INFO: task syz-executor.0:20175 blocked for more than 140 seconds. Not tainted 4.14.158-syzkaller #0 "echo 0 > /proc/sys/kernel/hung_task_timeout_secs" disables this message. syz-executor.0 D28768 20175 7022 0x00000004 Call Trace: context_switch kernel/sched/core.c:2808 [inline] __schedule+0x7b8/0x1cd0 kernel/sched/core.c:3384 schedule+0x92/0x1c0 kernel/sched/core.c:3428 schedule_timeout+0x93b/0xe10 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+0x27c/0x420 kernel/sched/completion.c:144 flush_work+0x3eb/0x730 kernel/workqueue.c:2885 __cancel_work_timer+0x2f0/0x480 kernel/workqueue.c:2956 cancel_work_sync+0x18/0x20 kernel/workqueue.c:2992 p9_conn_destroy net/9p/trans_fd.c:873 [inline] p9_fd_close+0x2ae/0x450 net/9p/trans_fd.c:899 p9_client_create+0x787/0x1120 net/9p/client.c:1095 v9fs_session_init+0x1dc/0x1620 fs/9p/v9fs.c:422 v9fs_mount+0x7d/0x870 fs/9p/vfs_super.c:135 mount_fs+0x97/0x2a1 fs/super.c:1237 vfs_kern_mount.part.0+0x5e/0x3d0 fs/namespace.c:1046 vfs_kern_mount fs/namespace.c:1036 [inline] do_new_mount fs/namespace.c:2549 [inline] do_mount+0x417/0x27d0 fs/namespace.c:2879 SYSC_mount fs/namespace.c:3095 [inline] SyS_mount+0xab/0x120 fs/namespace.c:3072 do_syscall_64+0x1e8/0x640 arch/x86/entry/common.c:292 entry_SYSCALL_64_after_hwframe+0x42/0xb7 RIP: 0033:0x45a909 RSP: 002b:00007fe4b3985c78 EFLAGS: 00000246 ORIG_RAX: 00000000000000a5 RAX: ffffffffffffffda RBX: 0000000000000005 RCX: 000000000045a909 RDX: 0000000020000900 RSI: 0000000020000000 RDI: 0000000000000000 RBP: 000000000075bf20 R08: 00000000200004c0 R09: 0000000000000000 R10: 0000000000000000 R11: 0000000000000246 R12: 00007fe4b39866d4 R13: 00000000004c7cb8 R14: 00000000004deb40 R15: 00000000ffffffff Showing all locks held in the system: 2 locks held by kworker/1:1/23: #0: ("events"){+.+.}, at: [] work_static include/linux/workqueue.h:199 [inline] #0: ("events"){+.+.}, at: [] set_work_data kernel/workqueue.c:619 [inline] #0: ("events"){+.+.}, at: [] set_work_pool_and_clear_pending kernel/workqueue.c:646 [inline] #0: ("events"){+.+.}, at: [] process_one_work+0x76e/0x1600 kernel/workqueue.c:2085 #1: ((&m->wq)){+.+.}, at: [] process_one_work+0x7ab/0x1600 kernel/workqueue.c:2089 1 lock held by khungtaskd/1044: #0: (tasklist_lock){.+.+}, at: [] debug_show_all_locks+0x7f/0x21f kernel/locking/lockdep.c:4544 1 lock held by rsyslogd/6852: #0: (&f->f_pos_lock){+.+.}, at: [] __fdget_pos+0xab/0xd0 fs/file.c:769 2 locks held by getty/6974: #0: (&tty->ldisc_sem){++++}, at: [] ldsem_down_read+0x33/0x40 drivers/tty/tty_ldsem.c:376 #1: (&ldata->atomic_read_lock){+.+.}, at: [] n_tty_read+0x1e6/0x17b0 drivers/tty/n_tty.c:2156 2 locks held by getty/6975: #0: (&tty->ldisc_sem){++++}, at: [] ldsem_down_read+0x33/0x40 drivers/tty/tty_ldsem.c:376 #1: (&ldata->atomic_read_lock){+.+.}, at: [] n_tty_read+0x1e6/0x17b0 drivers/tty/n_tty.c:2156 2 locks held by getty/6976: #0: (&tty->ldisc_sem){++++}, at: [] ldsem_down_read+0x33/0x40 drivers/tty/tty_ldsem.c:376 #1: (&ldata->atomic_read_lock){+.+.}, at: [] n_tty_read+0x1e6/0x17b0 drivers/tty/n_tty.c:2156 2 locks held by getty/6977: #0: (&tty->ldisc_sem){++++}, at: [] ldsem_down_read+0x33/0x40 drivers/tty/tty_ldsem.c:376 #1: (&ldata->atomic_read_lock){+.