====================================================== WARNING: possible circular locking dependency detected syzkaller #0 Tainted: G W L ------------------------------------------------------ syz.0.420/5079 is trying to acquire lock: ffffaf801f26c468 (&nsock->tx_lock){+.+.}-{4:4}, at: nbd_handle_cmd drivers/block/nbd.c:1143 [inline] ffffaf801f26c468 (&nsock->tx_lock){+.+.}-{4:4}, at: nbd_queue_rq+0x372/0xe44 drivers/block/nbd.c:1207 but task is already holding lock: ffffaf8033d47338 (&cmd->lock){+.+.}-{4:4}, at: nbd_queue_rq+0xc4/0xe44 drivers/block/nbd.c:1199 which lock already depends on the new lock. the existing dependency chain (in reverse order) is: -> #6 (&cmd->lock){+.+.}-{4:4}: lock_acquire kernel/locking/lockdep.c:5868 [inline] lock_acquire+0x246/0x500 kernel/locking/lockdep.c:5825 __mutex_lock_common kernel/locking/mutex.c:646 [inline] __mutex_lock+0x164/0x18f4 kernel/locking/mutex.c:820 mutex_lock_nested+0x14/0x1c kernel/locking/mutex.c:873 nbd_queue_rq+0xc4/0xe44 drivers/block/nbd.c:1199 blk_mq_dispatch_rq_list+0x3cc/0x1ac0 block/blk-mq.c:2148 __blk_mq_do_dispatch_sched block/blk-mq-sched.c:168 [inline] blk_mq_do_dispatch_sched block/blk-mq-sched.c:182 [inline] __blk_mq_sched_dispatch_requests+0xe12/0x13cc block/blk-mq-sched.c:307 blk_mq_sched_dispatch_requests+0xb2/0x174 block/blk-mq-sched.c:329 blk_mq_run_hw_queue+0x274/0x6ec block/blk-mq.c:2386 blk_mq_dispatch_list+0x53e/0x1430 block/blk-mq.c:2949 blk_mq_flush_plug_list block/blk-mq.c:2997 [inline] blk_mq_flush_plug_list+0x114/0x55c block/blk-mq.c:2969 __blk_flush_plug+0x270/0x464 block/blk-core.c:1230 blk_finish_plug block/blk-core.c:1257 [inline] blk_finish_plug block/blk-core.c:1254 [inline] __submit_bio+0x42e/0x504 block/blk-core.c:649 __submit_bio_noacct_mq block/blk-core.c:722 [inline] submit_bio_noacct_nocheck+0x458/0xdec block/blk-core.c:753 submit_bio_noacct+0x6fe/0x2168 block/blk-core.c:884 submit_bio+0xb6/0x5b8 block/blk-core.c:926 blk_crypto_submit_bio include/linux/blk-crypto.h:203 [inline] submit_bh_wbc+0x4d8/0x6bc fs/buffer.c:2737 submit_bh fs/buffer.c:2742 [inline] block_read_full_folio+0x3f2/0x788 fs/buffer.c:2358 blkdev_read_folio+0x26/0x30 block/fops.c:494 filemap_read_folio+0xc2/0x270 mm/filemap.c:2502 do_read_cache_folio+0x22e/0x518 mm/filemap.c:4107 read_cache_folio+0x4e/0x68 mm/filemap.c:4139 read_mapping_folio include/linux/pagemap.h:1017 [inline] read_part_sector+0xbc/0x408 block/partitions/core.c:724 read_lba+0x1b6/0x32c block/partitions/efi.c:247 find_valid_gpt.constprop.0+0x212/0x21ec block/partitions/efi.c:602 efi_partition+0xfa/0xae0 block/partitions/efi.c:719 check_partition block/partitions/core.c:143 [inline] blk_add_partitions block/partitions/core.c:591 [inline] bdev_disk_changed+0x5b8/0x11b4 block/partitions/core.c:695 blkdev_get_whole+0x168/0x25c block/bdev.c:756 bdev_open+0x288/0xcc4 block/bdev.c:965 blkdev_open+0x2ec/0x454 block/fops.c:697 do_dentry_open+0x418/0x1170 fs/open.c:947 vfs_open+0xba/0x3a8 fs/open.c:1079 do_open