====================================================== WARNING: possible circular locking dependency detected syzkaller #0 Not tainted ------------------------------------------------------ syz.3.3687/18411 is trying to acquire lock: ffffffff8e643960 (fs_reclaim){+.+.}-{0:0}, at: might_alloc include/linux/sched/mm.h:318 [inline] ffffffff8e643960 (fs_reclaim){+.+.}-{0:0}, at: slab_pre_alloc_hook mm/slub.c:4721 [inline] ffffffff8e643960 (fs_reclaim){+.+.}-{0:0}, at: slab_alloc_node mm/slub.c:5044 [inline] ffffffff8e643960 (fs_reclaim){+.+.}-{0:0}, at: kmem_cache_alloc_lru_noprof+0x4a/0x6d0 mm/slub.c:5087 but task is already holding lock: ffff88802336f398 (&sb->s_type->i_mutex_key#3){++++}-{4:4}, at: inode_lock include/linux/fs.h:980 [inline] ffff88802336f398 (&sb->s_type->i_mutex_key#3){++++}-{4:4}, at: simple_start_creating+0x98/0x1e0 fs/libfs.c:2298 which lock already depends on the new lock. the existing dependency chain (in reverse order) is: -> #9 (&sb->s_type->i_mutex_key#3){++++}-{4:4}: lock_acquire+0x120/0x360 kernel/locking/lockdep.c:5868 down_write+0x96/0x1f0 kernel/locking/rwsem.c:1590 inode_lock include/linux/fs.h:980 [inline] simple_start_creating+0x98/0x1e0 fs/libfs.c:2298 start_creating+0x10f/0x180 fs/debugfs/inode.c:396 __debugfs_create_file+0x79/0x4f0 fs/debugfs/inode.c:431 debugfs_create_file_full+0x3f/0x60 fs/debugfs/inode.c:468 relay_create_buf_file kernel/relay.c:365 [inline] relay_open_buf+0x56e/0xe50 kernel/relay.c:394 relay_open+0x427/0x920 kernel/relay.c:518 do_blk_trace_setup+0x561/0x980 kernel/trace/blktrace.c:572 blk_trace_setup+0x116/0x1f0 kernel/trace/blktrace.c:614 blk_trace_ioctl+0x181/0x430 kernel/trace/blktrace.c:712 blkdev_ioctl+0x41d/0x6d0 block/ioctl.c:694 vfs_ioctl fs/ioctl.c:51 [inline] __do_sys_ioctl fs/ioctl.c:597 [inline] __se_sys_ioctl+0xfc/0x170 fs/ioctl.c:583 do_syscall_x64 arch/x86/entry/syscall_64.c:63 [inline] do_syscall_64+0xfa/0xfa0 arch/x86/entry/syscall_64.c:94 entry_SYSCALL_64_after_hwframe+0x77/0x7f -> #8 (relay_channels_mutex){+.+.}-{4:4}: lock_acquire+0x120/0x360 kernel/locking/lockdep.c:5868 __mutex_lock_common kernel/locking/mutex.c:598 [inline] __mutex_lock+0x187/0x1350 kernel/locking/mutex.c:760 relay_prepare_cpu+0x29/0x200 kernel/relay.c:443 cpuhp_invoke_callback+0x445/0x860 kernel/cpu.c:195 __cpuhp_invoke_callback_range kernel/cpu.c:968 [inline] cpuhp_invoke_callback_range kernel/cpu.c:992 [inline] cpuhp_up_callbacks kernel/cpu.c:1023 [inline] _cpu_up+0x2c9/0x580 kernel/cpu.c:1685 cpu_up+0x1d2/0x220 kernel/cpu.c:1717 cpuhp_bringup_mask+0xb2/0x1a0 kernel/cpu.c:1783 cpuhp_bringup_cpus_parallel+0x109/0x120 kernel/cpu.c:1873 bringup_nonboot_cpus+0x17/0x30 