INFO: task syz-executor.4:14936 blocked for more than 143 seconds. Not tainted 5.4.0-rc2+ #0 "echo 0 > /proc/sys/kernel/hung_task_timeout_secs" disables this message. syz-executor.4 D28160 14936 11596 0x00000004 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_preempt_disabled+0x13/0x20 kernel/sched/core.c:4195 __mutex_lock_common kernel/locking/mutex.c:1033 [inline] __mutex_lock+0x7b0/0x13c0 kernel/locking/mutex.c:1103 mutex_lock_nested+0x16/0x20 kernel/locking/mutex.c:1118 blkdev_put+0x34/0x560 fs/block_dev.c:1887 blkdev_close+0x8b/0xb0 fs/block_dev.c:1936 __fput+0x2ff/0x890 fs/file_table.c:280 ____fput+0x16/0x20 fs/file_table.c:313 task_work_run+0x145/0x1c0 kernel/task_work.c:113 tracehook_notify_resume include/linux/tracehook.h:188 [inline] exit_to_usermode_loop+0x316/0x380 arch/x86/entry/common.c:163 prepare_exit_to_usermode arch/x86/entry/common.c:194 [inline] syscall_return_slowpath arch/x86/entry/common.c:274 [inline] do_syscall_64+0x65f/0x760 arch/x86/entry/common.c:300 entry_SYSCALL_64_after_hwframe+0x49/0xbe RIP: 0033:0x413741 Code: 00 b8 2d f8 ff ff 0f 44 c2 c3 66 66 66 66 66 66 2e 0f 1f 84 00 00 00 00 00 31 c0 c3 66 66 66 66 2e 0f 1f 84 00 00 00 00 00 31 c3 66 66 66 66 2e 0f 1f 84 00 00 00 00 00 48 c7 07 40 37 41 00 RSP: 002b:00007ffea0d05930 EFLAGS: 00000293 ORIG_RAX: 0000000000000003 RAX: 0000000000000000 RBX: 0000000000000007 RCX: 0000000000413741 RDX: 0000000000000000 RSI: 0000000000001b66 RDI: 0000000000000006 RBP: 0000000000000001 R08: 000000003ccb9b66 R09: 000000003ccb9b6a R10: 00007ffea0d05a10 R11: 0000000000000293 R12: 000000000075c9a0 R13: 000000000075c9a0 R14: 0000000000761438 R15: 000000000075bfd4 INFO: task syz-executor.4:14937 blocked for more than 143 seconds. Not tainted 5.4.0-rc2+ #0 "echo 0 > /proc/sys/kernel/hung_task_timeout_secs" disables this message. syz-executor.4 D26152 14937 11596 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_workqueue+0x40f/0x14c0 kernel/workqueue.c:2826 nbd_start_device_ioctl drivers/block/nbd.c:1272 [inline] __nbd_ioctl drivers/block/nbd.c:1347 [inline] nbd_ioctl+0xb2e/0xc44 drivers/block/nbd.c:1387 __blkdev_driver_ioctl block/ioctl.c:304 [inline] blkdev_ioctl+0xedb/0x1c20 block/ioctl.c:606 block_ioctl+0xee/0x130 fs/block_dev.c:1954 vfs_ioctl fs/ioctl.c:46 [inline] file_ioctl fs/ioctl.c:509 [inline] do_vfs_ioctl+0xdb6/0x13e0 fs/ioctl.c:696 ksys_ioctl+0xab/0xd0 fs/ioctl.c:713 __do_sys_ioctl fs/ioctl.c:720 [inline] __se_sys_ioctl fs/ioctl.c:718 [inline] __x64_sys_ioctl+0x73/0xb0 fs/ioctl.c:718 do_syscall_64+0xfa/0x760 arch/x86/entry/common.c:290 entry_SYSCALL_64_after_hwframe+0x49/0xbe RIP: 0033:0x459a59 Code: Bad RIP value. RSP: 002b:00007f3166824c78 EFLAGS: 00000246 ORIG_RAX: 0000000000000010 RAX: ffffffffffffffda RBX: 0000000000000002 RCX: 0000000000459a59 RDX: 0000000000000000 RSI: 