fs/namei.c:4699 [inline] path_openat+0x144e/0x2f28 fs/namei.c:4858 do_file_open+0x1ae/0x398 fs/namei.c:4887 do_sys_openat2+0xfe/0x1c0 fs/open.c:1364 do_sys_open fs/open.c:1370 [inline] __do_sys_openat fs/open.c:1386 [inline] __se_sys_openat fs/open.c:1381 [inline] __riscv_sys_openat+0x122/0x1e4 fs/open.c:1381 syscall_handler+0x92/0x114 arch/riscv/include/asm/syscall.h:112 do_trap_ecall_u+0x3dc/0x61c arch/riscv/kernel/traps.c:342 handle_exception+0x15e/0x16a arch/riscv/kernel/entry.S:232 -> #5 (set->srcu){.+.+}-{0:0}: lock_sync+0xea/0x1cc kernel/locking/lockdep.c:5916 srcu_lock_sync include/linux/srcu.h:199 [inline] __synchronize_srcu+0xd4/0x2a8 kernel/rcu/srcutree.c:1481 synchronize_srcu_expedited kernel/rcu/srcutree.c:1521 [inline] synchronize_srcu+0x194/0x9e4 kernel/rcu/srcutree.c:1577 blk_mq_wait_quiesce_done block/blk-mq.c:284 [inline] blk_mq_wait_quiesce_done block/blk-mq.c:281 [inline] blk_mq_quiesce_queue block/blk-mq.c:304 [inline] blk_mq_quiesce_queue+0x124/0x194 block/blk-mq.c:299 elevator_switch+0x16a/0x4e4 block/elevator.c:576 elevator_change+0x2f4/0x4ac block/elevator.c:681 elevator_set_default+0x280/0x370 block/elevator.c:754 blk_register_queue+0x40c/0x598 block/blk-sysfs.c:987 __add_disk+0x69a/0xda4 block/genhd.c:528 add_disk_fwnode+0xe8/0x48c block/genhd.c:597 device_add_disk+0x28/0x38 block/genhd.c:627 add_disk include/linux/blkdev.h:794 [inline] nbd_dev_add+0x692/0xaec drivers/block/nbd.c:1984 nbd_init+0x3d4/0x3f8 drivers/block/nbd.c:2692 do_one_initcall+0x18c/0xcc8 init/main.c:1392 do_initcall_level init/main.c:1454 [inline] do_initcalls init/main.c:1470 [inline] do_basic_setup init/main.c:1490 [inline] kernel_init_freeable+0x6d2/0x7bc init/main.c:1703 kernel_init+0x28/0x240 init/main.c:1593 ret_from_fork_kernel+0x94/0xef8 arch/riscv/kernel/process.c:230 ret_from_fork_kernel_asm+0x16/0x18 arch/riscv/kernel/entry.S:363 -> #4 (&q->elevator_lock){+.+.}-{4:4}: lock_acquire kernel/locking/lockdep.c:5868 [inline] lock_acquire+0x246/0x500 kernel/locking/lockdep.c:5825 __mutex_lock_common kernel/locking/mutex.c:646 [inline] __mutex_lock+0x164/0x18f4 kernel/locking/mutex.c:820 mutex_lock_nested+0x14/0x1c kernel/locking/mutex.c:873 elevator_change+0x192/0x4ac block/elevator.c:679 elevator_set_none+0xa8/0x120 block/elevator.c:769 blk_mq_elv_switch_none block/blk-mq.c:5131 [inline] __blk_mq_update_nr_hw_queues block/blk-mq.c:5176 [inline] blk_mq_update_nr_hw_queues+0x43a/0x13a0 block/blk-mq.c:5241 nbd_start_device+0x156/0xb74 drivers/block/nbd.c:1489 nbd_genl_connect+0xe74/0x1a4c drivers/block/nbd.c:2239 genl_family_rcv_msg_doit+0x1f6/0x2d8 net/netlink/genetlink.c:1114 genl_family_rcv_msg net/netlink/genetlink.c:1194 [inline] genl_rcv_msg+0x4b2/0x73c net/netlink/genetlink.c:1209 netlink_rcv_skb+0x1e8/0x394 net/netlink/af_netlink.c:2550 genl_rcv+0x32/0x4c net/netlink/genetlink.c:1218 netlink_unicast_kernel net/netlink/af_netlink.c:1318 [inline] netlink_unicast+0x4f6/0x7c0 net/netlink/af_netlink.c:1344 netlink_sendmsg+0x7e0/0xd64 