====================================================== WARNING: possible circular locking dependency detected syzkaller #0 Tainted: G L ------------------------------------------------------ udevd/21901 is trying to acquire lock: ffff00000ef89270 (&nsock->tx_lock){+.+.}-{4:4}, at: nbd_handle_cmd drivers/block/nbd.c:1143 [inline] ffff00000ef89270 (&nsock->tx_lock){+.+.}-{4:4}, at: nbd_queue_rq+0x2e4/0xb3c drivers/block/nbd.c:1207 but task is already holding lock: ffff000024008180 (&cmd->lock){+.+.}-{4:4}, at: nbd_queue_rq+0xa8/0xb3c 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+0x3f0/0x46c kernel/locking/lockdep.c:5825 __mutex_lock_common kernel/locking/mutex.c:614 [inline] __mutex_lock+0x14c/0x1590 kernel/locking/mutex.c:776 mutex_lock_nested+0x24/0x30 kernel/locking/mutex.c:828 nbd_queue_rq+0xa8/0xb3c drivers/block/nbd.c:1199 blk_mq_dispatch_rq_list+0x2e0/0x1778 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+0xc50/0xe60 block/blk-mq-sched.c:307 blk_mq_sched_dispatch_requests+0x7c/0x114 block/blk-mq-sched.c:329 blk_mq_run_hw_queue+0x204/0x4a4 block/blk-mq.c:2386 blk_mq_dispatch_list+0x36c/0xa90 block/blk-mq.c:2949 blk_mq_flush_plug_list block/blk-mq.c:2997 [inline] blk_mq_flush_plug_list+0xf0/0x524 block/blk-mq.c:2969 __blk_flush_plug+0x210/0x3d0 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+0x388/0x458 block/blk-core.c:649 __submit_bio_noacct_mq block/blk-core.c:722 [inline] submit_bio_noacct_nocheck+0x5bc/0xb00 block/blk-core.c:753 submit_bio_noacct+0x34c/0x1980 block/blk-core.c:884 submit_bio+0x334/0x660 block/blk-core.c:926 blk_crypto_submit_bio include/linux/blk-crypto.h:203 [inline] submit_bh_wbc+0x328/0x4a4 fs/buffer.c:2821 submit_bh fs/buffer.c:2826 [inline] block_read_full_folio+0x2a8/0x680 fs/buffer.c:2444 blkdev_read_folio+0x1c/0x28 block/fops.c:494 filemap_read_folio+0xb0/0x1fc mm/filemap.c:2501 do_read_cache_folio+0x1bc/0x364 mm/filemap.c:4101 read_cache_folio+0x44/0x6c mm/filemap.c:4133 read_mapping_folio include/linux/pagemap.h:1017 [inline] read_part_sector+0xa4/0x5f8 block/partitions/core.c:723 read_lba+0x158/0x2e8 block/partitions/efi.c:247 find_valid_gpt block/partitions/efi.c:602 [inline] efi_partition+0x1d4/0x217c block/partitions/efi.c:719 check_partition block/partitions/core.c:142 [inline] blk_add_partitions block/partitions/core.c:590 [inline] bdev_disk_changed+0x520/0x1028 block/partitions/core.c:694 blkdev_get_whole+0x144/0x1f0 block/bdev.c:764 bdev_open+0x1d4/0xa70 block/bdev.c:973 blkdev_open+0x270/0x3f0 block/fops.c:697 do_dentry_open+0x388/0x10e4 fs/open.c:949 vfs_open+0x5c/0x2fc fs/open.c:1081 do_open fs/namei.c:4677 [inline] path_openat+0x1734/0x2654 fs/namei.c:4836 do_file_open+0x18c/0x37c fs/namei.c:4865 do_sys_openat2+0xdc/0x184 fs/open.c:1366 do_sys_open fs/open.c:1372 [inline] __do_sys_openat fs/open.c:1388 [inline] __se_sys_openat fs/open.c:1383 [inline] __arm64_sys_openat+0x130/0x1d0 fs/open.c:1383 __invoke_syscall arch/arm64/kernel/syscall.c:35 [inline] invoke_syscall+0x70/0x260 arch/arm64/kernel/syscall.c:49 el0_svc_common.constprop.0+0xac/0x230 arch/arm64/kernel/syscall.c:132 do_el0_svc+0x40/0x58 arch/arm64/kernel/syscall.c:151 el0_svc+0x54/0x29c arch/arm64/kernel/entry-common.c:724 el0t_64_sync_handler+0xa0/0xe4 arch/arm64/kernel/entry-common.c:743 el0t_64_sync+0x198/0x19c arch/arm64/kernel/entry.S:596 -> #5 (set->srcu){.+.+}-{0:0}: lock_sync+0xf0/0x16c kernel/locking/lockdep.c:5916 srcu_lock_sync include/linux/srcu.h:199 [inline] __synchronize_srcu+0xac/0x288 kernel/rcu/srcutree.c:1481 synchronize_srcu_expedited kernel/rcu/srcutree.c:1521 [inline] synchronize_srcu+0x168/0x7d0 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+0xf4/0x160 block/blk-mq.c:299 elevator_switch+0x118/0x430 block/elevator.c:576 elevator_change+0x294/0x420 block/elevator.c:681 elevator_set_default+0x210/0x2b8 block/elevator.c:754 blk_register_queue+0x31c/0x484 block/blk-sysfs.c:946 __add_disk+0x510/0xb48 block/genhd.c:528 add_disk_fwnode+0x110/0x4c4 block/genhd.c:597 device_add_disk+0x14/0x20 block/genhd.c:627 add_disk include/linux/blkdev.h:785 [inline] nbd_dev_add+0x5f8/0x9c0 drivers/block/nbd.c:1984 nbd_init+0x16c/0x18c drivers/block/nbd.c:2692 do_one_initcall+0x134/0xb40 init/main.c:1382 do_initcall_level init/main.c:1444 [inline] do_initcalls init/main.c:1460 [inline] do_basic_setup init/main.c:1479 [inline] kernel_init_freeable+0x5e8/0x66c init/main.c:1692 kernel_init+0x24/0x150 init/main.c:1582 ret_from_fork+0x10/0x20 arch/arm64/kernel/entry.S:860 -> #4 (&q->elevator_lock){+.+.}-{4:4}: lock_acquire kernel/locking/lockdep.c:5868 [inline] lock_acquire+0x3f0/0x46c kernel/locking/lockdep.c:5825 __mutex_lock_common kernel/locking/mutex.c:614 [inline] __mutex_lock+0x14c/0x1590 kernel/locking/mutex.c:776 mutex_lock_nested+0x24/0x30 kernel/locking/mutex.c:828 elevator_change+0x188/0x420 block/elevator.c:679 elevator_set_none+0x90/0xec block/elevator.c:769 blk_mq_elv_switch_none block/blk-mq.c:5110 [inline] __blk_mq_update_nr_hw_queues block/blk-mq.c:5155 [inline] blk_mq_update_nr_hw_queues+0x3cc/0x103c block/blk-mq.c:5220 nbd_start_device+0x128/0xa28 drivers/block/nbd.c:1489 nbd_genl_connect+0xc6c/0x14dc drivers/block/nbd.c:2239 genl_family_rcv_msg_doit+0x1c0/0x28c net/netlink/genetlink.c:1114 genl_family_rcv_msg net/netlink/genetlink.c:1194 [inline] genl_rcv_msg+0x3f8/0x60c net/netlink/genetlink.c:1209 netlink_rcv_skb+0x1ac/0x360 net/netlink/af_netlink.c:2550 genl_rcv+0x38/0x54 net/netlink/genetlink.c:1218 netlink_unicast_kernel net/netlink/af_netlink.c:1318 [inline] netlink_unicast+0x420/0x6f0 net/netlink/af_netlink.c:1344 netlink_sendmsg+0x638/0xa4c net/netlink/af_netlink.c:1894 sock_sendmsg_nosec net/socket.c:727 [inline] __sock_sendmsg+0xc8/0x168 net/socket.c:742 ____sys_sendmsg+0x524/0x730 