kernel/cpu.c:1887 smp_init+0x32/0x110 kernel/smp.c:1002 kernel_init_freeable+0x316/0x4b0 init/main.c:1583 kernel_init+0x1d/0x1d0 init/main.c:1481 ret_from_fork+0x4bc/0x870 arch/x86/kernel/process.c:158 ret_from_fork_asm+0x1a/0x30 arch/x86/entry/entry_64.S:245 -> #7 (cpu_hotplug_lock){++++}-{0:0}: lock_acquire+0x120/0x360 kernel/locking/lockdep.c:5868 percpu_down_read_internal include/linux/percpu-rwsem.h:53 [inline] percpu_down_read include/linux/percpu-rwsem.h:77 [inline] cpus_read_lock+0x42/0x160 kernel/cpu.c:491 static_key_slow_inc+0x12/0x30 kernel/jump_label.c:190 udp_lib_setsockopt+0x3bc/0x970 net/ipv4/udp.c:3028 udp_setsockopt+0x77/0xc0 net/ipv4/udp.c:3078 do_sock_setsockopt+0x17c/0x1b0 net/socket.c:2347 __sys_setsockopt net/socket.c:2372 [inline] __do_sys_setsockopt net/socket.c:2378 [inline] __se_sys_setsockopt net/socket.c:2375 [inline] __x64_sys_setsockopt+0x13f/0x1b0 net/socket.c:2375 do_syscall_x64 arch/x86/entry/syscall_64.c:63 [inline] do_syscall_64+0xfa/0xfa0 arch/x86/entry/syscall_64.c:94 entry_SYSCALL_64_after_hwframe+0x77/0x7f -> #6 (sk_lock-AF_INET){+.+.}-{0:0}: lock_acquire+0x120/0x360 kernel/locking/lockdep.c:5868 lock_sock_nested+0x48/0x100 net/core/sock.c:3720 lock_sock include/net/sock.h:1676 [inline] tcp_sendmsg+0x21/0x50 net/ipv4/tcp.c:1392 sock_sendmsg_nosec net/socket.c:714 [inline] __sock_sendmsg+0x19c/0x270 net/socket.c:729 sock_sendmsg+0x158/0x230 net/socket.c:752 __sock_xmit+0x1c1/0x470 drivers/block/nbd.c:574 sock_xmit drivers/block/nbd.c:602 [inline] nbd_send_cmd+0x863/0x1ba0 drivers/block/nbd.c:712 nbd_handle_cmd drivers/block/nbd.c:1174 [inline] nbd_queue_rq+0xcdb/0xf10 drivers/block/nbd.c:1204 blk_mq_dispatch_rq_list+0x4c0/0x1900 block/blk-mq.c:2129 __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+0xda4/0x1570 block/blk-mq-sched.c:307 blk_mq_sched_dispatch_requests+0xd7/0x190 block/blk-mq-sched.c:329 blk_mq_run_hw_queue+0x348/0x4f0 block/blk-mq.c:2367 blk_mq_dispatch_list+0xd0c/0xe00 include/linux/spinlock.h:-1 blk_mq_flush_plug_list+0x469/0x550 block/blk-mq.c:2976 __blk_flush_plug+0x3d3/0x4b0 block/blk-core.c:1223 blk_finish_plug block/blk-core.c:1250 [inline] __submit_bio+0x2d3/0x5a0 block/blk-core.c:649 __submit_bio_noacct_mq block/blk-core.c:722 [inline] submit_bio_noacct_nocheck+0x2fb/0xa50 block/blk-core.c:753 submit_bh fs/buffer.c:2829 [inline] __bread_slow fs/buffer.c:1272 [inline] __bread_gfp+0x216/0x3c0 fs/buffer.c:1518 sb_bread include/linux/buffer_head.h:346 [inline] udf_read_tagged+0xad/0xe00 fs/udf/misc.c:199 udf_check_anchor_block+0x99/0x550 fs/udf/super.c:1912 udf_scan_anchors fs/udf/super.c:1990 [inline] udf_load_vrs+0xa83/0xf20 fs/udf/super.c:2033 