00007f98567ba318 EFLAGS: 00000246 ORIG_RAX: 0000000000000101 RAX: ffffffffffffffda RBX: 00007f98568903e8 RCX: 00007f9856808af9 RDX: 0000000000000802 RSI: 0000000020000840 RDI: ffffffffffffff9c RBP: 00007f98568903e0 R08: 0000000000000000 R09: 0000000000000000 R10: 0000000000000000 R11: 0000000000000246 R12: 7974742f7665642f R13: 00007ffe867ea86f R14: 00007f98567ba400 R15: 0000000000022000 ---------------- Code disassembly (best guess): 0: 08 00 or %al,(%rax) 2: 00 00 add %al,(%rax) 4: 00 00 add %al,(%rax) 6: 00 48 c1 add %cl,-0x3f(%rax) 9: e8 03 80 3c 10 callq 0x103c8011 e: 00 0f add %cl,(%rdi) 10: 85 b7 01 00 00 48 test %esi,0x48000001(%rdi) 16: 83 3d 09 2e a6 08 00 cmpl $0x0,0x8a62e09(%rip) # 0x8a62e26 1d: 0f 84 2a 01 00 00 je 0x14d 23: 48 8b 7c 24 08 mov 0x8(%rsp),%rdi 28: 57 push %rdi 29: 9d popfq * 2a: 0f 1f 44 00 00 nopl 0x0(%rax,%rax,1) <-- trapping instruction 2f: 48 83 c4 18 add $0x18,%rsp 33: 5b pop %rbx 34: 5d pop %rbp 35: 41 5c pop %r12 37: 41 5d pop %r13 39: 41 5e pop %r14 3b: 41 5f pop %r15 3d: c3 retq 3e: 65 gs 3f: 8b .byte 0x8b