000000000000ab03 RDI: 0000000000000007 RBP: 000000000075bf20 R08: 0000000000000000 R09: 0000000000000000 R10: 0000000000000000 R11: 0000000000000246 R12: 00007f31668256d4 R13: 00000000004c3381 R14: 00000000004d6f90 R15: 00000000ffffffff INFO: task syz-executor.4:14940 blocked for more than 143 seconds. Not tainted 5.4.0-rc2+ #0 "echo 0 > /proc/sys/kernel/hung_task_timeout_secs" disables this message. syz-executor.4 D26280 14940 11596 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 io_schedule+0x1c/0x70 kernel/sched/core.c:5780 wait_on_page_bit_common mm/filemap.c:1174 [inline] wait_on_page_bit mm/filemap.c:1223 [inline] wait_on_page_locked include/linux/pagemap.h:527 [inline] wait_on_page_read mm/filemap.c:2767 [inline] do_read_cache_page+0xf2f/0x2140 mm/filemap.c:2810 read_cache_page+0x5e/0x70 mm/filemap.c:2894 read_mapping_page include/linux/pagemap.h:396 [inline] read_dev_sector+0x71/0x310 block/partition-generic.c:667 read_part_sector block/partitions/check.h:38 [inline] adfspart_check_ICS+0x12d/0xc90 block/partitions/acorn.c:361 check_partition+0x3bc/0x6ce block/partitions/check.c:167 rescan_partitions+0x230/0xa30 block/partition-generic.c:531 __blkdev_get+0x1213/0x1660 fs/block_dev.c:1637 blkdev_get+0x47/0x2c0 fs/block_dev.c:1707 blkdev_open+0x205/0x290 fs/block_dev.c:1846 do_dentry_open+0x4df/0x1250 fs/open.c:797 vfs_open+0xa0/0xd0 fs/open.c:914 do_last fs/namei.c:3408 [inline] path_openat+0x10e9/0x46d0 fs/namei.c:3525 do_filp_open+0x1a1/0x280 fs/namei.c:3555 do_sys_open+0x3fe/0x5d0 fs/open.c:1097 __do_sys_open fs/open.c:1115 [inline] __se_sys_open fs/open.c:1110 [inline] __x64_sys_open+0x7e/0xc0 fs/open.c:1110 do_syscall_64+0xfa/0x760 arch/x86/entry/common.c:290 entry_SYSCALL_64_after_hwframe+0x49/0xbe RIP: 0033:0x413941 Code: 31 c0 bf 89 3c 44 00 e8 0d d7 00 00 66 83 bb c8 00 00 00 ff 74 0b 31 c0 5b c3 0f 1f 80 00 00 00 00 31 c0 bf 73 36 44 00 e8 ec 00 00 31 c0 5b c3 0f 1f 84 00 00 00 00 00 53 48 89 fb 0f bf bf RSP: 002b:00007f31668037a0 EFLAGS: 00000293 ORIG_RAX: 0000000000000002 RAX: ffffffffffffffda RBX: 6666666666666667 RCX: 0000000000413941 RDX: 0000000000000000 RSI: 0000000000000000 RDI: 00007f3166803850 RBP: 000000000075bfc8 R08: 00007f31668037b0 R09: 000000000075bfc8 R10: 0000000000000000 R11: 0000000000000293 R12: 00007f31668046d4 R13: 00000000004c9074 R14: 00000000004e0530 R15: 00000000ffffffff Showing all locks held in the system: 1 lock held by khungtaskd/1063: #0: ffffffff88faae00 (rcu_read_lock){....}, at: debug_show_all_locks+0x5f/0x27e kernel/locking/lockdep.c:5337 2 locks held by getty/9053: #0: ffff888098e28090 (&tty->ldisc_sem){++++}, at: ldsem_down_read+0x33/0x40 drivers/tty/tty_ldsem.c:340 #1: ffffc90005f5d2e0 (&ldata->atomic_read_lock){+.+.