net/socket.c:2592 ___sys_sendmsg+0x124/0x1a4 net/socket.c:2646 __sys_sendmsg+0x118/0x1a4 net/socket.c:2678 __do_sys_sendmsg net/socket.c:2683 [inline] __se_sys_sendmsg net/socket.c:2681 [inline] __arm64_sys_sendmsg+0x70/0xa0 net/socket.c:2681 __invoke_syscall arch/arm64/kernel/syscall.c:35 [inline] invoke_syscall+0x70/0x260 arch/arm64/kernel/syscall.c:49 el0_svc_common.constprop.0+0xac/0x230 arch/arm64/kernel/syscall.c:132 do_el0_svc+0x40/0x58 arch/arm64/kernel/syscall.c:151 el0_svc+0x54/0x29c arch/arm64/kernel/entry-common.c:724 el0t_64_sync_handler+0xa0/0xe4 arch/arm64/kernel/entry-common.c:743 el0t_64_sync+0x198/0x19c arch/arm64/kernel/entry.S:596 -> #3 (&q->q_usage_counter(io)#33){++++}-{0:0}: lock_acquire kernel/locking/lockdep.c:5868 [inline] lock_acquire+0x3f0/0x46c kernel/locking/lockdep.c:5825 blk_alloc_queue+0x4e0/0x640 block/blk-core.c:461 blk_mq_alloc_queue+0x148/0x224 block/blk-mq.c:4429 __blk_mq_alloc_disk+0x20/0x120 block/blk-mq.c:4476 nbd_dev_add+0x3d0/0x9c0 drivers/block/nbd.c:1954 nbd_init+0x16c/0x18c drivers/block/nbd.c:2692 do_one_initcall+0x134/0xb40 init/main.c:1382 do_initcall_level init/main.c:1444 [inline] do_initcalls init/main.c:1460 [inline] do_basic_setup init/main.c:1479 [inline] kernel_init_freeable+0x5e8/0x66c init/main.c:1692 kernel_init+0x24/0x150 init/main.c:1582 ret_from_fork+0x10/0x20 arch/arm64/kernel/entry.S:860 -> #2 (fs_reclaim){+.+.}-{0:0}: lock_acquire kernel/locking/lockdep.c:5868 [inline] lock_acquire+0x3f0/0x46c kernel/locking/lockdep.c:5825 __fs_reclaim_acquire mm/page_alloc.c:4348 [inline] fs_reclaim_acquire+0x138/0x160 mm/page_alloc.c:4362 might_alloc include/linux/sched/mm.h:317 [inline] slab_pre_alloc_hook mm/slub.c:4489 [inline] slab_alloc_node mm/slub.c:4843 [inline] kmem_cache_alloc_node_noprof+0x68/0x6a0 mm/slub.c:4918 __alloc_skb+0x474/0x600 net/core/skbuff.c:702 alloc_skb_fclone include/linux/skbuff.h:1433 [inline] tcp_stream_alloc_skb+0x2c/0x450 net/ipv4/tcp.c:945 tcp_sendmsg_locked+0xd64/0x384c net/ipv4/tcp.c:1270 tcp_sendmsg+0x38/0x60 net/ipv4/tcp.c:1465 inet_sendmsg+0x90/0xe0 net/ipv4/af_inet.c:865 sock_sendmsg_nosec net/socket.c:727 [inline] __sock_sendmsg+0xc8/0x168 net/socket.c:742 sock_write_iter+0x1f4/0x330 net/socket.c:1195 new_sync_write fs/read_write.c:595 [inline] vfs_write+0x7c8/0xba4 fs/read_write.c:688 ksys_write+0x194/0x1e0 fs/read_write.c:740 __do_sys_write fs/read_write.c:751 [inline] __se_sys_write fs/read_write.c:748 [inline] __arm64_sys_write+0x6c/0xa0 fs/read_write.c:748 __invoke_syscall arch/arm64/kernel/syscall.c:35 [inline] invoke_syscall+0x70/0x260 arch/arm64/kernel/syscall.c:49 el0_svc_common.constprop.0+0xac/0x230 arch/arm64/kernel/syscall.c:132 do_el0_svc+0x40/0x58 arch/arm64/kernel/syscall.c:151 el0_svc+0x54/0x29c arch/arm64/kernel/entry-common.c:724 el0t_64_sync_handler+0xa0/0xe4 arch/arm64/kernel/entry-common.c:743 el0t_64_sync+0x198/0x19c arch/arm64/kernel/entry.S:596 -> #1 (sk_lock-AF_INET){+.