====================================================== WARNING: possible circular locking dependency detected syzkaller #0 Not tainted ------------------------------------------------------ syz.2.2536/16268 is trying to acquire lock: ffff88801cec4a10 (&root->kernfs_iattr_rwsem){++++}-{4:4}, at: kernfs_unlink_sibling+0x6d/0x240 fs/kernfs/dir.c:443 but task is already holding lock: ffff88801cec4980 (&root->kernfs_rwsem){++++}-{4:4}, at: kernfs_rename_ns+0xb4/0x9e0 fs/kernfs/dir.c:1837 which lock already depends on the new lock. the existing dependency chain (in reverse order) is: -> #10 (&root->kernfs_rwsem){++++}-{4:4}: down_write+0x91/0x200 kernel/locking/rwsem.c:1631 kernfs_add_one+0x41/0x510 fs/kernfs/dir.c:833 kernfs_create_dir_ns+0x18c/0x220 fs/kernfs/dir.c:1143 internal_create_group+0x440/0x1180 fs/sysfs/group.c:176 cpuhp_invoke_callback+0x434/0x810 kernel/cpu.c:194 cpuhp_issue_call+0x3f0/0x750 kernel/cpu.c:-1 __cpuhp_setup_state_cpuslocked+0x3f4/0x6f0 kernel/cpu.c:2507 __cpuhp_setup_state+0x3f/0x60 kernel/cpu.c:2536 do_one_initcall+0x250/0x870 init/main.c:1419 do_initcall_level+0x10a/0x1a0 init/main.c:1481 do_initcalls+0x59/0xa0 init/main.c:1497 kernel_init_freeable+0x29d/0x3e0 init/main.c:1732 kernel_init+0x22/0x1d0 init/main.c:1622 ret_from_fork+0x514/0xb70 arch/x86/kernel/process.c:158 ret_from_fork_asm+0x1a/0x30 arch/x86/entry/entry_64.S:245 -> #9 (cpuhp_state_mutex){+.+.}-{4:4}: -> #8 (cpu_hotplug_lock){++++}-{0:0}: percpu_down_read_internal include/linux/percpu-rwsem.h:53 [inline] percpu_down_read include/linux/percpu-rwsem.h:77 [inline] cpus_read_lock+0x3d/0x160 kernel/cpu.c:490 static_key_slow_inc+0x12/0x30 kernel/jump_label.c:190 fl_create net/ipv6/ip6_flowlabel.c:451 [inline] ipv6_flowlabel_get net/ipv6/ip6_flowlabel.c:655 [inline] ipv6_flowlabel_opt+0x1cac/0x2b10 net/ipv6/ip6_flowlabel.c:770 do_ipv6_setsockopt+0x9cb/0x2960 net/ipv6/ipv6_sockglue.c:843 ipv6_setsockopt+0x59/0x170 net/ipv6/ipv6_sockglue.c:880 rawv6_setsockopt+0x276/0x5e0 net/ipv6/raw.c:1048 do_sock_setsockopt+0x17c/0x1b0 net/socket.c:2399 __sys_setsockopt net/socket.c:2424 [inline] __do_sys_setsockopt net/socket.c:2430 [inline] __se_sys_setsockopt net/socket.c:2427 [inline] __x64_sys_setsockopt+0x13d/0x1b0 net/socket.c:2427 do_syscall_x64 arch/x86/entry/syscall_64.c:61 [inline] do_syscall_64+0x166/0x520 arch/x86/entry/syscall_64.c:84 entry_SYSCALL_64_after_hwframe+0x77/0x7f -> #7 (sk_lock-AF_INET6){+.+.