udf_fill_super+0x5ad/0x17a0 fs/udf/super.c:2201 get_tree_bdev_flags+0x40e/0x4d0 fs/super.c:1691 vfs_get_tree+0x92/0x2b0 fs/super.c:1751 fc_mount fs/namespace.c:1274 [inline] do_new_mount_fc fs/namespace.c:3726 [inline] do_new_mount+0x302/0xa10 fs/namespace.c:3802 do_mount fs/namespace.c:4125 [inline] __do_sys_mount fs/namespace.c:4324 [inline] __se_sys_mount+0x313/0x410 fs/namespace.c:4301 do_syscall_x64 arch/x86/entry/syscall_64.c:63 [inline] do_syscall_64+0xfa/0xfa0 arch/x86/entry/syscall_64.c:94 entry_SYSCALL_64_after_hwframe+0x77/0x7f -> #5 (&nsock->tx_lock){+.+.}-{4:4}: lock_acquire+0x120/0x360 kernel/locking/lockdep.c:5868 __mutex_lock_common kernel/locking/mutex.c:598 [inline] __mutex_lock+0x187/0x1350 kernel/locking/mutex.c:760 nbd_handle_cmd drivers/block/nbd.c:1140 [inline] nbd_queue_rq+0x257/0xf10 drivers/block/nbd.c:1204 blk_mq_dispatch_rq_list+0x4c0/0x1900 block/blk-mq.c:2129 __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+0xda4/0x1570 block/blk-mq-sched.c:307 blk_mq_sched_dispatch_requests+0xd7/0x190 block/blk-mq-sched.c:329 blk_mq_run_hw_queue+0x348/0x4f0 block/blk-mq.c:2367 blk_mq_dispatch_list+0xd0c/0xe00 include/linux/spinlock.h:-1 blk_mq_flush_plug_list+0x469/0x550 block/blk-mq.c:2976 __blk_flush_plug+0x3d3/0x4b0 block/blk-core.c:1223 blk_finish_plug block/blk-core.c:1250 [inline] __submit_bio+0x2d3/0x5a0 block/blk-core.c:649 __submit_bio_noacct_mq block/blk-core.c:722 [inline] submit_bio_noacct_nocheck+0x2fb/0xa50 block/blk-core.c:753 submit_bh fs/buffer.c:2829 [inline] __bread_slow fs/buffer.c:1272 [inline] __bread_gfp+0x216/0x3c0 fs/buffer.c:1518 sb_bread include/linux/buffer_head.h:346 [inline] udf_read_tagged+0xad/0xe00 fs/udf/misc.c:199 udf_check_anchor_block+0x99/0x550 fs/udf/super.c:1912 udf_scan_anchors fs/udf/super.c:1990 [inline] udf_load_vrs+0xa83/0xf20 fs/udf/super.c:2033 udf_fill_super+0x5ad/0x17a0 fs/udf/super.c:2201 get_tree_bdev_flags+0x40e/0x4d0 fs/super.c:1691 vfs_get_tree+0x92/0x2b0 fs/super.c:1751 fc_mount fs/namespace.c:1274 [inline] do_new_mount_fc fs/namespace.c:3726 [inline] do_new_mount+0x302/0xa10 fs/namespace.c:3802 do_mount fs/namespace.c:4125 [inline] __do_sys_mount fs/namespace.c:4324 [inline] __se_sys_mount+0x313/0x410 fs/namespace.c:4301 do_syscall_x64 arch/x86/entry/syscall_64.c:63 [inline] do_syscall_64+0xfa/0xfa0 arch/x86/entry/syscall_64.c:94 entry_SYSCALL_64_after_hwframe+0x77/0x7f -> #4 (&cmd->lock){+.+.