INFO: task syz-executor.1:13917 blocked for more than 143 seconds. Not tainted 5.4.0-rc3+ #0 "echo 0 > /proc/sys/kernel/hung_task_timeout_secs" disables this message. syz-executor.1 D28368 13917 7772 0x00004004 Call Trace: context_switch kernel/sched/core.c:3384 [inline] __schedule+0x74b/0xb80 kernel/sched/core.c:4069 schedule+0x131/0x1e0 kernel/sched/core.c:4136 schedule_timeout+0x46/0x240 kernel/time/timer.c:1871 do_wait_for_common+0x2e7/0x4d0 kernel/sched/completion.c:83 __wait_for_common kernel/sched/completion.c:104 [inline] wait_for_common kernel/sched/completion.c:115 [inline] wait_for_completion+0x47/0x60 kernel/sched/completion.c:136 flush_workqueue+0x60d/0x14b0 kernel/workqueue.c:2826 nbd_start_device_ioctl drivers/block/nbd.c:1272 [inline] __nbd_ioctl drivers/block/nbd.c:1347 [inline] nbd_ioctl+0x9d2/0xac0 drivers/block/nbd.c:1387 __blkdev_driver_ioctl block/ioctl.c:304 [inline] blkdev_ioctl+0x807/0x2980 block/ioctl.c:606 block_ioctl+0xbd/0x100 fs/block_dev.c:1954 do_vfs_ioctl+0x744/0x1730 fs/ioctl.c:46 ksys_ioctl fs/ioctl.c:713 [inline] __do_sys_ioctl fs/ioctl.c:720 [inline] __se_sys_ioctl fs/ioctl.c:718 [inline] __x64_sys_ioctl+0xe3/0x120 fs/ioctl.c:718 do_syscall_64+0xf7/0x1c0 arch/x86/entry/common.c:290 entry_SYSCALL_64_after_hwframe+0x49/0xbe RIP: 0033:0x459a59 Code: 90 90 90 90 90 90 90 90 90 90 90 90 90 90 90 90 90 90 90 90 90 90 90 90 90 90 90 90 90 90 90 90 90 90 90 90 90 90 90 90 90 90 <90> 90 90 90 90 90 90 90 90 90 90 90 90 90 90 90 90 90 90 90 90 90 RSP: 002b:00007fb6576d1c78 EFLAGS: 00000246 ORIG_RAX: 0000000000000010 RAX: ffffffffffffffda RBX: 0000000000000002 RCX: 0000000000459a59 RDX: 0000000000000000 RSI: 000000000000ab03 RDI: 0000000000000005 RBP: 000000000075bf20 R08: 0000000000000000 R09: 0000000000000000 R10: 0000000000000000 R11: 0000000000000246 R12: 00007fb6576d26d4 R13: 00000000004c3381 R14: 00000000004d70b8 R15: 00000000ffffffff INFO: task syz-executor.1:13921 blocked for more than 143 seconds. Not tainted 5.4.0-rc3+ #0 "echo 0 > /proc/sys/kernel/hung_task_timeout_secs" disables this message. syz-executor.1 D26856 13921 7772 0x00004004 Call Trace: context_switch kernel/sched/core.c:3384 [inline] __schedule+0x74b/0xb80 kernel/sched/core.c:4069 schedule+0x131/0x1e0 kernel/sched/core.c:4136 io_schedule+0x8b/0x100 kernel/sched/core.c:5780 wait_on_page_bit_common+0x918/0xc90 mm/filemap.c:1174 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+0xa11/0xcb0 mm/filemap.c:2810 read_cache_page+0x4d/0x70 mm/filemap.c:2894 read_mapping_page include/linux/pagemap.h:396 [inline] read_dev_sector+0x6f/0x270 block/partition-generic.c:667 read_part_sector block/partitions/check.h:38 [inline] adfspart_check_ICS+0xbd/0xa70 block/partitions/acorn.c:361 check_partition+0x368/0x640 block/partitions/check.c:167 rescan_partitions+0x1a8/0xec0 block/partition-generic.c:531 __blkdev_get+0xd28/0x12f0 fs/block_dev.c:1637 blkdev_get+0x34b/0x3f0 fs/block_dev.c:1707 blkdev_open+0x1e3/0x2c0 fs/block_dev.c:1846 do_dentry_open+0x740/0x10c0 fs/open.c:797 vfs_open+0x73/0x80 fs/open.c:914 do_last fs/namei.c:3408 [inline] path_openat+0x1397/0x4420 fs/namei.c:3525 do_filp_open+0x192/0x3d0 fs/namei.c:3555 do_sys_open+0x29f/0x560 fs/open.c:1097 __do_sys_open fs/open.c:1115 [inline] __se_sys_open fs/open.c:1110 [inline] __x64_sys_open+0x87/0x90 fs/open.c:1110 do_syscall_64+0xf7/0x1c0 arch/x86/entry/common.c:290 entry_SYSCALL_64_after_hwframe+0x49/0xbe RIP: 0033:0x413941 Code: 48 8b 1b 48 89 5c 24 18 48 89 3c 24 89 4c 24 08 48 89 44 24 10 48 8b 44 24 68 48 89 44 24 20 48 89 54 24 28 48 8d 46 04 48 89 <44> 24 30 e8 27 01 00 00 48 8b 6c 24 48 48 83 c4 50 c3 48 8b 03 48 RSP: 002b:00007fb6576b07a0 EFLAGS: 00000293 ORIG_RAX: 0000000000000002 RAX: ffffffffffffffda RBX: 6666666666666667 RCX: 0000000000413941 RDX: 0000000000000000 RSI: 0000000000000000 RDI: 00007fb6576b0850 RBP: 000000000075bfc8 R08: 000000000000000f R09: 0000000000000000 R10: 0000000000000000 R11: 0000000000000293 R12: 00007fb6576b16d4 R13: 00000000004c9199 R14: 00000000004e07d8 R15: 00000000ffffffff Showing all locks held in the system: 3 locks held by kworker/u4:1/21: #0: ffff8880aea34998 (&rq->lock){-.