+.}, at: [] n_tty_read+0x1e6/0x17b0 drivers/tty/n_tty.c:2156 2 locks held by getty/6978: #0: (&tty->ldisc_sem){++++}, at: [] ldsem_down_read+0x33/0x40 drivers/tty/tty_ldsem.c:376 #1: (&ldata->atomic_read_lock){+.+.}, at: [] n_tty_read+0x1e6/0x17b0 drivers/tty/n_tty.c:2156 2 locks held by getty/6979: #0: (&tty->ldisc_sem){++++}, at: [] ldsem_down_read+0x33/0x40 drivers/tty/tty_ldsem.c:376 #1: (&ldata->atomic_read_lock){+.+.}, at: [] n_tty_read+0x1e6/0x17b0 drivers/tty/n_tty.c:2156 2 locks held by getty/6980: #0: (&tty->ldisc_sem){++++}, at: [] ldsem_down_read+0x33/0x40 drivers/tty/tty_ldsem.c:376 #1: (&ldata->atomic_read_lock){+.+.}, at: [] n_tty_read+0x1e6/0x17b0 drivers/tty/n_tty.c:2156 ============================================= NMI backtrace for cpu 1 CPU: 1 PID: 1044 Comm: khungtaskd Not tainted 4.14.158-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+0x142/0x197 lib/dump_stack.c:58 nmi_cpu_backtrace.cold+0x57/0x94 lib/nmi_backtrace.c:101 nmi_trigger_cpumask_backtrace+0x141/0x189 lib/nmi_backtrace.c:62 arch_trigger_cpumask_backtrace+0x14/0x20 arch/x86/kernel/apic/hw_nmi.c:38 trigger_all_cpu_backtrace include/linux/nmi.h:140 [inline] check_hung_uninterruptible_tasks kernel/hung_task.c:195 [inline] watchdog+0x5e7/0xb90 kernel/hung_task.c:274 kthread+0x319/0x430 kernel/kthread.c:232 ret_from_fork+0x24/0x30 arch/x86/entry/entry_64.S:404 Sending NMI from CPU 1 to CPUs 0: NMI backtrace for cpu 0 CPU: 0 PID: 2308 Comm: kworker/u4:3 Not tainted 4.14.158-syzkaller #0 Hardware name: Google Google Compute Engine/Google Compute Engine, BIOS Google 01/01/2011 Workqueue: bat_events batadv_nc_worker task: ffff8880a18fe340 task.stack: ffff8880a1970000 RIP: 0010:__sanitizer_cov_trace_pc+0x23/0x60 kernel/kcov.c:68 RSP: 0018:ffff8880a1977c78 EFLAGS: 00000246 RAX: ffff8880a18fe340 RBX: ffff8880a124fd80 RCX: 1ffffffff1066f80 RDX: 0000000000000000 RSI: ffffffff87040c80 RDI: ffffffff87040cc0 RBP: ffff8880a1977cb0 R08: 0000000000000000 R09: ffff8880a18fec30 R10: ffff8880a18fec10 R11: ffff8880a18fe340 R12: 0000000000000000 R13: ffffffff87040c80 R14: ffffffff87040cc0 R15: dffffc0000000000 FS: 0000000000000000(0000) GS:ffff8880aec00000(0000) knlGS:0000000000000000 CS: 0010 DS: 0000 ES: 0000 CR0: 0000000080050033 CR2: 000000c438ca6000 CR3: 00000000a1b35000 CR4: 00000000001406f0 DR0: 0000000000000000 DR1: 0000000000000000 DR2: 0000000000000000 DR3: 0000000000000000 DR6: 00000000fffe0ff0 DR7: 0000000000000400 Call Trace: debug_smp_processor_id+0x1c/0x20 lib/smp_processor_id.c:57 rcu_dynticks_curr_cpu_in_eqs kernel/rcu/tree.c:360 [inline] rcu_is_watching+0x15/0xb0 kernel/rcu/tree.c:1130 rcu_read_unlock include/linux/rcupdate.h:681 [inline] batadv_nc_purge_orig_hash net/batman-adv/network-coding.c:420 [inline] batadv_nc_worker+0x40a/0x6d0 net/batman-adv/network-coding.c:726 process_one_work+0x863/0x1600 kernel/workqueue.c:2114 worker_thread+0x5d9/0x1050 kernel/workqueue.c:2248 kthread+0x319/0x430 kernel/kthread.c:232 ret_from_fork+0x24/0x30 arch/x86/entry/entry_64.S:404 Code: 00 00 00 e9 14 ec ff ff 65 48 8b 04 25 40 ee 01 00 48 85 c0 74 1a 65 8b 15 8b 9e a4 7e 81 e2 00 01 1f 00 75 0b 8b 90 50 13 00 00 <83> fa 01 74 01 c3 55 48 89 e5 48 8b 75 08 48 8b 88 58 13 00 00