}, at: n_tty_read+0x232/0x1c10 drivers/tty/n_tty.c:2156 2 locks held by getty/9054: #0: ffff8880a12ff090 (&tty->ldisc_sem){++++}, at: ldsem_down_read+0x33/0x40 drivers/tty/tty_ldsem.c:340 #1: ffffc90005f552e0 (&ldata->atomic_read_lock){+.+.}, at: n_tty_read+0x232/0x1c10 drivers/tty/n_tty.c:2156 2 locks held by getty/9055: #0: ffff8880a0d3c090 (&tty->ldisc_sem){++++}, at: ldsem_down_read+0x33/0x40 drivers/tty/tty_ldsem.c:340 #1: ffffc90005f412e0 (&ldata->atomic_read_lock){+.+.}, at: n_tty_read+0x232/0x1c10 drivers/tty/n_tty.c:2156 2 locks held by getty/9056: #0: ffff888098e4d090 (&tty->ldisc_sem){++++}, at: ldsem_down_read+0x33/0x40 drivers/tty/tty_ldsem.c:340 #1: ffffc90005f592e0 (&ldata->atomic_read_lock){+.+.}, at: n_tty_read+0x232/0x1c10 drivers/tty/n_tty.c:2156 2 locks held by getty/9057: #0: ffff88809bcaf090 (&tty->ldisc_sem){++++}, at: ldsem_down_read+0x33/0x40 drivers/tty/tty_ldsem.c:340 #1: ffffc90005f452e0 (&ldata->atomic_read_lock){+.+.}, at: n_tty_read+0x232/0x1c10 drivers/tty/n_tty.c:2156 2 locks held by getty/9058: #0: ffff8880a753d090 (&tty->ldisc_sem){++++}, at: ldsem_down_read+0x33/0x40 drivers/tty/tty_ldsem.c:340 #1: ffffc90005f652e0 (&ldata->atomic_read_lock){+.+.}, at: n_tty_read+0x232/0x1c10 drivers/tty/n_tty.c:2156 2 locks held by getty/9059: #0: ffff88808f9cb090 (&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 kworker/u5:1/4140: #0: ffff88805a975528 ((wq_completion)knbd4-recv){+.+.}, at: __write_once_size include/linux/compiler.h:226 [inline] #0: ffff88805a975528 ((wq_completion)knbd4-recv){+.+.}, at: arch_atomic64_set arch/x86/include/asm/atomic64_64.h:34 [inline] #0: ffff88805a975528 ((wq_completion)knbd4-recv){+.+.}, at: atomic64_set include/asm-generic/atomic-instrumented.h:855 [inline] #0: ffff88805a975528 ((wq_completion)knbd4-recv){+.+.}, at: atomic_long_set include/asm-generic/atomic-long.h:40 [inline] #0: ffff88805a975528 ((wq_completion)knbd4-recv){+.+.}, at: set_work_data kernel/workqueue.c:620 [inline] #0: ffff88805a975528 ((wq_completion)knbd4-recv){+.+.}, at: set_work_pool_and_clear_pending kernel/workqueue.c:647 [inline] #0: ffff88805a975528 ((wq_completion)knbd4-recv){+.+.}, at: process_one_work+0x88b/0x1740 kernel/workqueue.c:2240 #1: ffff8880a97ffdc0 ((work_completion)(&args->work)){+.+.}, at: process_one_work+0x8c1/0x1740 kernel/workqueue.c:2244 1 lock held by syz-executor.4/14936: #0: ffff88809a74c138 (&bdev->bd_mutex){+.+.}, at: blkdev_put+0x34/0x560 fs/block_dev.c:1887 1 lock held by syz-executor.4/14940: #0: ffff88809a74c138 (&bdev->bd_mutex){+.+.}, at: __blkdev_get+0x19b/0x1660 fs/block_dev.c:1553 ============================================= NMI backtrace for cpu 1 CPU: 1 PID: 1063 Comm: khungtaskd Not tainted 5.4.0-rc2+ #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:205 [inline] watchdog+0x9d0/0xef0 kernel/hung_task.c:289 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