net/netlink/af_netlink.c:1894 sock_sendmsg_nosec net/socket.c:787 [inline] __sock_sendmsg+0xca/0x160 net/socket.c:802 ____sys_sendmsg+0x636/0x794 net/socket.c:2698 ___sys_sendmsg+0x1a4/0x1e8 net/socket.c:2752 __sys_sendmsg+0x18e/0x234 net/socket.c:2784 __do_sys_sendmsg net/socket.c:2789 [inline] __se_sys_sendmsg net/socket.c:2787 [inline] __riscv_sys_sendmsg+0x70/0xa4 net/socket.c:2787 syscall_handler+0x92/0x114 arch/riscv/include/asm/syscall.h:112 do_trap_ecall_u+0x3dc/0x61c arch/riscv/kernel/traps.c:342 handle_exception+0x15e/0x16a arch/riscv/kernel/entry.S:232 -> #3 (&q->q_usage_counter(io)#19){++++}-{0:0}: lock_acquire kernel/locking/lockdep.c:5868 [inline] lock_acquire+0x246/0x500 kernel/locking/lockdep.c:5825 blk_alloc_queue+0x5b4/0x6f4 block/blk-core.c:461 blk_mq_alloc_queue+0x15e/0x250 block/blk-mq.c:4450 __blk_mq_alloc_disk+0x2a/0xd8 block/blk-mq.c:4497 nbd_dev_add+0x426/0xaec drivers/block/nbd.c:1954 nbd_init+0x3d4/0x3f8 drivers/block/nbd.c:2692 do_one_initcall+0x18c/0xcc8 init/main.c:1392 do_initcall_level init/main.c:1454 [inline] do_initcalls init/main.c:1470 [inline] do_basic_setup init/main.c:1490 [inline] kernel_init_freeable+0x6d2/0x7bc init/main.c:1703 kernel_init+0x28/0x240 init/main.c:1593 ret_from_fork_kernel+0x94/0xef8 arch/riscv/kernel/process.c:230 ret_from_fork_kernel_asm+0x16/0x18 arch/riscv/kernel/entry.S:363 -> #2 (fs_reclaim){+.+.}-{0:0}: lock_acquire kernel/locking/lockdep.c:5868 [inline] lock_acquire+0x246/0x500 kernel/locking/lockdep.c:5825 __fs_reclaim_acquire mm/page_alloc.c:4325 [inline] fs_reclaim_acquire+0xc6/0x100 mm/page_alloc.c:4339 might_alloc include/linux/sched/mm.h:317 [inline] slab_pre_alloc_hook mm/slub.c:4520 [inline] slab_alloc_node mm/slub.c:4875 [inline] kmem_cache_alloc_node_noprof+0x40/0x6e8 mm/slub.c:4950 __alloc_skb+0x17c/0x778 net/core/skbuff.c:702 alloc_skb_fclone include/linux/skbuff.h:1433 [inline] tcp_stream_alloc_skb+0x2e/0x4d8 net/ipv4/tcp.c:935 tcp_sendmsg_locked+0xe1a/0x3f98 net/ipv4/tcp.c:1260 tcp_sendmsg+0x32/0x50 net/ipv4/tcp.c:1455 inet_sendmsg+0x9a/0xd8 net/ipv4/af_inet.c:866 sock_sendmsg_nosec net/socket.c:787 [inline] __sock_sendmsg+0xca/0x160 net/socket.c:802 sock_write_iter+0x298/0x3e8 net/socket.c:1254 new_sync_write fs/read_write.c:595 [inline] vfs_write+0x648/0xc78 fs/read_write.c:688 ksys_write+0x1f4/0x238 fs/read_write.c:740 __do_sys_write fs/read_write.c:751 [inline] __se_sys_write fs/read_write.c:748 [inline] __riscv_sys_write+0x6e/0x94 fs/read_write.c:748 syscall_handler+0x92/0x114 arch/riscv/include/asm/syscall.h:112 do_trap_ecall_u+0x3dc/0x61c arch/riscv/kernel/traps.c:342 handle_exception+0x15e/0x16a arch/riscv/kernel/entry.S:232 -> #1 (sk_lock-AF_INET){+.+.