+.}-{0:0}: lock_acquire kernel/locking/lockdep.c:5868 [inline] lock_acquire+0x3f0/0x46c kernel/locking/lockdep.c:5825 lock_sock_nested+0x38/0xf4 net/core/sock.c:3780 lock_sock include/net/sock.h:1709 [inline] inet_shutdown+0x50/0x318 net/ipv4/af_inet.c:919 kernel_sock_shutdown+0x54/0x84 net/socket.c:3679 nbd_mark_nsock_dead+0x100/0x530 drivers/block/nbd.c:318 recv_work+0x4a8/0x7f8 drivers/block/nbd.c:1021 process_one_work+0x810/0x1b80 kernel/workqueue.c:3276 process_scheduled_works kernel/workqueue.c:3359 [inline] worker_thread+0x42c/0xc9c kernel/workqueue.c:3440 kthread+0x2f0/0x388 kernel/kthread.c:436 ret_from_fork+0x10/0x20 arch/arm64/kernel/entry.S:860 -> #0 (&nsock->tx_lock){+.+.}-{4:4}: check_prev_add+0x114/0xca0 kernel/locking/lockdep.c:3165 check_prevs_add kernel/locking/lockdep.c:3284 [inline] validate_chain kernel/locking/lockdep.c:3908 [inline] __lock_acquire+0x13f4/0x1a5c kernel/locking/lockdep.c:5237 lock_acquire kernel/locking/lockdep.c:5868 [inline] lock_acquire+0x3f0/0x46c kernel/locking/lockdep.c:5825 __mutex_lock_common kernel/locking/mutex.c:614 [inline] __mutex_lock+0x14c/0x1590 kernel/locking/mutex.c:776 mutex_lock_nested+0x24/0x30 kernel/locking/mutex.c:828 nbd_handle_cmd drivers/block/nbd.c:1143 [inline] nbd_queue_rq+0x2e4/0xb3c drivers/block/nbd.c:1207 blk_mq_dispatch_rq_list+0x2e0/0x1778 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+0xc50/0xe60 block/blk-mq-sched.c:307 blk_mq_sched_dispatch_requests+0x7c/0x114 block/blk-mq-sched.c:329 blk_mq_run_hw_queue+0x204/0x4a4 block/blk-mq.c:2386 blk_mq_dispatch_list+0x36c/0xa90 block/blk-mq.c:2949 blk_mq_flush_plug_list block/blk-mq.c:2997 [inline] blk_mq_flush_plug_list+0xf0/0x524 block/blk-mq.c:2969 __blk_flush_plug+0x210/0x3d0 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+0x388/0x458 block/blk-core.c:649 __submit_bio_noacct_mq block/blk-core.c:722 [inline] submit_bio_noacct_nocheck+0x5bc/0xb00 block/blk-core.c:753 submit_bio_noacct+0x34c/0x1980 block/blk-core.c:884 submit_bio+0x334/0x660 block/blk-core.c:926 blk_crypto_submit_bio include/linux/blk-crypto.h:203 [inline] submit_bh_wbc+0x328/0x4a4 fs/buffer.c:2821 submit_bh fs/buffer.c:2826 [inline] block_read_full_folio+0x2a8/0x680 fs/buffer.c:2444 blkdev_read_folio+0x1c/0x28 block/fops.c:494 filemap_read_folio+0xb0/0x1fc mm/filemap.c:2501 do_read_cache_folio+0x1bc/0x364 mm/filemap.c:4101 read_cache_folio+0x44/0x6c mm/filemap.c:4133 read_mapping_folio include/linux/pagemap.h:1017 [inline] read_part_sector+0xa4/0x5f8 block/partitions/core.c:723 read_lba+0x158/0x2e8 block/partitions/efi.c:247 find_valid_gpt block/partitions/efi.c:602 [inline] efi_partition+0x1d4/0x217c block/partitions/efi.c:719 check_partition block/partitions/core.c:142 [inline] blk_add_partitions block/partitions/core.c:590 [inline] bdev_disk_changed+0x520/0x1028 