}-{4:4}: lock_acquire+0x120/0x360 kernel/locking/lockdep.c:5868 __mutex_lock_common kernel/locking/mutex.c:598 [inline] __mutex_lock+0x187/0x1350 kernel/locking/mutex.c:760 nbd_queue_rq+0xc8/0xf10 drivers/block/nbd.c:1196 blk_mq_dispatch_rq_list+0x4c0/0x1900 block/blk-mq.c:2129 __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+0xda4/0x1570 block/blk-mq-sched.c:307 blk_mq_sched_dispatch_requests+0xd7/0x190 block/blk-mq-sched.c:329 blk_mq_run_hw_queue+0x348/0x4f0 block/blk-mq.c:2367 blk_mq_dispatch_list+0xd0c/0xe00 include/linux/spinlock.h:-1 blk_mq_flush_plug_list+0x469/0x550 block/blk-mq.c:2976 __blk_flush_plug+0x3d3/0x4b0 block/blk-core.c:1223 blk_finish_plug block/blk-core.c:1250 [inline] __submit_bio+0x2d3/0x5a0 block/blk-core.c:649 __submit_bio_noacct_mq block/blk-core.c:722 [inline] submit_bio_noacct_nocheck+0x2fb/0xa50 block/blk-core.c:753 submit_bh fs/buffer.c:2829 [inline] __bread_slow fs/buffer.c:1272 [inline] __bread_gfp+0x216/0x3c0 fs/buffer.c:1518 sb_bread include/linux/buffer_head.h:346 [inline] udf_check_vsd fs/udf/super.c:772 [inline] udf_load_vrs+0x365/0xf20 fs/udf/super.c:2015 udf_fill_super+0x5ad/0x17a0 fs/udf/super.c:2201 get_tree_bdev_flags+0x40e/0x4d0 fs/super.c:1691 vfs_get_tree+0x92/0x2b0 fs/super.c:1751 fc_mount fs/namespace.c:1274 [inline] do_new_mount_fc fs/namespace.c:3726 [inline] do_new_mount+0x302/0xa10 fs/namespace.c:3802 do_mount fs/namespace.c:4125 [inline] __do_sys_mount fs/namespace.c:4324 [inline] __se_sys_mount+0x313/0x410 fs/namespace.c:4301 do_syscall_x64 arch/x86/entry/syscall_64.c:63 [inline] do_syscall_64+0xfa/0xfa0 arch/x86/entry/syscall_64.c:94 entry_SYSCALL_64_after_hwframe+0x77/0x7f -> #3 (set->srcu){.+.+}-{0:0}: lock_sync+0xba/0x160 kernel/locking/lockdep.c:5916 srcu_lock_sync include/linux/srcu.h:173 [inline] __synchronize_srcu+0x96/0x3a0 kernel/rcu/srcutree.c:1429 elevator_switch+0x12b/0x640 block/elevator.c:588 elevator_change+0x315/0x4c0 block/elevator.c:691 elevator_set_default+0x186/0x260 block/elevator.c:767 blk_register_queue+0x34e/0x3f0 block/blk-sysfs.c:942 __add_disk+0x677/0xd50 block/genhd.c:528 add_disk_fwnode+0xfc/0x480 block/genhd.c:597 add_disk include/linux/blkdev.h:775 [inline] nbd_dev_add+0x717/0xae0 drivers/block/nbd.c:1981 nbd_init+0x168/0x1f0 drivers/block/nbd.c:2688 do_one_initcall+0x236/0x820 init/main.c:1281 do_initcall_level+0x104/0x190 init/main.c:1343 do_initcalls+0x59/0xa0 init/main.c:1359 kernel_init_freeable+0x334/0x4b0 init/main.c:1591 kernel_init+0x1d/0x1d0 init/main.c:1481 ret_from_fork+0x4bc/0x870 arch/x86/kernel/process.c:158 ret_from_fork_asm+0x1a/0x30 arch/x86/entry/entry_64.S:245 -> #2 (&q->elevator_lock){+.+.