}-{0:0}: lock_acquire kernel/locking/lockdep.c:5868 [inline] lock_acquire+0x246/0x500 kernel/locking/lockdep.c:5825 lock_sock_nested+0x38/0xf8 net/core/sock.c:3783 lock_sock include/net/sock.h:1713 [inline] inet_shutdown+0x68/0x3c0 net/ipv4/af_inet.c:915 kernel_sock_shutdown+0x58/0x7c net/socket.c:3785 nbd_mark_nsock_dead+0xaa/0x510 drivers/block/nbd.c:318 sock_shutdown+0x144/0x238 drivers/block/nbd.c:411 nbd_clear_sock drivers/block/nbd.c:1427 [inline] nbd_clear_sock_ioctl drivers/block/nbd.c:1575 [inline] __nbd_ioctl drivers/block/nbd.c:1603 [inline] nbd_ioctl+0x22c/0xbd4 drivers/block/nbd.c:1663 blkdev_ioctl+0x4cc/0x12e4 block/ioctl.c:797 vfs_ioctl fs/ioctl.c:51 [inline] __do_sys_ioctl fs/ioctl.c:597 [inline] __se_sys_ioctl fs/ioctl.c:583 [inline] __riscv_sys_ioctl+0x17c/0x1e4 fs/ioctl.c:583 syscall_handler+0x92/0x114 arch/riscv/include/asm/syscall.h:112 do_trap_ecall_u+0x3dc/0x61c arch/riscv/kernel/traps.c:342 handle_exception+0x15e/0x16a arch/riscv/kernel/entry.S:232 -> #0 (&nsock->tx_lock){+.+.}-{4:4}: check_noncircular+0x138/0x14c kernel/locking/lockdep.c:2175 check_prev_add kernel/locking/lockdep.c:3165 [inline] check_prevs_add kernel/locking/lockdep.c:3284 [inline] validate_chain kernel/locking/lockdep.c:3908 [inline] __lock_acquire+0xe9c/0x25ac kernel/locking/lockdep.c:5237 lock_acquire kernel/locking/lockdep.c:5868 [inline] lock_acquire+0x246/0x500 kernel/locking/lockdep.c:5825 __mutex_lock_common kernel/locking/mutex.c:646 [inline] __mutex_lock+0x164/0x18f4 kernel/locking/mutex.c:820 mutex_lock_nested+0x14/0x1c kernel/locking/mutex.c:873 nbd_handle_cmd drivers/block/nbd.c:1143 [inline] nbd_queue_rq+0x372/0xe44 drivers/block/nbd.c:1207 blk_mq_dispatch_rq_list+0x3cc/0x1ac0 block/blk-mq.c:2148 __blk_mq_do_dispatch_sched block/blk-mq-sched.c:168 [inline] blk_mq_do_dispatch_sched block/blk-mq-sched.c:182 [inline] __blk_mq_sched_dispatch_requests+0xe12/0x13cc block/blk-mq-sched.c:307 blk_mq_sched_dispatch_requests+0xb2/0x174 block/blk-mq-sched.c:329 blk_mq_run_hw_queue+0x274/0x6ec block/blk-mq.c:2386 blk_mq_dispatch_list+0x53e/0x1430 block/blk-mq.c:2949 blk_mq_flush_plug_list block/blk-mq.c:2997 [inline] blk_mq_flush_plug_list+0x114/0x55c block/blk-mq.c:2969 __blk_flush_plug+0x270/0x464 block/blk-core.c:1230 blk_finish_plug block/blk-core.c:1257 [inline] blk_finish_plug block/blk-core.c:1254 [inline] __submit_bio+0x42e/0x504 block/blk-core.c:649 __submit_bio_noacct_mq block/blk-core.c:722 [inline] submit_bio_noacct_nocheck+0x458/0xdec block/blk-core.c:753 submit_bio_noacct+0x6fe/0x2168 block/blk-core.c:884 submit_bio+0xb6/0x5b8 block/blk-core.c:926 blk_crypto_submit_bio include/linux/blk-crypto.h:203 [inline] submit_bh_wbc+0x4d8/0x6bc fs/buffer.c:2737 submit_bh fs/buffer.c:2742 [inline] block_read_full_folio+0x3f2/0x788 fs/buffer.c:2358 blkdev_read_folio+0x26/0x30 block/fops.c:494 filemap_read_folio+0xc2/0x270 mm/filemap.c:2502 do_read_cache_folio+0x22e/0x518 mm/filemap.c:4107 read_cache_folio+0x4e/0x68 mm/filemap.c:4139 read_mapping_folio include/linux/pagemap.h:1017 [inline] read_part_sector+0xbc/0x408 block/partitions/core.c:724 read_lba+0x1b6/0x32c block/partitions/efi.c:247 find_valid_gpt.constprop.0+0x212/0x21ec block/partitions/efi.c:602 efi_partition+0xfa/0xae0 block/partitions/efi.c:719 check_partition