block/partitions/core.c:694 blkdev_get_whole+0x144/0x1f0 block/bdev.c:764 bdev_open+0x1d4/0xa70 block/bdev.c:973 blkdev_open+0x270/0x3f0 block/fops.c:697 do_dentry_open+0x388/0x10e4 fs/open.c:949 vfs_open+0x5c/0x2fc fs/open.c:1081 do_open fs/namei.c:4677 [inline] path_openat+0x1734/0x2654 fs/namei.c:4836 do_file_open+0x18c/0x37c fs/namei.c:4865 do_sys_openat2+0xdc/0x184 fs/open.c:1366 do_sys_open fs/open.c:1372 [inline] __do_sys_openat fs/open.c:1388 [inline] __se_sys_openat fs/open.c:1383 [inline] __arm64_sys_openat+0x130/0x1d0 fs/open.c:1383 __invoke_syscall arch/arm64/kernel/syscall.c:35 [inline] invoke_syscall+0x70/0x260 arch/arm64/kernel/syscall.c:49 el0_svc_common.constprop.0+0xac/0x230 arch/arm64/kernel/syscall.c:132 do_el0_svc+0x40/0x58 arch/arm64/kernel/syscall.c:151 el0_svc+0x54/0x29c arch/arm64/kernel/entry-common.c:724 el0t_64_sync_handler+0xa0/0xe4 arch/arm64/kernel/entry-common.c:743 el0t_64_sync+0x198/0x19c arch/arm64/kernel/entry.S:596 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 udevd/21901: #0: ffff000014d44358 (&disk->open_mutex){+.+.}-{4:4}, at: bdev_open+0x2b8/0xa70 block/bdev.c:961 #1: ffff000014847a98 (set->srcu){.+.+}-{0:0}, at: blk_mq_run_hw_queue+0x1bc/0x4a4 block/blk-mq.c:2386 #2: ffff000024008180 (&cmd->lock){+.+.}-{4:4}, at: nbd_queue_rq+0xa8/0xb3c drivers/block/nbd.c:1199 stack backtrace: CPU: 1 UID: 0 PID: 21901 Comm: udevd Tainted: G L syzkaller #0 PREEMPT Tainted: [L]=SOFTLOCKUP Hardware name: linux,dummy-virt (DT) Call trace: show_stack+0x18/0x24 arch/arm64/kernel/stacktrace.c:499 (C) __dump_stack lib/dump_stack.c:94 [inline] dump_stack_lvl+0x7c/0xb0 lib/dump_stack.c:120 dump_stack+0x1c/0x28 lib/dump_stack.c:129 print_circular_bug+0x23c/0x284 kernel/locking/lockdep.c:2043 check_noncircular+0x174/0x194 kernel/locking/lockdep.c:2175 check_prev_add+0x114/0xca0 kernel/locking/lockdep.c:3165 check_prevs_add kernel/locking/lockdep.c:3284 [inline] validate_chain kernel/locking/lockdep.c:3908 [inline] __lock_acquire+0x13f4/0x1a5c kernel/locking/lockdep.c:5237 lock_acquire kernel/locking/lockdep.c:5868 [inline] lock_acquire+0x3f0/0x46c kernel/locking/lockdep.c:5825 __mutex_lock_common kernel/locking/mutex.c:614 [inline] __mutex_lock+0x14c/0x1590 kernel/locking/mutex.c:776 mutex_lock_nested+0x24/0x30 kernel/locking/mutex.c:828 nbd_handle_cmd drivers/block/nbd.c:1143 [inline] nbd_queue_rq+0x2e4/0xb3c drivers/block/nbd.c:1207 blk_mq_dispatch_rq_list+0x2e0/0x1778 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+0xc50/0xe60 block/blk-mq-sched.c:307 blk_mq_sched_dispatch_requests+0x7c/0x114 block/blk-mq-sched.c:329 blk_mq_run_hw_queue+0x204/0x4a4 block/blk-mq.c:2386 blk_mq_dispatch_list+0x36c/0xa90 block/blk-mq.c:2949 blk_mq_flush_plug_list block/blk-mq.c:2997 [inline] blk_mq_flush_plug_list+0xf0/0x524 block/blk-mq.c:2969 __blk_flush_plug+0x210/0x3d0 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+0x388/0x458 