INFO: task syz-executor.0:8759 can't die for more than 143 seconds. syz-executor.0 D28184 8759 8721 0x00004004 Call Trace: context_switch kernel/sched/core.c:3384 [inline] __schedule+0x94f/0x1e70 kernel/sched/core.c:4069 schedule+0xd9/0x260 kernel/sched/core.c:4136 schedule_timeout+0x717/0xc50 kernel/time/timer.c:1871 do_wait_for_common kernel/sched/completion.c:83 [inline] __wait_for_common kernel/sched/completion.c:104 [inline] wait_for_common kernel/sched/completion.c:115 [inline] wait_for_completion+0x29c/0x440 kernel/sched/completion.c:136 __flush_work+0x508/0xa60 kernel/workqueue.c:3040 __cancel_work_timer+0x3d9/0x540 kernel/workqueue.c:3127 cancel_work_sync+0x18/0x20 kernel/workqueue.c:3163 p9_conn_destroy net/9p/trans_fd.c:868 [inline] p9_fd_close+0x329/0x570 net/9p/trans_fd.c:898 p9_client_create+0x98c/0x1430 net/9p/client.c:1069 v9fs_session_init+0x1e7/0x18c0 fs/9p/v9fs.c:406 v9fs_mount+0x7d/0x990 fs/9p/vfs_super.c:124 legacy_get_tree+0x108/0x220 fs/fs_context.c:647 vfs_get_tree+0x8e/0x300 fs/super.c:1542 do_new_mount fs/namespace.c:2823 [inline] do_mount+0x143d/0x1d10 fs/namespace.c:3143 ksys_mount+0xdb/0x150 fs/namespace.c:3352 __do_sys_mount fs/namespace.c:3366 [inline] __se_sys_mount fs/namespace.c:3363 [inline] __x64_sys_mount+0xbe/0x150 fs/namespace.c:3363 do_syscall_64+0xfa/0x760 arch/x86/entry/common.c:290 entry_SYSCALL_64_after_hwframe+0x49/0xbe RIP: 0033:0x459a29 Code: fa ff 48 8b 44 24 10 48 8b 4c 24 30 48 8d 91 d0 10 00 00 48 89 14 24 48 89 44 24 08 48 c7 44 24 10 02 00 00 00 e8 57 d8 fa ff <48> 8b 44 24 18 48 8b 4c 24 30 48 81 c1 d8 10 00 00 48 89 0c 24 48 RSP: 002b:00007f387f5eec78 EFLAGS: 00000246 ORIG_RAX: 00000000000000a5 RAX: ffffffffffffffda RBX: 0000000000000005 RCX: 0000000000459a29 RDX: 0000000020000140 RSI: 0000000020000000 RDI: 0000000000000000 RBP: 000000000075c118 R08: 00000000200005c0 R09: 0000000000000000 R10: 0000000000000000 R11: 0000000000000246 R12: 00007f387f5ef6d4 R13: 00000000004c61d2 R14: 00000000004db1e8 R15: 00000000ffffffff INFO: task syz-executor.0:8759 blocked for more than 143 seconds. Not tainted 5.4.0-rc1-next-20191003 #0 "echo 0 > /proc/sys/kernel/hung_task_timeout_secs" disables this message. syz-executor.0 D28184 8759 8721 0x00004004 Call Trace: context_switch kernel/sched/core.c:3384 [inline] __schedule+0x94f/0x1e70 kernel/sched/core.c:4069 schedule+0xd9/0x260 kernel/sched/core.c:4136 schedule_timeout+0x717/0xc50 kernel/time/timer.c:1871 do_wait_for_common kernel/sched/completion.c:83 [inline] __wait_for_common kernel/sched/completion.c:104 [inline] wait_for_common kernel/sched/completion.c:115 [inline] wait_for_completion+0x29c/0x440 kernel/sched/completion.c:136 __flush_work+0x508/0xa60 kernel/workqueue.c:3040 __cancel_work_timer+0x3d9/0x540 kernel/workqueue.c:3127 cancel_work_sync+0x18/0x20 kernel/workqueue.c:3163 p9_conn_destroy net/9p/trans_fd.c:868 [inline] p9_fd_close+0x329/0x570 net/9p/trans_fd.c:898 p9_client_create+0x98c/0x1430 net/9p/client.c:1069 v9fs_session_init+0x1e7/0x18c0 fs/9p/v9fs.c:406 v9fs_mount+0x7d/0x990 fs/9p/vfs_super.c:124 legacy_get_tree+0x108/0x220 fs/fs_context.c:647 vfs_get_tree+0x8e/0x300 fs/super.c:1542 do_new_mount fs/namespace.c:2823 [inline] do_mount+0x143d/0x1d10 fs/namespace.c:3143 ksys_mount+0xdb/0x150 fs/namespace.c:3352 __do_sys_mount fs/namespace.c:3366 [inline] __se_sys_mount fs/namespace.c:3363 [inline] __x64_sys_mount+0xbe/0x150 fs/namespace.c:3363 do_syscall_64+0xfa/0x760 arch/x86/entry/common.c:290 entry_SYSCALL_64_after_hwframe+0x49/0xbe RIP: 0033:0x459a29 Code: fa ff 48 8b 44 24 10 48 8b 4c 24 30 48 8d 91 d0 10 00 00 48 89 14 24 48 89 44 24 08 48 c7 44 24 10 02 00 00 00 e8 57 d8 fa ff <48> 8b 44 24 18 48 8b 4c 24 30 48 81 c1 d8 10 00 00 48 89 0c 24 48 RSP: 002b:00007f387f5eec78 EFLAGS: 00000246 ORIG_RAX: 00000000000000a5 RAX: ffffffffffffffda RBX: 0000000000000005 RCX: 0000000000459a29 RDX: 0000000020000140 RSI: 0000000020000000 RDI: 0000000000000000 RBP: 000000000075c118 R08: 00000000200005c0 R09: 0000000000000000 R10: 0000000000000000 R11: 0000000000000246 R12: 00007f387f5ef6d4 R13: 00000000004c61d2 R14: 00000000004db1e8 R15: 00000000ffffffff Showing all locks held in the system: 1 lock held by khungtaskd/1056: #0: ffffffff88faae00 (rcu_read_lock){....