INFO: task syz-executor.5:31474 blocked for more than 140 seconds. Not tainted 4.14.175-syzkaller #0 "echo 0 > /proc/sys/kernel/hung_task_timeout_secs" disables this message. syz-executor.5 D27728 31474 6352 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 flush_work+0x3f5/0x780 kernel/workqueue.c:2893 __cancel_work_timer+0x2d0/0x460 kernel/workqueue.c:2964 p9_conn_destroy net/9p/trans_fd.c:872 [inline] p9_fd_close+0x28d/0x420 net/9p/trans_fd.c:899 p9_client_create+0x787/0x10f0 net/9p/client.c:1095 v9fs_session_init+0x1dc/0x1620 fs/9p/v9fs.c:422 v9fs_mount+0x79/0x850 fs/9p/vfs_super.c:135 mount_fs+0x92/0x2a0 fs/super.c:1237 vfs_kern_mount.part.0+0x5b/0x3c0 fs/namespace.c:1046 vfs_kern_mount fs/namespace.c:1036 [inline] do_new_mount fs/namespace.c:2549 [inline] do_mount+0x3c9/0x24f0 fs/namespace.c:2879 SYSC_mount fs/namespace.c:3095 [inline] SyS_mount+0xa8/0x120 fs/namespace.c:3072 do_syscall_64+0x1d5/0x640 arch/x86/entry/common.c:292 entry_SYSCALL_64_after_hwframe+0x42/0xb7 RIP: 0033:0x45c889 RSP: 002b:00007fa3c440fc78 EFLAGS: 00000246 ORIG_RAX: 00000000000000a5 RAX: ffffffffffffffda RBX: 00007fa3c44106d4 RCX: 000000000045c889 RDX: 0000000020000100 RSI: 0000000020000000 RDI: 0000000000000000 RBP: 000000000076bfa0 R08: 0000000020000200 R09: 0000000000000000 R10: 0000000000000440 R11: 0000000000000246 R12: 00000000ffffffff R13: 000000000000074a R14: 00000000004ca0c5 R15: 000000000076bfac Showing all locks held in the system: 1 lock held by khungtaskd/1056: #0: (tasklist_lock){.+.+}, at: [] debug_show_all_locks+0x7c/0x21a kernel/locking/lockdep.c:4544 1 lock held by in:imklog/6024: #0: (&f->f_pos_lock){+.+.}, at: [] __fdget_pos+0xa6/0xc0 fs/file.c:769 2 locks held by kworker/0:2/21888: #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+0x727/0x1540 kernel/workqueue.c:2087 #1: ((&m->rq)){+.+.}, at: [] process_one_work+0x761/0x1540 kernel/workqueue.c:2091 ============================================= NMI backtrace for cpu 0 CPU: 0 PID: 1056 Comm: khungtaskd Not tainted 4.14.175-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: 8 Comm: rcu_preempt Not tainted 4.14.175-syzkaller #0 Hardware name: Google Google Compute Engine/Google Compute Engine, BIOS Google 01/01/2011 task: ffff8880a9852200 task.stack: ffff8880a9860000 RIP: 0010:schedule_timeout+0x43f/0xe40 kernel/time/timer.c:1747 RSP: 0018:ffff8880a9867c50 EFLAGS: 00000246 RAX: 0000000080000000 RBX: 000000010001ba2e RCX: 0000000000000000 RDX: 0000000000000004 RSI: 0000000000000001 RDI: ffff8880a9867cd0 RBP: ffff8880a9867d68 R08: 0000000000000001 R09: 0000000000000000 R10: 0000000000000000 R11: 0000000000000000 R12: 1ffff1101530cf90 R13: ffff8880aeb239c0 R14: ffff8880aeb239c0 R15: ffff8880a9867cd0 FS: 0000000000000000(0000) GS:ffff8880aeb00000(0000) knlGS:0000000000000000 CS: 0010 DS: 0000 ES: 0000 CR0: 0000000080050033 CR2: 00007f1aa5442008 CR3: 0000000094e17000 CR4: 00000000001406e0 DR0: 0000000000000000 DR1: 0000000000000000 DR2: 0000000000000000 DR3: 0000000000000000 DR6: 00000000fffe0ff0 DR7: 0000000000000400 Call Trace: rcu_gp_kthread+0xb8e/0x1ce0 kernel/rcu/tree.c:2255 kthread+0x30d/0x420 kernel/kthread.c:232 ret_from_fork+0x24/0x30 arch/x86/entry/entry_64.S:404 Code: 00 48 8d 70 a0 e8 52 e2 0c fb e8 7d d6 19 fb 48 8b 74 24 60 48 8b 7c 24 28 e8 8e 38 00 00 e8 69 d6 19 fb e8 34 1c ff ff 4c 89 ff 8c e4 0c fb 48 c7 c6 20 ee d8 87 4c 89 ff e8 3d e9 bd fc 48