}-{0:0}: lock_sock_nested+0x41/0x100 net/core/sock.c:3908 lock_sock include/net/sock.h:1717 [inline] inet_shutdown+0x6a/0x390 net/ipv4/af_inet.c:911 nbd_mark_nsock_dead+0x2cb/0x550 drivers/block/nbd.c:319 sock_shutdown+0x15e/0x260 drivers/block/nbd.c:420 nbd_clear_sock+0x24/0x170 drivers/block/nbd.c:1463 nbd_config_put+0x477/0x7e0 drivers/block/nbd.c:1492 nbd_genl_connect+0x19b8/0x1cd0 drivers/block/nbd.c:2319 genl_family_rcv_msg_doit+0x233/0x340 net/netlink/genetlink.c:1114 genl_family_rcv_msg net/netlink/genetlink.c:1194 [inline] genl_rcv_msg+0x614/0x7a0 net/netlink/genetlink.c:1209 netlink_rcv_skb+0x226/0x4a0 net/netlink/af_netlink.c:2584 genl_rcv+0x28/0x40 net/netlink/genetlink.c:1218 netlink_unicast_kernel net/netlink/af_netlink.c:1335 [inline] netlink_unicast+0x8ef/0xa80 net/netlink/af_netlink.c:1361 netlink_sendmsg+0x7f0/0xb20 net/netlink/af_netlink.c:1920 sock_sendmsg_nosec+0x14e/0x190 net/socket.c:800 __sock_sendmsg net/socket.c:818 [inline] ____sys_sendmsg+0x54e/0x850 net/socket.c:2715 ___sys_sendmsg+0x2a5/0x360 net/socket.c:2769 __sys_sendmsg net/socket.c:2801 [inline] __do_sys_sendmsg net/socket.c:2806 [inline] __se_sys_sendmsg net/socket.c:2804 [inline] __x64_sys_sendmsg+0x1b1/0x290 net/socket.c:2804 do_syscall_x64 arch/x86/entry/syscall_64.c:61 [inline] do_syscall_64+0x166/0x520 arch/x86/entry/syscall_64.c:84 entry_SYSCALL_64_after_hwframe+0x77/0x7f -> #6 (&nsock->tx_lock){+.+.}-{4:4}: __mutex_lock_common kernel/locking/mutex.c:646 [inline] __mutex_lock+0x197/0x15a0 kernel/locking/mutex.c:821 nbd_handle_cmd drivers/block/nbd.c:1143 [inline] nbd_queue_rq+0x373/0xff0 drivers/block/nbd.c:1207 blk_mq_dispatch_rq_list+0x499/0x1990 block/blk-mq.c:2131 __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+0xd36/0x1580 block/blk-mq-sched.c:307 blk_mq_sched_dispatch_requests+0xd7/0x190 block/blk-mq-sched.c:329 blk_mq_run_work_fn+0x167/0x2f0 block/blk-mq.c:2546 process_one_work kernel/workqueue.c:3495 [inline] process_scheduled_works+0xc3d/0x1630 kernel/workqueue.c:3578 worker_thread+0xa47/0xfb0 kernel/workqueue.c:3659 kthread+0x38b/0x480 kernel/kthread.c:436 ret_from_fork+0x514/0xb70 arch/x86/kernel/process.c:158 ret_from_fork_asm+0x1a/0x30 arch/x86/entry/entry_64.S:245 -> #5 (&cmd->lock){+.+.}-{4:4}: __mutex_lock_common kernel/locking/mutex.c:646 [inline] __mutex_lock+0x197/0x15a0 kernel/locking/mutex.c:821 nbd_queue_rq+0xc1/0xff0 drivers/block/nbd.c:1199 blk_mq_dispatch_rq_list+0x499/0x1990 block/blk-mq.c:2131 __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+0xd36/0x1580 block/blk-mq-sched.c:307 blk_mq_sched_dispatch_requests+0xd7/0x190 block/blk-mq-sched.c:329 blk_mq_run_work_fn+0x167/0x2f0 block/blk-mq.c:2546 process_one_work kernel/workqueue.c:3495 [inline] process_scheduled_works+0xc3d/0x1630 kernel/workqueue.c:3578 worker_thread+0xa47/0xfb0 kernel/workqueue.c:3659 kthread+0x38b/0x480 kernel/kthread.c:436 ret_from_fork+0x514/0xb70 arch/x86/kernel/process.c:158 ret_from_fork_asm+0x1a/0x30 arch/x86/entry/entry_64.S:245 -> #4 (set->srcu){.+.