rcu: INFO: rcu_preempt self-detected stall on CPU rcu: 1-...!: (10499 ticks this GP) idle=b12/1/0x4000000000000002 softirq=10254/10254 fqs=41 (t=10500 jiffies g=5993 q=645) rcu: rcu_preempt kthread starved for 10415 jiffies! g5993 f0x0 RCU_GP_WAIT_FQS(5) ->state=0x0 ->cpu=0 rcu: RCU grace-period kthread stack dump: rcu_preempt R running task 29032 10 2 0x80004000 Call Trace: context_switch kernel/sched/core.c:3385 [inline] __schedule+0x9a0/0xcc0 kernel/sched/core.c:4081 schedule+0x181/0x210 kernel/sched/core.c:4155 schedule_timeout+0x14f/0x240 kernel/time/timer.c:1895 rcu_gp_fqs_loop kernel/rcu/tree.c:1661 [inline] rcu_gp_kthread+0xed8/0x1770 kernel/rcu/tree.c:1821 kthread+0x332/0x350 kernel/kthread.c:255 ret_from_fork+0x24/0x30 arch/x86/entry/entry_64.S:352 NMI backtrace for cpu 1 CPU: 1 PID: 8084 Comm: syz-executor.0 Not tainted 5.4.0-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+0x1fb/0x318 lib/dump_stack.c:118 nmi_cpu_backtrace+0xaf/0x1a0 lib/nmi_backtrace.c:101 nmi_trigger_cpumask_backtrace+0x174/0x290 lib/nmi_backtrace.c:62 arch_trigger_cpumask_backtrace+0x10/0x20 arch/x86/kernel/apic/hw_nmi.c:38 trigger_single_cpu_backtrace include/linux/nmi.h:164 [inline] rcu_dump_cpu_stacks+0x15a/0x220 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:2827 [inline] rcu_sched_clock_irq+0xe25/0x1ad0 kernel/rcu/tree.c:2271 update_process_times+0x12d/0x180 kernel/time/timer.c:1726 tick_sched_handle kernel/time/tick-sched.c:167 [inline] tick_sched_timer+0x263/0x420 kernel/time/tick-sched.c:1310 __run_hrtimer kernel/time/hrtimer.c:1514 [inline] __hrtimer_run_queues+0x403/0x840 kernel/time/hrtimer.c:1576 hrtimer_interrupt+0x38c/0xda0 kernel/time/hrtimer.c:1638 local_apic_timer_interrupt arch/x86/kernel/apic/apic.c:1110 [inline] smp_apic_timer_interrupt+0x109/0x280 arch/x86/kernel/apic/apic.c:1135 apic_timer_interrupt+0xf/0x20 arch/x86/entry/entry_64.S:829 RIP: 0010:mod_memcg_page_state+0x3d/0x190 include/linux/memcontrol.h:653 Code: 28 2e 00 48 83 c3 38 48 89 d8 48 c1 e8 03 49 bc 00 00 00 00 00 fc ff df 42 80 3c 20 00 74 08 48 89 df e8 b6 9f 69 00 48 8b 1b <48> 85 db 0f 84 d8 00 00 00 48 c7 c0 20 96 0a 89 48 c1 e8 03 42 80 RSP: 0018:ffffc900024d7588 EFLAGS: 00000246 ORIG_RAX: ffffffffffffff13 RAX: 1ffffd400051c73f RBX: 0000000000000000 RCX: 0000000000040000 RDX: ffffc90001f89000 RSI: 000000000003ffff RDI: 0000000000040000 RBP: ffffc900024d75a8 R08: 000000000003a768 R09: ffffed101306eeb7 R10: ffffed101306eeb7 R11: 0000000000000000 R12: dffffc0000000000 R13: dffffc0000000000 R14: 00000000fffffffc R15: ffff8880983775a8 