block/partitions/core.c:143 [inline] blk_add_partitions block/partitions/core.c:591 [inline] bdev_disk_changed+0x5b8/0x11b4 block/partitions/core.c:695 blkdev_get_whole+0x168/0x25c block/bdev.c:756 bdev_open+0x288/0xcc4 block/bdev.c:965 blkdev_open+0x2ec/0x454 block/fops.c:697 do_dentry_open+0x418/0x1170 fs/open.c:947 vfs_open+0xba/0x3a8 fs/open.c:1079 do_open fs/namei.c:4699 [inline] path_openat+0x144e/0x2f28 fs/namei.c:4858 do_file_open+0x1ae/0x398 fs/namei.c:4887 do_sys_openat2+0xfe/0x1c0 fs/open.c:1364 do_sys_open fs/open.c:1370 [inline] __do_sys_openat fs/open.c:1386 [inline] __se_sys_openat fs/open.c:1381 [inline] __riscv_sys_openat+0x122/0x1e4 fs/open.c:1381 syscall_handler+0x92/0x114 arch/riscv/include/asm/syscall.h:112 do_trap_ecall_u+0x3dc/0x61c arch/riscv/kernel/traps.c:342 handle_exception+0x15e/0x16a arch/riscv/kernel/entry.S:232 other info that might help us debug this: Chain exists of: &nsock->tx_lock --> set->srcu --> &cmd->lock Possible unsafe locking scenario: CPU0 CPU1 ---- ---- lock(&cmd->lock); lock(set->srcu); lock(&cmd->lock); lock(&nsock->tx_lock); *** DEADLOCK *** 3 locks held by syz.0.420/5079: #0: ffffaf801a8d1350 (&disk->open_mutex){+.+.}-{4:4}, at: bdev_open+0x3c4/0xcc4 block/bdev.c:953 #1: ffffaf801a0b8a18 (set->srcu){.+.+}-{0:0}, at: blk_mq_run_hw_queue+0x22c/0x6ec block/blk-mq.c:2386 #2: ffffaf8033d47338 (&cmd->lock){+.+.}-{4:4}, at: nbd_queue_rq+0xc4/0xe44 drivers/block/nbd.c:1199 stack backtrace: CPU: 1 UID: 0 PID: 5079 Comm: syz.0.420 Tainted: G W L syzkaller #0 PREEMPT Tainted: [W]=WARN, [L]=SOFTLOCKUP Hardware name: riscv-virtio,qemu (DT) Call Trace: [] dump_backtrace+0x2e/0x3c arch/riscv/kernel/stacktrace.c:149 [] show_stack+0x30/0x3c arch/riscv/kernel/stacktrace.c:155 [] __dump_stack lib/dump_stack.c:94 [inline] [] dump_stack_lvl+0x114/0x1ac lib/dump_stack.c:120 [] dump_stack+0x1c/0x28 lib/dump_stack.c:129 [] print_circular_bug+0x250/0x29c kernel/locking/lockdep.c:2043 [] check_noncircular+0x138/0x14c kernel/locking/lockdep.c:2175 [] check_prev_add kernel/locking/lockdep.c:3165 [inline] [] check_prevs_add kernel/locking/lockdep.c:3284 [inline] [] validate_chain kernel/locking/lockdep.c:3908 [inline] [] __lock_acquire+0xe9c/0x25ac kernel/locking/lockdep.c:5237 [] lock_acquire kernel/locking/lockdep.c:5868 [inline] [] lock_acquire+0x246/0x500 kernel/locking/lockdep.c:5825 [] __mutex_lock_common kernel/locking/mutex.c:646 [inline] [] __mutex_lock+0x164/0x18f4 kernel/locking/mutex.c:820 [] mutex_lock_nested+0x14/0x1c kernel/locking/mutex.c:873 [] nbd_handle_cmd drivers/block/nbd.c:1143 [inline] [] nbd_queue_rq+0x372/0xe44 drivers/block/nbd.c:1207 [] blk_mq_dispatch_rq_list+0x3cc/0x1ac0 block/blk-mq.c:2148 [] __blk_mq_do_dispatch_sched block/blk-mq-sched.c:168 [inline] [] blk_mq_do_dispatch_sched block/blk-mq-sched.c:182 [inline] [] __blk_mq_sched_dispatch_requests+0xe12/0x13cc block/blk-mq-sched.c:307 [] blk_mq_sched_dispatch_requests+0xb2/0x174 block/blk-mq-sched.c:329 [] blk_mq_run_hw_queue+0x274/0x6ec