+}-{0:0}: srcu_lock_sync include/linux/srcu.h:225 [inline] __synchronize_srcu+0xca/0x2f0 kernel/rcu/srcutree.c:1662 elevator_switch+0x1e8/0x7b0 block/elevator.c:576 elevator_change+0x2fa/0x480 block/elevator.c:681 elevator_set_default+0x375/0x440 block/elevator.c:754 blk_register_queue+0x404/0x4f0 block/blk-sysfs.c:992 __add_disk+0x6b8/0xdb0 block/genhd.c:531 add_disk_fwnode+0x100/0x3a0 block/genhd.c:600 add_disk include/linux/blkdev.h:801 [inline] nbd_dev_add+0x733/0xb60 drivers/block/nbd.c:2026 nbd_init+0x168/0x1f0 drivers/block/nbd.c:2743 do_one_initcall+0x250/0x870 init/main.c:1419 do_initcall_level+0x10a/0x1a0 init/main.c:1481 do_initcalls+0x59/0xa0 init/main.c:1497 kernel_init_freeable+0x29d/0x3e0 init/main.c:1732 kernel_init+0x22/0x1d0 init/main.c:1622 ret_from_fork+0x514/0xb70 arch/x86/kernel/process.c:158 ret_from_fork_asm+0x1a/0x30 arch/x86/entry/entry_64.S:245 -> #3 (&q->elevator_lock){+.+.}-{4:4}: __mutex_lock_common kernel/locking/mutex.c:646 [inline] __mutex_lock+0x197/0x15a0 kernel/locking/mutex.c:821 elevator_change+0x1af/0x480 block/elevator.c:679 elevator_set_none+0xb5/0x140 block/elevator.c:769 blk_mq_elv_switch_none block/blk-mq.c:5114 [inline] __blk_mq_update_nr_hw_queues block/blk-mq.c:5159 [inline] blk_mq_update_nr_hw_queues+0x5ef/0x19e0 block/blk-mq.c:5224 nbd_start_device+0x189/0xb30 drivers/block/nbd.c:1530 nbd_genl_connect+0x167d/0x1cd0 drivers/block/nbd.c:2310 genl_family_rcv_msg_doit+0x233/0x340 net/netlink/genetlink.c:1114 genl_family_rcv_msg net/netlink/genetlink.c:1194 [inline] genl_rcv_msg+0x614/0x7a0 net/netlink/genetlink.c:1209 netlink_rcv_skb+0x226/0x4a0 net/netlink/af_netlink.c:2584 genl_rcv+0x28/0x40 net/netlink/genetlink.c:1218 netlink_unicast_kernel net/netlink/af_netlink.c:1335 [inline] netlink_unicast+0x8ef/0xa80 net/netlink/af_netlink.c:1361 netlink_sendmsg+0x7f0/0xb20 net/netlink/af_netlink.c:1920 sock_sendmsg_nosec+0x14e/0x190 net/socket.c:800 __sock_sendmsg net/socket.c:818 [inline] ____sys_sendmsg+0x54e/0x850 net/socket.c:2715 ___sys_sendmsg+0x2a5/0x360 net/socket.c:2769 __sys_sendmsg net/socket.c:2801 [inline] __do_sys_sendmsg net/socket.c:2806 [inline] __se_sys_sendmsg net/socket.c:2804 [inline] __x64_sys_sendmsg+0x1b1/0x290 net/socket.c:2804 do_syscall_x64 arch/x86/entry/syscall_64.c:61 [inline] do_syscall_64+0x166/0x520 arch/x86/entry/syscall_64.c:84 entry_SYSCALL_64_after_hwframe+0x77/0x7f -> #2 (&q->q_usage_counter(io)#50){++++}-{0:0}: blk_alloc_queue+0x544/0x690 block/blk-core.c:505 blk_mq_alloc_queue block/blk-mq.c:4439 [inline] __blk_mq_alloc_disk+0x194/0x390 block/blk-mq.c:4486 nbd_dev_add+0x494/0xb60 drivers/block/nbd.c:1996 nbd_init+0x168/0x1f0 drivers/block/nbd.c:2743 do_one_initcall+0x250/0x870 init/main.c:1419 do_initcall_level+0x10a/0x1a0 init/main.c:1481 do_initcalls+0x59/0xa0 init/main.c:1497 kernel_init_freeable+0x29d/0x3e0 init/main.c:1732 kernel_init+0x22/0x1d0 init/main.c:1622 ret_from_fork+0x514/0xb70 arch/x86/kernel/process.c:158 ret_from_fork_asm+0x1a/0x30 arch/x86/entry/entry_64.S:245 -> #1 (fs_reclaim){+.