-.}, at: newidle_balance+0x629/0xb60 kernel/sched/fair.c:9825 #1: ffffffff888d3f80 (rcu_read_lock){....}, at: rcu_lock_acquire+0x4/0x30 include/linux/rcupdate.h:207 #2: ffff8880aea24a98 (&base->lock){-.-.}, at: lock_timer_base kernel/time/timer.c:936 [inline] #2: ffff8880aea24a98 (&base->lock){-.-.}, at: __mod_timer+0x1a1/0x1590 kernel/time/timer.c:1008 1 lock held by khungtaskd/1069: #0: ffffffff888d3f80 (rcu_read_lock){....}, at: rcu_lock_acquire+0x4/0x30 include/linux/rcupdate.h:207 2 locks held by getty/7731: #0: ffff8880a457f090 (&tty->ldisc_sem){++++}, at: tty_ldisc_ref_wait+0x25/0x70 drivers/tty/tty_ldisc.c:272 #1: ffffc90005f012e0 (&ldata->atomic_read_lock){+.+.}, at: n_tty_read+0x221/0x1b00 drivers/tty/n_tty.c:2156 2 locks held by getty/7732: #0: ffff8880a8802090 (&tty->ldisc_sem){++++}, at: tty_ldisc_ref_wait+0x25/0x70 drivers/tty/tty_ldisc.c:272 #1: ffffc90005f0d2e0 (&ldata->atomic_read_lock){+.+.}, at: n_tty_read+0x221/0x1b00 drivers/tty/n_tty.c:2156 2 locks held by getty/7733: #0: ffff88809b829090 (&tty->ldisc_sem){++++}, at: tty_ldisc_ref_wait+0x25/0x70 drivers/tty/tty_ldisc.c:272 #1: ffffc90005f052e0 (&ldata->atomic_read_lock){+.+.}, at: n_tty_read+0x221/0x1b00 drivers/tty/n_tty.c:2156 2 locks held by getty/7734: #0: ffff88808e0c7090 (&tty->ldisc_sem){++++}, at: tty_ldisc_ref_wait+0x25/0x70 drivers/tty/tty_ldisc.c:272 #1: ffffc90005f092e0 (&ldata->atomic_read_lock){+.+.}, at: n_tty_read+0x221/0x1b00 drivers/tty/n_tty.c:2156 2 locks held by getty/7735: #0: ffff88809070e090 (&tty->ldisc_sem){++++}, at: tty_ldisc_ref_wait+0x25/0x70 drivers/tty/tty_ldisc.c:272 #1: ffffc90005ef52e0 (&ldata->atomic_read_lock){+.+.}, at: n_tty_read+0x221/0x1b00 drivers/tty/n_tty.c:2156 2 locks held by getty/7736: #0: ffff8880964bd090 (&tty->ldisc_sem){++++}, at: tty_ldisc_ref_wait+0x25/0x70 drivers/tty/tty_ldisc.c:272 #1: ffffc90005f112e0 (&ldata->atomic_read_lock){+.+.}, at: n_tty_read+0x221/0x1b00 drivers/tty/n_tty.c:2156 2 locks held by getty/7737: #0: ffff88808eb2a090 (&tty->ldisc_sem){++++}, at: tty_ldisc_ref_wait+0x25/0x70 drivers/tty/tty_ldisc.c:272 #1: ffffc90005ee12e0 (&ldata->atomic_read_lock){+.+.}, at: n_tty_read+0x221/0x1b00 drivers/tty/n_tty.c:2156 2 locks held by kworker/u5:2/9073: #0: ffff8880a8ae6928 ((wq_completion)knbd1-recv){+.+.}, at: spin_unlock_irq include/linux/spinlock.h:388 [inline] #0: ffff8880a8ae6928 ((wq_completion)knbd1-recv){+.+.}, at: process_one_work+0x75d/0x10e0 kernel/workqueue.c:2242 #1: ffff8880593efd78 ((work_completion)(&args->work)){+.+.}, at: process_one_work+0x79f/0x10e0 kernel/workqueue.c:2244 1 lock held by syz-executor.1/13921: #0: ffff888094f41678 (&bdev->bd_mutex){+.+.}, at: __blkdev_get+0x1de/0x12f0 fs/block_dev.c:1553 ============================================= NMI backtrace for cpu 1 CPU: 1 PID: 1069 Comm: khungtaskd Not tainted 5.4.0-rc3+ #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+0x1d8/0x2f8 lib/dump_stack.c:113 nmi_cpu_backtrace+0xaf/0x1a0 lib/nmi_backtrace.c:101 nmi_trigger_cpumask_backtrace+0x174/0x290 lib/nmi_backtrace.c:62 arch_trigger_cpumask_backtrace+0x10/0x20 arch/x86/kernel/apic/hw_nmi.c:38 trigger_all_cpu_backtrace+0x17/0x20 include/linux/nmi.h:146 check_hung_uninterruptible_tasks kernel/hung_task.c:205 [inline] watchdog+0xbb9/0xbd0 kernel/hung_task.c:289 kthread+0x332/0x350 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