INFO: task syz-executor.4:17465 can't die for more than 143 seconds. syz-executor.4 D26624 17465 9834 0x00004004 Call Trace: context_switch kernel/sched/core.c:3380 [inline] __schedule+0x934/0x1f90 kernel/sched/core.c:4080 schedule+0xdc/0x2b0 kernel/sched/core.c:4154 schedule_timeout+0x58d/0x8c0 kernel/time/timer.c:1874 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_workqueue+0x40a/0x14c0 kernel/workqueue.c:2829 nbd_start_device_ioctl drivers/block/nbd.c:1311 [inline] __nbd_ioctl drivers/block/nbd.c:1386 [inline] nbd_ioctl+0x817/0xc4b drivers/block/nbd.c:1426 __blkdev_driver_ioctl block/ioctl.c:321 [inline] blkdev_ioctl+0x263/0x670 block/ioctl.c:717 block_ioctl+0xee/0x130 fs/block_dev.c:1983 vfs_ioctl fs/ioctl.c:47 [inline] ksys_ioctl+0x123/0x180 fs/ioctl.c:763 __do_sys_ioctl fs/ioctl.c:772 [inline] __se_sys_ioctl fs/ioctl.c:770 [inline] __x64_sys_ioctl+0x73/0xb0 fs/ioctl.c:770 do_syscall_64+0xfa/0x790 arch/x86/entry/common.c:295 entry_SYSCALL_64_after_hwframe+0x49/0xbe RIP: 0033:0x45c479 Code: Bad RIP value. RSP: 002b:00007ff1233d7c78 EFLAGS: 00000246 ORIG_RAX: 0000000000000010 RAX: ffffffffffffffda RBX: 00007ff1233d86d4 RCX: 000000000045c479 RDX: 0000000000000000 RSI: 000000000000ab03 RDI: 0000000000000004 RBP: 000000000076bf20 R08: 0000000000000000 R09: 0000000000000000 R10: 0000000000000000 R11: 0000000000000246 R12: 00000000ffffffff R13: 0000000000000402 R14: 00000000004c65f9 R15: 000000000076bf2c INFO: task syz-executor.4:17465 blocked for more than 143 seconds. Not tainted 5.6.0-rc3-next-20200225-syzkaller #0 "echo 0 > /proc/sys/kernel/hung_task_timeout_secs" disables this message. syz-executor.4 D26624 17465 9834 0x00004004 Call Trace: context_switch kernel/sched/core.c:3380 [inline] __schedule+0x934/0x1f90 kernel/sched/core.c:4080 schedule+0xdc/0x2b0 kernel/sched/core.c:4154 schedule_timeout+0x58d/0x8c0 kernel/time/timer.c:1874 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_workqueue+0x40a/0x14c0 kernel/workqueue.c:2829 nbd_start_device_ioctl drivers/block/nbd.c:1311 [inline] __nbd_ioctl drivers/block/nbd.c:1386 [inline] nbd_ioctl+0x817/0xc4b drivers/block/nbd.c:1426 __blkdev_driver_ioctl block/ioctl.c:321 [inline] blkdev_ioctl+0x263/0x670 block/ioctl.c:717 block_ioctl+0xee/0x130 fs/block_dev.c:1983 vfs_ioctl fs/ioctl.c:47 [inline] ksys_ioctl+0x123/0x180 fs/ioctl.c:763 __do_sys_ioctl fs/ioctl.c:772 [inline] __se_sys_ioctl fs/ioctl.c:770 [inline] __x64_sys_ioctl+0x73/0xb0 fs/ioctl.c:770 do_syscall_64+0xfa/0x790 arch/x86/entry/common.c:295 entry_SYSCALL_64_after_hwframe+0x49/0xbe RIP: 0033:0x45c479 Code: Bad RIP value. RSP: 002b:00007ff1233d7c78 EFLAGS: 00000246 ORIG_RAX: 0000000000000010 RAX: ffffffffffffffda RBX: 00007ff1233d86d4 RCX: 000000000045c479 RDX: 0000000000000000 RSI: 000000000000ab03 RDI: 0000000000000004 RBP: 000000000076bf20 R08: 0000000000000000 R09: 0000000000000000 R10: 0000000000000000 R11: 0000000000000246 R12: 00000000ffffffff R13: 0000000000000402 R14: 00000000004c65f9 R15: 000000000076bf2c Showing all locks held in the system: 1 lock held by khungtaskd/1124: #0: ffffffff89badac0 (rcu_read_lock){....