+.}-{0:0}: __fs_reclaim_acquire mm/page_alloc.c:4360 [inline] fs_reclaim_acquire+0x71/0x100 mm/page_alloc.c:4374 might_alloc include/linux/sched/mm.h:316 [inline] slab_pre_alloc_hook mm/slub.c:4673 [inline] slab_alloc_node mm/slub.c:5011 [inline] kmem_cache_alloc_noprof+0x5f/0x600 mm/slub.c:5047 __kernfs_iattrs+0xdd/0x380 fs/kernfs/inode.c:36 kernfs_iattrs fs/kernfs/inode.c:60 [inline] __kernfs_setattr fs/kernfs/inode.c:73 [inline] kernfs_iop_setattr+0xe6/0x3f0 fs/kernfs/inode.c:127 notify_change+0xbba/0xea0 fs/attr.c:556 do_truncate+0x1c2/0x250 fs/open.c:68 handle_truncate fs/namei.c:4300 [inline] do_open fs/namei.c:4849 [inline] path_openat+0x18a6/0x20f0 fs/namei.c:5010 do_file_open+0x23e/0x4a0 fs/namei.c:5039 do_sys_openat2+0x115/0x200 fs/open.c:1442 do_sys_open fs/open.c:1448 [inline] __do_sys_openat fs/open.c:1464 [inline] __se_sys_openat fs/open.c:1459 [inline] __x64_sys_openat+0x138/0x170 fs/open.c:1459 do_syscall_x64 arch/x86/entry/syscall_64.c:61 [inline] do_syscall_64+0x166/0x520 arch/x86/entry/syscall_64.c:84 entry_SYSCALL_64_after_hwframe+0x77/0x7f -> #0 (&root->kernfs_iattr_rwsem){++++}-{4:4}: check_prev_add kernel/locking/lockdep.c:3209 [inline] check_prevs_add kernel/locking/lockdep.c:3328 [inline] validate_chain kernel/locking/lockdep.c:3952 [inline] __lock_acquire+0x164c/0x2de0 kernel/locking/lockdep.c:5288 lock_acquire+0x115/0x350 kernel/locking/lockdep.c:5942 down_write+0x91/0x200 kernel/locking/rwsem.c:1631 kernfs_unlink_sibling+0x6d/0x240 fs/kernfs/dir.c:443 kernfs_rename_ns+0x575/0x9e0 fs/kernfs/dir.c:1878 sysfs_rename_link_ns+0x16e/0x1b0 fs/sysfs/symlink.c:193 device_rename+0x110/0x210 drivers/base/core.c:4628 ib_device_rename+0x2ea/0x750 drivers/infiniband/core/device.c:406 nldev_set_doit+0x3c5/0x5f0 drivers/infiniband/core/nldev.c:1217 rdma_nl_rcv_msg drivers/infiniband/core/netlink.c:-1 [inline] rdma_nl_rcv_skb drivers/infiniband/core/netlink.c:239 [inline] rdma_nl_rcv+0x6ef/0xa40 drivers/infiniband/core/netlink.c:259 netlink_unicast_kernel net/netlink/af_netlink.c:1335 [inline] netlink_unicast+0x8ef/0xa80 net/netlink/af_netlink.c:1361 netlink_sendmsg+0x7f0/0xb20 net/netlink/af_netlink.c:1920 sock_sendmsg_nosec+0x14e/0x190 net/socket.c:800 __sock_sendmsg net/socket.c:818 [inline] ____sys_sendmsg+0x54e/0x850 net/socket.c:2715 ___sys_sendmsg+0x2a5/0x360 net/socket.c:2769 __sys_sendmsg net/socket.c:2801 [inline] __do_sys_sendmsg net/socket.c:2806 [inline] __se_sys_sendmsg net/socket.c:2804 [inline] __x64_sys_sendmsg+0x1b1/0x290 net/socket.c:2804 do_syscall_x64 arch/x86/entry/syscall_64.c:61 [inline] do_syscall_64+0x166/0x520 arch/x86/entry/syscall_64.c:84 