}-{4:4}: lock_acquire+0x120/0x360 kernel/locking/lockdep.c:5868 __mutex_lock_common kernel/locking/mutex.c:598 [inline] __mutex_lock+0x187/0x1350 kernel/locking/mutex.c:760 elevator_change+0x1e5/0x4c0 block/elevator.c:689 elevator_set_none+0x42/0xb0 block/elevator.c:782 blk_mq_elv_switch_none block/blk-mq.c:5034 [inline] __blk_mq_update_nr_hw_queues block/blk-mq.c:5077 [inline] blk_mq_update_nr_hw_queues+0x598/0x1ab0 block/blk-mq.c:5135 nbd_start_device+0x17f/0xb10 drivers/block/nbd.c:1486 nbd_genl_connect+0x135b/0x18f0 drivers/block/nbd.c:2236 genl_family_rcv_msg_doit+0x215/0x300 net/netlink/genetlink.c:1115 genl_family_rcv_msg net/netlink/genetlink.c:1195 [inline] genl_rcv_msg+0x60e/0x790 net/netlink/genetlink.c:1210 netlink_rcv_skb+0x208/0x470 net/netlink/af_netlink.c:2552 genl_rcv+0x28/0x40 net/netlink/genetlink.c:1219 netlink_unicast_kernel net/netlink/af_netlink.c:1320 [inline] netlink_unicast+0x82f/0x9e0 net/netlink/af_netlink.c:1346 netlink_sendmsg+0x805/0xb30 net/netlink/af_netlink.c:1896 sock_sendmsg_nosec net/socket.c:714 [inline] __sock_sendmsg+0x21c/0x270 net/socket.c:729 ____sys_sendmsg+0x505/0x830 net/socket.c:2617 ___sys_sendmsg+0x21f/0x2a0 net/socket.c:2671 __sys_sendmsg net/socket.c:2703 [inline] __do_sys_sendmsg net/socket.c:2708 [inline] __se_sys_sendmsg net/socket.c:2706 [inline] __x64_sys_sendmsg+0x19b/0x260 net/socket.c:2706 do_syscall_x64 arch/x86/entry/syscall_64.c:63 [inline] do_syscall_64+0xfa/0xfa0 arch/x86/entry/syscall_64.c:94 entry_SYSCALL_64_after_hwframe+0x77/0x7f -> #1 (&q->q_usage_counter(io)#49){++++}-{0:0}: lock_acquire+0x120/0x360 kernel/locking/lockdep.c:5868 blk_alloc_queue+0x538/0x620 block/blk-core.c:461 blk_mq_alloc_queue block/blk-mq.c:4401 [inline] __blk_mq_alloc_disk+0x15c/0x340 block/blk-mq.c:4448 nbd_dev_add+0x46c/0xae0 drivers/block/nbd.c:1951 nbd_init+0x168/0x1f0 drivers/block/nbd.c:2688 do_one_initcall+0x236/0x820 init/main.c:1281 do_initcall_level+0x104/0x190 init/main.c:1343 do_initcalls+0x59/0xa0 init/main.c:1359 kernel_init_freeable+0x334/0x4b0 init/main.c:1591 kernel_init+0x1d/0x1d0 init/main.c:1481 ret_from_fork+0x4bc/0x870 arch/x86/kernel/process.c:158 ret_from_fork_asm+0x1a/0x30 arch/x86/entry/entry_64.S:245 -> #0 (fs_reclaim){+.+.}-{0:0}: check_prev_add kernel/locking/lockdep.c:3165 [inline] check_prevs_add kernel/locking/lockdep.c:3284 [inline] validate_chain+0xb9b/0x2140 kernel/locking/lockdep.c:3908 __lock_acquire+0xab9/0xd20 kernel/locking/lockdep.c:5237 lock_acquire+0x120/0x360 kernel/locking/lockdep.c:5868 __fs_reclaim_acquire mm/page_alloc.c:4245 [inline] fs_reclaim_acquire+0x72/0x100 mm/page_alloc.c:4259 might_alloc include/linux/sched/mm.h:318 [inline] slab_pre_alloc_hook mm/slub.c:4721 [inline] slab_alloc_node mm/slub.c:5044 [inline] kmem_cache_alloc_lru_noprof+0x4a/0x6d0 mm/slub.c:5087 __d_alloc+0x36/0x7a0 fs/dcache.c:1690 d_alloc_parallel+0xe5/0x15e0 fs/dcache.c:2549 __lookup_slow+0x116/0x3d0 