block/blk-core.c:649 __submit_bio_noacct_mq block/blk-core.c:722 [inline] submit_bio_noacct_nocheck+0x5bc/0xb00 block/blk-core.c:753 submit_bio_noacct+0x34c/0x1980 block/blk-core.c:884 submit_bio+0x334/0x660 block/blk-core.c:926 blk_crypto_submit_bio include/linux/blk-crypto.h:203 [inline] submit_bh_wbc+0x328/0x4a4 fs/buffer.c:2821 submit_bh fs/buffer.c:2826 [inline] block_read_full_folio+0x2a8/0x680 fs/buffer.c:2444 blkdev_read_folio+0x1c/0x28 block/fops.c:494 filemap_read_folio+0xb0/0x1fc mm/filemap.c:2501 do_read_cache_folio+0x1bc/0x364 mm/filemap.c:4101 read_cache_folio+0x44/0x6c mm/filemap.c:4133 read_mapping_folio include/linux/pagemap.h:1017 [inline] read_part_sector+0xa4/0x5f8 block/partitions/core.c:723 read_lba+0x158/0x2e8 block/partitions/efi.c:247 find_valid_gpt block/partitions/efi.c:602 [inline] efi_partition+0x1d4/0x217c block/partitions/efi.c:719 check_partition block/partitions/core.c:142 [inline] blk_add_partitions block/partitions/core.c:590 [inline] bdev_disk_changed+0x520/0x1028 block/partitions/core.c:694 blkdev_get_whole+0x144/0x1f0 block/bdev.c:764 bdev_open+0x1d4/0xa70 block/bdev.c:973 blkdev_open+0x270/0x3f0 block/fops.c:697 do_dentry_open+0x388/0x10e4 fs/open.c:949 vfs_open+0x5c/0x2fc fs/open.c:1081 do_open fs/namei.c:4677 [inline] path_openat+0x1734/0x2654 fs/namei.c:4836 do_file_open+0x18c/0x37c fs/namei.c:4865 do_sys_openat2+0xdc/0x184 fs/open.c:1366 do_sys_open fs/open.c:1372 [inline] __do_sys_openat fs/open.c:1388 [inline] __se_sys_openat fs/open.c:1383 [inline] __arm64_sys_openat+0x130/0x1d0 fs/open.c:1383 __invoke_syscall arch/arm64/kernel/syscall.c:35 [inline] invoke_syscall+0x70/0x260 arch/arm64/kernel/syscall.c:49 el0_svc_common.constprop.0+0xac/0x230 arch/arm64/kernel/syscall.c:132 do_el0_svc+0x40/0x58 arch/arm64/kernel/syscall.c:151 el0_svc+0x54/0x29c arch/arm64/kernel/entry-common.c:724 el0t_64_sync_handler+0xa0/0xe4 arch/arm64/kernel/entry-common.c:743 el0t_64_sync+0x198/0x19c arch/arm64/kernel/entry.S:596 block nbd0: Dead connection, failed to find a fallback block nbd0: shutting down sockets I/O error, dev nbd0, sector 0 op 0x0:(READ) flags 0x800000 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 0x800000 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 0x800000 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 0x800000 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 0x800000 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 0x800000 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 0x800000 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 0x800000 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 I/O error, dev nbd0, sector 0 op 0x0:(READ) flags 0x800000 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 0x800000 phys_seg 1 prio class 2 Buffer I/O error on dev nbd0, logical block 1, async page read nbd0: unable to read partition table