INFO: task syz-executor.3:29065 blocked for more than 140 seconds. Not tainted 4.14.232-syzkaller #0 "echo 0 > /proc/sys/kernel/hung_task_timeout_secs" disables this message. syz-executor.3 D28968 29065 16313 0x00000004 Call Trace: context_switch kernel/sched/core.c:2808 [inline] __schedule+0x88b/0x1de0 kernel/sched/core.c:3384 schedule+0x8d/0x1b0 kernel/sched/core.c:3428 schedule_timeout+0x80a/0xe90 kernel/time/timer.c:1724 do_wait_for_common kernel/sched/completion.c:91 [inline] __wait_for_common kernel/sched/completion.c:112 [inline] wait_for_common+0x272/0x430 kernel/sched/completion.c:123 flush_work+0x3fe/0x770 kernel/workqueue.c:2893 __cancel_work_timer+0x321/0x460 kernel/workqueue.c:2964 p9_conn_destroy net/9p/trans_fd.c:899 [inline] p9_fd_close+0x299/0x420 net/9p/trans_fd.c:925 p9_client_create+0x736/0x12c0 net/9p/client.c:1095 v9fs_session_init+0x1c5/0x1540 fs/9p/v9fs.c:422 v9fs_mount+0x73/0x860 fs/9p/vfs_super.c:135 mount_fs+0x92/0x2a0 fs/super.c:1237 vfs_kern_mount.part.0+0x5b/0x470 fs/namespace.c:1046 vfs_kern_mount fs/namespace.c:1036 [inline] do_new_mount fs/namespace.c:2549 [inline] do_mount+0xe53/0x2a00 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+0x46/0xbb RIP: 0033:0x4665d9 RSP: 002b:00007fa8dfe93188 EFLAGS: 00000246 ORIG_RAX: 00000000000000a5 RAX: ffffffffffffffda RBX: 000000000056c200 RCX: 00000000004665d9 RDX: 00000000200001c0 RSI: 0000000020000180 RDI: 0000000000000000 RBP: 00000000004bfcb9 R08: 00000000200003c0 R09: 0000000000000000 R10: 0000000000000000 R11: 0000000000000246 R12: 000000000056c200 R13: 00007ffe3bc1a5ef R14: 00007fa8dfe93300 R15: 0000000000022000 Showing all locks held in the system: 1 lock held by khungtaskd/1530: #0: (tasklist_lock){.+.+}, at: [] debug_show_all_locks+0x7c/0x21a kernel/locking/lockdep.c:4548 2 locks held by kworker/0:3/8017: #0: ("events"){+.+.}, at: [] process_one_work+0x6b0/0x14a0 kernel/workqueue.c:2087 #1: ((&m->wq)){+.+.}, at: [] process_one_work+0x6e6/0x14a0 kernel/workqueue.c:2091 ============================================= NMI backtrace for cpu 0 CPU: 0 PID: 1530 Comm: khungtaskd Not tainted 4.14.232-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+0x1b2/0x281 lib/dump_stack.c:58 nmi_cpu_backtrace.cold+0x57/0x93 lib/nmi_backtrace.c:101 nmi_trigger_cpumask_backtrace+0x13a/0x180 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+0x5b9/0xb40 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: 4611 Comm: systemd-journal Not tainted 4.14.232-syzkaller #0 Hardware name: Google Google Compute Engine/Google Compute Engine, BIOS Google 01/01/2011 task: ffff8880a1f6a500 task.stack: ffff8880a1f70000 RIP: 0033:0x7fdef15f5820 RSP: 002b:00007ffec0434428 EFLAGS: 00000286 RAX: ffffffffffffffff RBX: 00007ffec0434730 RCX: fffffffffffffe00 RDX: 00000000000001a0 RSI: 0000000000080042 RDI: 0000556f6a096310 RBP: 000000000000000d R08: 0000000000000000 R09: 00000000ffffffff R10: 0000000000000069 R11: 0000000000000246 R12: 00000000ffffffff R13: 0000556f6a08f040 R14: 00007ffec04346f0 R15: 0000556f6a094270 FS: 00007fdef20648c0(0000) GS:ffff8880ba500000(0000) knlGS:0000000000000000 CS: 0010 DS: 0000 ES: 0000 CR0: 0000000080050033 CR2: 00007fdeef4d0000 CR3: 00000000a18a6000 CR4: 00000000001406e0 DR0: 0000000000000000 DR1: 0000000000000000 DR2: 0000000000000000 DR3: 0000000000000000 DR6: 00000000fffe0ff0 DR7: 0000000000000400