NOHZ: local_softirq_pending 08 NOHZ: local_softirq_pending 08 NOHZ: local_softirq_pending 08 INFO: task syz-executor.1:10090 blocked for more than 140 seconds. Not tainted 4.14.180-syzkaller #0 "echo 0 > /proc/sys/kernel/hung_task_timeout_secs" disables this message. syz-executor.1 D27648 10090 6385 0x00000004 Call Trace: schedule+0x8d/0x1b0 kernel/sched/core.c:3428 schedule_timeout+0x946/0xe40 kernel/time/timer.c:1723 do_wait_for_common kernel/sched/completion.c:91 [inline] __wait_for_common kernel/sched/completion.c:112 [inline] wait_for_common kernel/sched/completion.c:123 [inline] wait_for_completion+0x241/0x390 kernel/sched/completion.c:144 _rcu_barrier+0x285/0x400 kernel/rcu/tree.c:3611 netdev_run_todo+0xed/0x710 net/core/dev.c:7913 tun_detach drivers/net/tun.c:587 [inline] tun_chr_close+0x46/0x60 drivers/net/tun.c:2671 __fput+0x25f/0x790 fs/file_table.c:210 task_work_run+0x113/0x190 kernel/task_work.c:113 tracehook_notify_resume include/linux/tracehook.h:191 [inline] exit_to_usermode_loop+0x1d6/0x220 arch/x86/entry/common.c:164 prepare_exit_to_usermode arch/x86/entry/common.c:199 [inline] syscall_return_slowpath arch/x86/entry/common.c:270 [inline] do_syscall_64+0x4a3/0x640 arch/x86/entry/common.c:297 entry_SYSCALL_64_after_hwframe+0x42/0xb7 RIP: 0033:0x416421 RSP: 002b:00007ffdf473f1b0 EFLAGS: 00000293 ORIG_RAX: 0000000000000003 RAX: 0000000000000000 RBX: 0000000000000006 RCX: 0000000000416421 RDX: 0000000000000000 RSI: 00000000000016af RDI: 0000000000000005 RBP: 0000000000000001 R08: 00000000aab9f6af R09: 00000000aab9f6b3 R10: 00007ffdf473f2a0 R11: 0000000000000293 R12: 000000000078c900 R13: 000000000078c900 R14: ffffffffffffffff R15: 000000000078bf0c Showing all locks held in the system: 1 lock held by khungtaskd/1057: #0: (tasklist_lock){.+.+}, at: [] debug_show_all_locks+0x7c/0x21a kernel/locking/lockdep.c:4548 1 lock held by khugepaged/1064: #0: (pcpu_drain_mutex){+.+.}, at: [] drain_all_pages+0x4a/0x570 mm/page_alloc.c:2493 2 locks held by agetty/6295: #0: (&tty->ldisc_sem){++++}, at: [] tty_ldisc_ref_wait+0x22/0x80 drivers/tty/tty_ldisc.c:284 #1: (&ldata->atomic_read_lock){+.+.}, at: [] n_tty_read+0x1e4/0x16f0 drivers/tty/n_tty.c:2156 1 lock held by syz-executor.1/10090: #0: (rcu_preempt_state.barrier_mutex){+.+.}, at: [] _rcu_barrier+0x56/0x400 kernel/rcu/tree.c:3546 ============================================= NMI backtrace for cpu 0 CPU: 0 PID: 1057 Comm: khungtaskd Not tainted 4.14.180-syzkaller #0 Hardware name: Google Google Compute Engine/Google Compute Engine, BIOS Google 01/01/2011 Call Trace: __dump_stack lib/dump_stack.c:17 [inline] dump_stack+0x13e/0x194 lib/dump_stack.c:58 nmi_cpu_backtrace.cold+0x57/0x93 lib/nmi_backtrace.c:101 nmi_trigger_cpumask_backtrace+0x139/0x17e lib/nmi_backtrace.c:62 trigger_all_cpu_backtrace include/linux/nmi.h:140 [inline] check_hung_uninterruptible_tasks kernel/hung_task.c:195 [inline] watchdog+0x5e2/0xb80 kernel/hung_task.c:274 kthread+0x30d/0x420 kernel/kthread.c:232 ret_from_fork+0x24/0x30 arch/x86/entry/entry_64.S:404 Sending NMI from CPU 0 to CPUs 1: NMI backtrace for cpu 1 CPU: 1 PID: 9902 Comm: syz-executor.4 Not tainted 4.14.180-syzkaller #0 Hardware name: Google Google Compute Engine/Google Compute Engine, BIOS Google 01/01/2011 task: ffff88805848c340 task.stack: ffff88804c6f0000 RIP: 0010:get_current arch/x86/include/asm/current.h:15 [inline] RIP: 0010:addr_limit_user_check include/linux/syscalls.h:240 [inline] RIP: 0010:prepare_exit_to_usermode+0x83/0x210 arch/x86/entry/common.c:189 RSP: 0000:ffff88804c6f7f38 EFLAGS: 00000046 RAX: 00007ffffffff000 RBX: ffff88805848c340 RCX: 0000000000000000 RDX: 1ffff1100b091af3 RSI: 1ffff110098defdc RDI: ffff88805848d798 RBP: ffff88804c6f7f58 R08: 0000000000000001 R09: 0000000000000000 R10: 0000000000000000 R11: 0000000000000000 R12: ffff88805848c340 R13: 0000000000000000 R14: 0000000000000000 R15: 0000000000000000 FS: 00007fe5e8505700(0000) GS:ffff8880aeb00000(0000) knlGS:0000000000000000 CS: 0010 DS: 0000 ES: 0000 CR0: 0000000080050033 CR2: 00000000353989e0 CR3: 000000008f9fd000 CR4: 00000000001406e0 DR0: 0000000000000000 DR1: 0000000000000000 DR2: 0000000000000000 DR3: 0000000000000000 DR6: 00000000fffe0ff0 DR7: 0000000000000400 Call Trace: retint_user+0x8/0x18 RIP: 0033:0x405be9 RSP: 002b:00007fe5e8504a70 EFLAGS: 00010202 RAX: 00000000353989d0 RBX: 0000000000508a20 RCX: 0000000000416687 RDX: 5b3766e45f25eb1c RSI: 0000000000000000 RDI: 0000000000000007 RBP: 000000000078c0e0 R08: 00007fe5e8504a70 R09: 000000000078c0e0 R10: 0000000000000000 R11: 0000000000000000 R12: 00000000ffffffff R13: 0000000000000bf9 R14: 00000000004ce1ea R15: 00007fe5e85056d4 Code: 00 00 48 89 fa 48 c1 ea 03 80 3c 02 00 0f 85 85 01 00 00 48 b8 00 f0 ff ff ff 7f 00 00 49 39 84 24 58 14 00 00 0f 85 e8 1c 00 00 a8 d9 59 00 65 48 8b 04 25 40 ee 01 00 f0 80 60 03 7f e8 95