block/blk-mq.c:2386 [] blk_mq_dispatch_list+0x53e/0x1430 block/blk-mq.c:2949 [] blk_mq_flush_plug_list block/blk-mq.c:2997 [inline] [] blk_mq_flush_plug_list+0x114/0x55c block/blk-mq.c:2969 [] __blk_flush_plug+0x270/0x464 block/blk-core.c:1230 [] blk_finish_plug block/blk-core.c:1257 [inline] [] blk_finish_plug block/blk-core.c:1254 [inline] [] __submit_bio+0x42e/0x504 block/blk-core.c:649 [] __submit_bio_noacct_mq block/blk-core.c:722 [inline] [] submit_bio_noacct_nocheck+0x458/0xdec block/blk-core.c:753 [] submit_bio_noacct+0x6fe/0x2168 block/blk-core.c:884 [] submit_bio+0xb6/0x5b8 block/blk-core.c:926 [] blk_crypto_submit_bio include/linux/blk-crypto.h:203 [inline] [] submit_bh_wbc+0x4d8/0x6bc fs/buffer.c:2737 [] submit_bh fs/buffer.c:2742 [inline] [] block_read_full_folio+0x3f2/0x788 fs/buffer.c:2358 [] blkdev_read_folio+0x26/0x30 block/fops.c:494 [] filemap_read_folio+0xc2/0x270 mm/filemap.c:2502 [] do_read_cache_folio+0x22e/0x518 mm/filemap.c:4107 [] read_cache_folio+0x4e/0x68 mm/filemap.c:4139 [] read_mapping_folio include/linux/pagemap.h:1017 [inline] [] read_part_sector+0xbc/0x408 block/partitions/core.c:724 [] read_lba+0x1b6/0x32c block/partitions/efi.c:247 [] find_valid_gpt.constprop.0+0x212/0x21ec block/partitions/efi.c:602 [] efi_partition+0xfa/0xae0 block/partitions/efi.c:719 [] check_partition block/partitions/core.c:143 [inline] [] blk_add_partitions block/partitions/core.c:591 [inline] [] bdev_disk_changed+0x5b8/0x11b4 block/partitions/core.c:695 [] blkdev_get_whole+0x168/0x25c block/bdev.c:756 [] bdev_open+0x288/0xcc4 block/bdev.c:965 [] blkdev_open+0x2ec/0x454 block/fops.c:697 [] do_dentry_open+0x418/0x1170 fs/open.c:947 [] vfs_open+0xba/0x3a8 fs/open.c:1079 [] do_open fs/namei.c:4699 [inline] [] path_openat+0x144e/0x2f28 fs/namei.c:4858 [] do_file_open+0x1ae/0x398 fs/namei.c:4887 [] do_sys_openat2+0xfe/0x1c0 fs/open.c:1364 [] do_sys_open fs/open.c:1370 [inline] [] __do_sys_openat fs/open.c:1386 [inline] [] __se_sys_openat fs/open.c:1381 [inline] [] __riscv_sys_openat+0x122/0x1e4 fs/open.c:1381 [] syscall_handler+0x92/0x114 arch/riscv/include/asm/syscall.h:112 [] do_trap_ecall_u+0x3dc/0x61c arch/riscv/kernel/traps.c:342 [] handle_exception+0x15e/0x16a arch/riscv/kernel/entry.S:232 I/O error, dev nbd0, sector 6 op 0x0:(READ) flags 0x0 phys_seg 1 prio class 2 Buffer I/O error on dev nbd0, logical block 3, async page read I/O error, dev nbd0, sector 0 op 0x0:(READ) flags 0x0 phys_seg 1 prio class 2 Buffer I/O error on dev nbd0, logical block 0, async page read I/O error, dev nbd0, sector 2 op 0x0:(READ) flags 0x0 phys_seg 1 prio class 2 Buffer I/O error on dev nbd0, logical block 1, async page read I/O error, dev nbd0, sector 4 op 0x0:(READ) flags 0x0 phys_seg 1 prio class 2 Buffer I/O error on dev nbd0, logical block 2, async page read I/O error, dev nbd0, sector 6 op 0x0:(READ) flags 0x0 phys_seg 1 prio class 2 Buffer I/O error on dev nbd0, logical block 3, async page read nbd0: unable to read partition table