}, at: debug_show_all_locks+0x5f/0x27e kernel/locking/lockdep.c:5337 1 lock held by rsyslogd/8590: 2 locks held by getty/8680: #0: ffff8880a7960090 (&tty->ldisc_sem){++++}, at: ldsem_down_read+0x33/0x40 drivers/tty/tty_ldsem.c:340 #1: ffffc90005f152e0 (&ldata->atomic_read_lock){+.+.}, at: n_tty_read+0x232/0x1c10 drivers/tty/n_tty.c:2156 2 locks held by getty/8681: #0: ffff88809bdaf090 (&tty->ldisc_sem){++++}, at: ldsem_down_read+0x33/0x40 drivers/tty/tty_ldsem.c:340 #1: ffffc90005f352e0 (&ldata->atomic_read_lock){+.+.}, at: n_tty_read+0x232/0x1c10 drivers/tty/n_tty.c:2156 2 locks held by getty/8682: #0: ffff8880a3b8a090 (&tty->ldisc_sem){++++}, at: ldsem_down_read+0x33/0x40 drivers/tty/tty_ldsem.c:340 #1: ffffc90005f192e0 (&ldata->atomic_read_lock){+.+.}, at: n_tty_read+0x232/0x1c10 drivers/tty/n_tty.c:2156 2 locks held by getty/8683: #0: ffff888096b14090 (&tty->ldisc_sem){++++}, at: ldsem_down_read+0x33/0x40 drivers/tty/tty_ldsem.c:340 #1: ffffc90005f392e0 (&ldata->atomic_read_lock){+.+.}, at: n_tty_read+0x232/0x1c10 drivers/tty/n_tty.c:2156 2 locks held by getty/8684: #0: ffff888095bde090 (&tty->ldisc_sem){++++}, at: ldsem_down_read+0x33/0x40 drivers/tty/tty_ldsem.c:340 #1: ffffc90005f312e0 (&ldata->atomic_read_lock){+.+.}, at: n_tty_read+0x232/0x1c10 drivers/tty/n_tty.c:2156 2 locks held by getty/8685: #0: ffff8880a1885090 (&tty->ldisc_sem){++++}, at: ldsem_down_read+0x33/0x40 drivers/tty/tty_ldsem.c:340 #1: ffffc90005f252e0 (&ldata->atomic_read_lock){+.+.}, at: n_tty_read+0x232/0x1c10 drivers/tty/n_tty.c:2156 2 locks held by getty/8686: #0: ffff88808be72090 (&tty->ldisc_sem){++++}, at: ldsem_down_read+0x33/0x40 drivers/tty/tty_ldsem.c:340 #1: ffffc90005f092e0 (&ldata->atomic_read_lock){+.+.}, at: n_tty_read+0x232/0x1c10 drivers/tty/n_tty.c:2156 2 locks held by kworker/1:2/8724: #0: ffff8880aa427d28 ((wq_completion)events){+.+.}, at: __write_once_size include/linux/compiler.h:226 [inline] #0: ffff8880aa427d28 ((wq_completion)events){+.+.}, at: arch_atomic64_set arch/x86/include/asm/atomic64_64.h:34 [inline] #0: ffff8880aa427d28 ((wq_completion)events){+.+.}, at: atomic64_set include/asm-generic/atomic-instrumented.h:855 [inline] #0: ffff8880aa427d28 ((wq_completion)events){+.+.}, at: atomic_long_set include/asm-generic/atomic-long.h:40 [inline] #0: ffff8880aa427d28 ((wq_completion)events){+.+.}, at: set_work_data kernel/workqueue.c:620 [inline] #0: ffff8880aa427d28 ((wq_completion)events){+.+.}, at: set_work_pool_and_clear_pending kernel/workqueue.c:647 [inline] #0: ffff8880aa427d28 ((wq_completion)events){+.+.}, at: process_one_work+0x88b/0x1740 kernel/workqueue.c:2240 #1: ffff888091e47dc0 ((work_completion)(&m->wq)){+.+.}, at: process_one_work+0x8c1/0x1740 kernel/workqueue.c:2244 ============================================= NMI backtrace for cpu 1 CPU: 1 PID: 1056 Comm: khungtaskd Not tainted 5.4.0-rc1-next-20191003 #0 Hardware name: Google Google Compute Engine/Google Compute Engine, BIOS Google 01/01/2011 Call Trace: __dump_stack lib/dump_stack.c:77 [inline] dump_stack+0x172/0x1f0 lib/dump_stack.c:113 nmi_cpu_backtrace.cold+0x70/0xb2 lib/nmi_backtrace.c:101 nmi_trigger_cpumask_backtrace+0x23b/0x28b 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:146 [inline] check_hung_uninterruptible_tasks kernel/hung_task.c:269 [inline] watchdog+0xc99/0x1360 kernel/hung_task.c:353 kthread+0x361/0x430 kernel/kthread.c:255 ret_from_fork+0x24/0x30 arch/x86/entry/entry_64.S:352 Sending NMI from CPU 1 to CPUs 0: NMI backtrace for cpu 0 skipped: idling at native_safe_halt+0xe/0x10 arch/x86/include/asm/irqflags.h:60