fs/namei.c:1801 simple_start_creating+0xfd/0x1e0 fs/libfs.c:2303 start_creating+0x10f/0x180 fs/debugfs/inode.c:396 debugfs_create_dir+0x28/0x420 fs/debugfs/inode.c:580 nbd_dev_dbg_init drivers/block/nbd.c:1825 [inline] nbd_start_device+0x32a/0xb10 drivers/block/nbd.c:1506 nbd_genl_connect+0x135b/0x18f0 drivers/block/nbd.c:2236 genl_family_rcv_msg_doit+0x215/0x300 net/netlink/genetlink.c:1115 genl_family_rcv_msg net/netlink/genetlink.c:1195 [inline] genl_rcv_msg+0x60e/0x790 net/netlink/genetlink.c:1210 netlink_rcv_skb+0x208/0x470 net/netlink/af_netlink.c:2552 genl_rcv+0x28/0x40 net/netlink/genetlink.c:1219 netlink_unicast_kernel net/netlink/af_netlink.c:1320 [inline] netlink_unicast+0x82f/0x9e0 net/netlink/af_netlink.c:1346 netlink_sendmsg+0x805/0xb30 net/netlink/af_netlink.c:1896 sock_sendmsg_nosec net/socket.c:714 [inline] __sock_sendmsg+0x21c/0x270 net/socket.c:729 ____sys_sendmsg+0x505/0x830 net/socket.c:2617 ___sys_sendmsg+0x21f/0x2a0 net/socket.c:2671 __sys_sendmsg net/socket.c:2703 [inline] __do_sys_sendmsg net/socket.c:2708 [inline] __se_sys_sendmsg net/socket.c:2706 [inline] __x64_sys_sendmsg+0x19b/0x260 net/socket.c:2706 do_syscall_x64 arch/x86/entry/syscall_64.c:63 [inline] do_syscall_64+0xfa/0xfa0 arch/x86/entry/syscall_64.c:94 entry_SYSCALL_64_after_hwframe+0x77/0x7f other info that might help us debug this: Chain exists of: fs_reclaim --> relay_channels_mutex --> &sb->s_type->i_mutex_key#3 Possible unsafe locking scenario: CPU0 CPU1 ---- ---- lock(&sb->s_type->i_mutex_key#3); lock(relay_channels_mutex); lock(&sb->s_type->i_mutex_key#3); lock(fs_reclaim); *** DEADLOCK *** 4 locks held by syz.3.3687/18411: #0: ffffffff8f9ba850 (cb_lock){++++}-{4:4}, at: genl_rcv+0x19/0x40 net/netlink/genetlink.c:1218 #1: ffffffff8f9ba668 (genl_mutex){+.+.}-{4:4}, at: genl_lock net/netlink/genetlink.c:35 [inline] #1: ffffffff8f9ba668 (genl_mutex){+.+.}-{4:4}, at: genl_op_lock net/netlink/genetlink.c:60 [inline] #1: ffffffff8f9ba668 (genl_mutex){+.+.}-{4:4}, at: genl_rcv_msg+0x10d/0x790 net/netlink/genetlink.c:1209 #2: ffff88802523f270 (&nbd->config_lock){+.+.}-{4:4}, at: nbd_start_device+0x189/0xb10 drivers/block/nbd.c:1487 #3: ffff88802336f398 (&sb->s_type->i_mutex_key#3){++++}-{4:4}, at: inode_lock include/linux/fs.h:980 [inline] #3: ffff88802336f398 (&sb->s_type->i_mutex_key#3){++++}-{4:4}, at: simple_start_creating+0x98/0x1e0 fs/libfs.c:2298 stack backtrace: CPU: 1 UID: 0 PID: 18411 Comm: syz.3.3687 Not tainted syzkaller #0 PREEMPT(full) Hardware name: Google Google Compute Engine/Google Compute Engine, BIOS Google 08/18/2025 Call Trace: dump_stack_lvl+0x189/0x250 lib/dump_stack.c:120 