free_thread_stack+0x168/0x590 kernel/fork.c:280 release_task_stack kernel/fork.c:440 [inline] put_task_stack+0xa3/0x130 kernel/fork.c:451 finish_task_switch+0x3f1/0x550 kernel/sched/core.c:3256 context_switch kernel/sched/core.c:3388 [inline] __schedule+0x9a8/0xcc0 kernel/sched/core.c:4081 preempt_schedule_irq+0xc1/0x140 kernel/sched/core.c:4338 retint_kernel+0x1b/0x2b RIP: 0010:arch_local_irq_restore arch/x86/include/asm/paravirt.h:752 [inline] RIP: 0010:slab_alloc mm/slab.c:3313 [inline] RIP: 0010:kmem_cache_alloc_trace+0x1ad/0x2f0 mm/slab.c:3549 Code: 8b 7d d0 57 9d 0f 1f 44 00 00 e8 3e aa ca ff eb 1e e8 d7 a7 ca ff 48 83 3d 37 09 59 07 00 0f 84 45 01 00 00 48 8b 7d d0 57 9d <0f> 1f 44 00 00 41 0f 18 0e e9 21 00 00 00 89 d8 c1 e8 08 83 e0 01 RSP: 0018:ffffc900024d7800 EFLAGS: 00000286 ORIG_RAX: ffffffffffffff02 RAX: ffff88806c7e48d4 RBX: 0000000000000dc0 RCX: ffffffff815c0597 RDX: 0000000000000000 RSI: 0000000000000008 RDI: 0000000000000286 RBP: ffffc900024d7840 R08: ffff88806c7e4898 R09: fffffbfff13c852d R10: fffffbfff13c852d R11: 0000000000000000 R12: 0000000000000dc0 R13: ffff8880aa800e00 R14: ffff8880985b2000 R15: ffff8880aa800e00 kmalloc include/linux/slab.h:556 [inline] kzalloc include/linux/slab.h:670 [inline] alloc_tty_struct+0x67/0x730 drivers/tty/tty_io.c:2980 pty_common_install+0x189/0x690 drivers/tty/pty.c:399 pty_unix98_install+0x1f/0x30 drivers/tty/pty.c:740 tty_driver_install_tty drivers/tty/tty_io.c:1228 [inline] tty_init_dev+0xd0/0x500 drivers/tty/tty_io.c:1341 ptmx_open+0xda/0x2d0 drivers/tty/pty.c:845 chrdev_open+0x509/0x590 fs/char_dev.c:414 do_dentry_open+0x740/0x10c0 fs/open.c:797 vfs_open+0x73/0x80 fs/open.c:914 do_last fs/namei.c:3412 [inline] path_openat+0x1397/0x44a0 fs/namei.c:3529 do_filp_open+0x192/0x3d0 fs/namei.c:3559 do_sys_open+0x29f/0x560 fs/open.c:1097 __do_sys_openat fs/open.c:1124 [inline] __se_sys_openat fs/open.c:1118 [inline] __x64_sys_openat+0xa2/0xb0 fs/open.c:1118 do_syscall_64+0xf7/0x1c0 arch/x86/entry/common.c:294 entry_SYSCALL_64_after_hwframe+0x49/0xbe RIP: 0033:0x45a679 Code: ad b6 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 7b b6 fb ff c3 66 2e 0f 1f 84 00 00 00 00 RSP: 002b:00007f3925336c78 EFLAGS: 00000246 ORIG_RAX: 0000000000000101 RAX: ffffffffffffffda RBX: 0000000000000004 RCX: 000000000045a679 RDX: 0000000000000000 RSI: 0000000020000000 RDI: ffffffffffffff9c RBP: 000000000075bf20 R08: 0000000000000000 R09: 0000000000000000 R10: 0000000000000000 R11: 0000000000000246 R12: 00007f39253376d4 R13: 00000000004c7edc R14: 00000000004df0e0 R15: 00000000ffffffff