}, at: debug_show_all_locks+0x5f/0x279 kernel/locking/lockdep.c:5546 2 locks held by rs:main Q:Reg/9682: #0: ffff88809f8f9660 (&f->f_pos_lock){+.+.}, at: __fdget_pos+0xee/0x110 fs/file.c:821 #1: ffff8880996d0418 (sb_writers#3){.+.+}, at: file_start_write include/linux/fs.h:2903 [inline] #1: ffff8880996d0418 (sb_writers#3){.+.+}, at: vfs_write+0x485/0x5d0 fs/read_write.c:557 1 lock held by rsyslogd/9684: #0: ffff88809338a8a0 (&f->f_pos_lock){+.+.}, at: __fdget_pos+0xee/0x110 fs/file.c:821 2 locks held by getty/9774: #0: ffff888094178090 (&tty->ldisc_sem){++++}, at: ldsem_down_read+0x33/0x40 drivers/tty/tty_ldsem.c:340 #1: ffffc900018ab2e0 (&ldata->atomic_read_lock){+.+.}, at: n_tty_read+0x220/0x1bf0 drivers/tty/n_tty.c:2156 2 locks held by getty/9775: #0: ffff888097738090 (&tty->ldisc_sem){++++}, at: ldsem_down_read+0x33/0x40 drivers/tty/tty_ldsem.c:340 #1: ffffc900019632e0 (&ldata->atomic_read_lock){+.+.}, at: n_tty_read+0x220/0x1bf0 drivers/tty/n_tty.c:2156 2 locks held by getty/9776: #0: ffff8880a72fe090 (&tty->ldisc_sem){++++}, at: ldsem_down_read+0x33/0x40 drivers/tty/tty_ldsem.c:340 #1: ffffc900019832e0 (&ldata->atomic_read_lock){+.+.}, at: n_tty_read+0x220/0x1bf0 drivers/tty/n_tty.c:2156 2 locks held by getty/9777: #0: ffff888093ef1090 (&tty->ldisc_sem){++++}, at: ldsem_down_read+0x33/0x40 drivers/tty/tty_ldsem.c:340 #1: ffffc900018bb2e0 (&ldata->atomic_read_lock){+.+.}, at: n_tty_read+0x220/0x1bf0 drivers/tty/n_tty.c:2156 2 locks held by getty/9778: #0: ffff88809fc59090 (&tty->ldisc_sem){++++}, at: ldsem_down_read+0x33/0x40 drivers/tty/tty_ldsem.c:340 #1: ffffc9000188b2e0 (&ldata->atomic_read_lock){+.+.}, at: n_tty_read+0x220/0x1bf0 drivers/tty/n_tty.c:2156 2 locks held by getty/9779: #0: ffff88809fc0d090 (&tty->ldisc_sem){++++}, at: ldsem_down_read+0x33/0x40 drivers/tty/tty_ldsem.c:340 #1: ffffc900019732e0 (&ldata->atomic_read_lock){+.+.}, at: n_tty_read+0x220/0x1bf0 drivers/tty/n_tty.c:2156 2 locks held by getty/9780: #0: ffff8880a0105090 (&tty->ldisc_sem){++++}, at: ldsem_down_read+0x33/0x40 drivers/tty/tty_ldsem.c:340 #1: ffffc9000185b2e0 (&ldata->atomic_read_lock){+.+.}, at: n_tty_read+0x220/0x1bf0 drivers/tty/n_tty.c:2156 2 locks held by kworker/u5:1/10625: #0: ffff88808fed6128 ((wq_completion)knbd0-recv){+.+.}, at: __write_once_size include/linux/compiler.h:250 [inline] #0: ffff88808fed6128 ((wq_completion)knbd0-recv){+.+.}, at: arch_atomic64_set arch/x86/include/asm/atomic64_64.h:34 [inline] #0: ffff88808fed6128 ((wq_completion)knbd0-recv){+.+.}, at: atomic64_set include/asm-generic/atomic-instrumented.h:856 [inline] #0: ffff88808fed6128 ((wq_completion)knbd0-recv){+.+.}, at: atomic_long_set include/asm-generic/atomic-long.h:41 [inline] #0: ffff88808fed6128 ((wq_completion)knbd0-recv){+.+.}, at: set_work_data kernel/workqueue.c:615 [inline] #0: ffff88808fed6128 ((wq_completion)knbd0-recv){+.