rcu: INFO: rcu_preempt detected stalls on CPUs/tasks: rcu: Tasks blocked on level-0 rcu_node (CPUs 0-1): P7877/1:b..l rcu: (detected by 0, t=10502 jiffies, g=22517, q=3663 ncpus=2) task:syz.4.685 state:R running task stack:24656 pid:7877 tgid:7876 ppid:5828 flags:0x00004006 Call Trace: context_switch kernel/sched/core.c:5369 [inline] __schedule+0x1850/0x4c30 kernel/sched/core.c:6756 preempt_schedule_irq+0xfb/0x1c0 kernel/sched/core.c:7078 irqentry_exit+0x5e/0x90 kernel/entry/common.c:354 asm_sysvec_apic_timer_interrupt+0x1a/0x20 arch/x86/include/asm/idtentry.h:702 RIP: 0010:native_save_fl arch/x86/include/asm/irqflags.h:32 [inline] RIP: 0010:arch_local_save_flags arch/x86/include/asm/irqflags.h:87 [inline] RIP: 0010:arch_local_irq_save arch/x86/include/asm/irqflags.h:123 [inline] RIP: 0010:lock_release+0x198/0xa30 kernel/locking/lockdep.c:5866 Code: eb 03 42 80 3c 3b 00 74 08 4c 89 f7 e8 61 05 8b 00 4c 89 6c 24 50 48 c7 84 24 b0 00 00 00 00 00 00 00 9c 8f 84 24 b0 00 00 00 <42> 80 3c 3b 00 74 08 4c 89 f7 e8 49 04 8b 00 48 8b 9c 24 b0 00 00 RSP: 0018:ffffc90005237080 EFLAGS: 00000246 RAX: ffffffff93e14750 RBX: 1ffff92000a46e26 RCX: ffffffff817ad6a0 RDX: 0000000000000000 RSI: ffffffff8c5fb0c0 RDI: ffffffff8c5fb080 RBP: ffffc900052371b0 R08: ffffffff90197e77 R09: 1ffffffff2032fce R10: dffffc0000000000 R11: fffffbfff2032fcf R12: 1ffff92000a46e1c R13: ffffffff823e772b R14: ffffc90005237130 R15: dffffc0000000000 rcu_lock_release include/linux/rcupdate.h:347 [inline] rcu_read_unlock include/linux/rcupdate.h:880 [inline] proc_invalidate_siblings_dcache+0x36e/0x6e0 fs/proc/inode.c:128 proc_sys_invalidate_dcache fs/proc/proc_sysctl.c:289 [inline] start_unregistering fs/proc/proc_sysctl.c:316 [inline] drop_sysctl_table+0x1e1/0x570 fs/proc/proc_sysctl.c:1513 unregister_sysctl_table+0x41/0x60 fs/proc/proc_sysctl.c:1538 __devinet_sysctl_unregister net/ipv4/devinet.c:2653 [inline] devinet_sysctl_unregister net/ipv4/devinet.c:2681 [inline] inetdev_destroy net/ipv4/devinet.c:342 [inline] inetdev_event+0x846/0x1550 net/ipv4/devinet.c:1663 notifier_call_chain+0x1a7/0x3f0 kernel/notifier.c:85 call_netdevice_notifiers_extack net/core/dev.c:2034 [inline] call_netdevice_notifiers net/core/dev.c:2048 [inline] unregister_netdevice_many_notify+0xedd/0x1da0 net/core/dev.c:11526 unregister_netdevice_many net/core/dev.c:11590 [inline] unregister_netdevice_queue+0x303/0x370 net/core/dev.c:11462 unregister_netdevice include/linux/netdevice.h:3192 [inline] unregister_netdev+0x1c/0x30 net/core/dev.c:11608 slcan_close+0x78/0x140 drivers/net/can/slcan/slcan-core.c:866 tty_ldisc_kill+0xa3/0x1a0 drivers/tty/tty_ldisc.c:613 tty_ldisc_release+0x174/0x200 drivers/tty/tty_ldisc.c:781 tty_release_struct+0x2b/0xe0 drivers/tty/tty_io.c:1690 tty_release+0xd06/0x12c0 drivers/tty/tty_io.c:1861 __fput+0x23e/0xa50 fs/file_table.c:450 task_work_run+0x251/0x310 kernel/task_work.c:239 exit_task_work include/linux/task_work.h:43 [inline] do_exit+0xa2a/0x28e0 kernel/exit.c:938 do_group_exit+0x207/0x2c0 kernel/exit.c:1087 get_signal+0x16b2/0x1750 kernel/signal.c:3017 arch_do_signal_or_restart+0x96/0x860 arch/x86/kernel/signal.c:337 exit_to_user_mode_loop kernel/entry/common.c:111 [inline] exit_to_user_mode_prepare include/linux/entry-common.h:329 [inline] __syscall_exit_to_user_mode_work kernel/entry/common.c:207 [inline] syscall_exit_to_user_mode+0xce/0x340 kernel/entry/common.c:218 do_syscall_64+0x100/0x230 arch/x86/entry/common.c:89 entry_SYSCALL_64_after_hwframe+0x77/0x7f RIP: 0033:0x7fa39e385d29 RSP: 002b:00007fa39f1c50e8 EFLAGS: 00000246 ORIG_RAX: 00000000000000ca RAX: fffffffffffffe00 RBX: 00007fa39e575fa8 RCX: 00007fa39e385d29 RDX: 0000000000000000 RSI: 0000000000000080 RDI: 00007fa39e575fa8 RBP: 00007fa39e575fa0 R08: 0000000000000000 R09: 0000000000000000 R10: 0000000000000000 R11: 0000000000000246 R12: 00007fa39e575fac R13: 0000000000000000 R14: 00007fffa7d99b60 R15: 00007fffa7d99c48