print_circular_bug+0x2ee/0x310 kernel/locking/lockdep.c:2043 check_noncircular+0x134/0x160 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+0xb9b/0x2140 kernel/locking/lockdep.c:3908 __lock_acquire+0xab9/0xd20 kernel/locking/lockdep.c:5237 lock_acquire+0x120/0x360 kernel/locking/lockdep.c:5868 __fs_reclaim_acquire mm/page_alloc.c:4245 [inline] fs_reclaim_acquire+0x72/0x100 mm/page_alloc.c:4259 might_alloc include/linux/sched/mm.h:318 [inline] slab_pre_alloc_hook mm/slub.c:4721 [inline] slab_alloc_node mm/slub.c:5044 [inline] kmem_cache_alloc_lru_noprof+0x4a/0x6d0 mm/slub.c:5087 __d_alloc+0x36/0x7a0 fs/dcache.c:1690 d_alloc_parallel+0xe5/0x15e0 fs/dcache.c:2549 __lookup_slow+0x116/0x3d0 fs/namei.c:1801 simple_start_creating+0xfd/0x1e0 fs/libfs.c:2303 start_creating+0x10f/0x180 fs/debugfs/inode.c:396 debugfs_create_dir+0x28/0x420 fs/debugfs/inode.c:580 nbd_dev_dbg_init drivers/block/nbd.c:1825 [inline] nbd_start_device+0x32a/0xb10 drivers/block/nbd.c:1506 nbd_genl_connect+0x135b/0x18f0 drivers/block/nbd.c:2236 genl_family_rcv_msg_doit+0x215/0x300 net/netlink/genetlink.c:1115 genl_family_rcv_msg net/netlink/genetlink.c:1195 [inline] genl_rcv_msg+0x60e/0x790 net/netlink/genetlink.c:1210 netlink_rcv_skb+0x208/0x470 net/netlink/af_netlink.c:2552 genl_rcv+0x28/0x40 net/netlink/genetlink.c:1219 netlink_unicast_kernel net/netlink/af_netlink.c:1320 [inline] netlink_unicast+0x82f/0x9e0 net/netlink/af_netlink.c:1346 netlink_sendmsg+0x805/0xb30 net/netlink/af_netlink.c:1896 sock_sendmsg_nosec net/socket.c:714 [inline] __sock_sendmsg+0x21c/0x270 net/socket.c:729 ____sys_sendmsg+0x505/0x830 net/socket.c:2617 ___sys_sendmsg+0x21f/0x2a0 net/socket.c:2671 __sys_sendmsg net/socket.c:2703 [inline] __do_sys_sendmsg net/socket.c:2708 [inline] __se_sys_sendmsg net/socket.c:2706 [inline] __x64_sys_sendmsg+0x19b/0x260 net/socket.c:2706 do_syscall_x64 arch/x86/entry/syscall_64.c:63 [inline] do_syscall_64+0xfa/0xfa0 arch/x86/entry/syscall_64.c:94 entry_SYSCALL_64_after_hwframe+0x77/0x7f RIP: 0033:0x7f7d8178eba9 Code: ff ff c3 66 2e 0f 1f 84 00 00 00 00 00 0f 1f 40 00 48 89 f8 48 89 f7 48 89 d6 48 89 ca 4d 89 c2 4d 89 c8 4c 8b 4c 24 08 0f 05 <48> 3d 01 f0 ff ff 73 01 c3 48 c7 c1 a8 ff ff ff f7 d8 64 89 01 48 RSP: 002b:00007f7d82663038 EFLAGS: 00000246 ORIG_RAX: 000000000000002e RAX: ffffffffffffffda RBX: 00007f7d819d5fa0 RCX: 00007f7d8178eba9 RDX: 0000000020000000 RSI: 0000200000001ac0 RDI: 0000000000000004 RBP: 00007f7d81811e19 R08: 0000000000000000 R09: 0000000000000000 R10: 0000000000000000 R11: 0000000000000246 R12: 0000000000000000 R13: 00007f7d819d6038 R14: 00007f7d819d5fa0 R15: 00007ffdff1a8888 nbd0: detected capacity change from 0 to 127