+.}, at: set_work_pool_and_clear_pending kernel/workqueue.c:642 [inline] #0: ffff88808fed6128 ((wq_completion)knbd0-recv){+.+.}, at: process_one_work+0x8dd/0x17a0 kernel/workqueue.c:2237 #1: ffffc90001c57dc0 ((work_completion)(&args->work)){+.+.}, at: process_one_work+0x917/0x17a0 kernel/workqueue.c:2241 4 locks held by kworker/u4:12/17399: ============================================= NMI backtrace for cpu 1 CPU: 1 PID: 1124 Comm: khungtaskd Not tainted 5.6.0-rc3-next-20200225-syzkaller #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+0x197/0x210 lib/dump_stack.c:118 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:147 [inline] check_hung_uninterruptible_tasks kernel/hung_task.c:249 [inline] watchdog+0xdf1/0x14e0 kernel/hung_task.c:333 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 CPU: 0 PID: 17399 Comm: kworker/u4:12 Not tainted 5.6.0-rc3-next-20200225-syzkaller #0 Hardware name: Google Google Compute Engine/Google Compute Engine, BIOS Google 01/01/2011 Workqueue: krdsd rds_connect_worker RIP: 0010:strlen+0x67/0xa0 lib/string.c:547 Code: 00 00 fc ff df 4c 89 e0 48 83 c0 01 48 89 c2 48 89 c1 48 c1 ea 03 83 e1 07 0f b6 14 1a 38 ca 7f 04 84 d2 75 23 80 38 00 75 de <48> 83 c4 08 4c 29 e0 5b 41 5c 5d c3 48 83 c4 08 31 c0 5b 41 5c 5d RSP: 0018:ffffc900028577f8 EFLAGS: 00000046 RAX: ffffffff8902f8a5 RBX: dffffc0000000000 RCX: 0000000000000005 RDX: 0000000000000006 RSI: ffffc90005bb8018 RDI: ffffffff8902f880 RBP: ffffc90002857810 R08: 1ffffffff154c0f8 R09: fffffbfff154c0f9 R10: fffffbfff154c0f8 R11: ffffffff8aa607c7 R12: ffffffff8902f880 R13: ffffffff86b0ab4a R14: ffffffff89b94de0 R15: ffffc900028578d0 FS: 0000000000000000(0000) GS:ffff8880ae800000(0000) knlGS:0000000000000000 CS: 0010 DS: 0000 ES: 0000 CR0: 0000000080050033 CR2: 000000c0199ca000 CR3: 0000000094100000 CR4: 00000000001406f0 DR0: 0000000000000000 DR1: 0000000000000000 DR2: 0000000000000000 DR3: 0000000000000000 DR6: 00000000fffe0ff0 DR7: 0000000000000400 Call Trace: trace_event_get_offsets_lock_acquire include/trace/events/lock.h:13 [inline] perf_trace_lock+0xb1/0x4c0 include/trace/events/lock.h:39 trace_lock_release include/trace/events/lock.h:58 [inline] lock_release+0x5a8/0x960 kernel/locking/lockdep.c:4737 __raw_spin_unlock_bh include/linux/spinlock_api_smp.h:174 [inline] _raw_spin_unlock_bh+0x16/0x30 kernel/locking/spinlock.c:207 spin_unlock_bh include/linux/spinlock.h:383 [inline] inet_csk_find_open_port net/ipv4/inet_connection_sock.c:229 [inline] inet_csk_get_port+0xd5a/0x24b0 net/ipv4/inet_connection_sock.c:300 __inet_bind+0x5bf/0xbf0 net/ipv4/af_inet.c:524 inet_bind+0xfa/0x160 net/ipv4/af_inet.c:453 rds_tcp_conn_path_connect+0x536/0x880 net/rds/tcp_connect.c:144 rds_connect_worker+0x1b6/0x2d0 net/rds/threads.c:176 process_one_work+0xa05/0x17a0 kernel/workqueue.c:2266 worker_thread+0x98/0xe40 kernel/workqueue.c:2412 kthread+0x361/0x430 kernel/kthread.c:255 ret_from_fork+0x24/0x30 arch/x86/entry/entry_64.S:352