entry_SYSCALL_64_after_hwframe+0x77/0x7f other info that might help us debug this: Chain exists of: &root->kernfs_iattr_rwsem --> cpuhp_state_mutex --> &root->kernfs_rwsem Possible unsafe locking scenario: CPU0 CPU1 ---- ---- lock(&root->kernfs_rwsem); lock(cpuhp_state_mutex); lock(&root->kernfs_rwsem); lock(&root->kernfs_iattr_rwsem); *** DEADLOCK *** locks held by syz.2.2536/16268: 3, last CPU#0: #0: ffffffff9c03d728 (&rdma_nl_types[idx].sem){.+.+}-{4:4}, at: rdma_nl_rcv_msg drivers/infiniband/core/netlink.c:164 [inline] #0: ffffffff9c03d728 (&rdma_nl_types[idx].sem){.+.+}-{4:4}, at: rdma_nl_rcv_skb drivers/infiniband/core/netlink.c:239 [inline] #0: ffffffff9c03d728 (&rdma_nl_types[idx].sem){.+.+}-{4:4}, at: rdma_nl_rcv+0x33d/0xa40 drivers/infiniband/core/netlink.c:259 #1: ffffffff911df1e8 (devices_rwsem){++++}-{4:4}, at: ib_device_rename+0x88/0x750 drivers/infiniband/core/device.c:395 #2: ffff88801cec4980 (&root->kernfs_rwsem){++++}-{4:4}, at: kernfs_rename_ns+0xb4/0x9e0 fs/kernfs/dir.c:1837 stack backtrace: CPU: 0 UID: 0 PID: 16268 Comm: syz.2.2536 Not tainted syzkaller #0 PREEMPT(full) Hardware name: Google Google Compute Engine/Google Compute Engine, BIOS Google 10/07/2026 Call Trace: dump_stack_lvl+0xe8/0x150 lib/dump_stack.c:120 print_circular_bug+0x2e2/0x300 kernel/locking/lockdep.c:2087 check_noncircular+0x12f/0x150 kernel/locking/lockdep.c:2219 check_prev_add kernel/locking/lockdep.c:3209 [inline] check_prevs_add kernel/locking/lockdep.c:3328 [inline] validate_chain kernel/locking/lockdep.c:3952 [inline] __lock_acquire+0x164c/0x2de0 kernel/locking/lockdep.c:5288 lock_acquire+0x115/0x350 kernel/locking/lockdep.c:5942 down_write+0x91/0x200 kernel/locking/rwsem.c:1631 kernfs_unlink_sibling+0x6d/0x240 fs/kernfs/dir.c:443 kernfs_rename_ns+0x575/0x9e0 fs/kernfs/dir.c:1878 sysfs_rename_link_ns+0x16e/0x1b0 fs/sysfs/symlink.c:193 device_rename+0x110/0x210 drivers/base/core.c:4628 ib_device_rename+0x2ea/0x750 drivers/infiniband/core/device.c:406 nldev_set_doit+0x3c5/0x5f0 drivers/infiniband/core/nldev.c:1217 rdma_nl_rcv_msg drivers/infiniband/core/netlink.c:-1 [inline] rdma_nl_rcv_skb drivers/infiniband/core/netlink.c:239 [inline] rdma_nl_rcv+0x6ef/0xa40 drivers/infiniband/core/netlink.c:259 netlink_unicast_kernel net/netlink/af_netlink.c:1335 [inline] netlink_unicast+0x8ef/0xa80 net/netlink/af_netlink.c:1361 netlink_sendmsg+0x7f0/0xb20 net/netlink/af_netlink.c:1920 sock_sendmsg_nosec+0x14e/0x190 net/socket.c:800 __sock_sendmsg net/socket.c:818 [inline] ____sys_sendmsg+0x54e/0x850 net/socket.c:2715 ___sys_sendmsg+0x2a5/0x360 net/socket.c:2769 __sys_sendmsg net/socket.c:2801 [inline] __do_sys_sendmsg net/socket.c:2806 [inline] __se_sys_sendmsg net/socket.c:2804 [inline] __x64_sys_sendmsg+0x1b1/0x290 net/socket.c:2804 do_syscall_x64 arch/x86/entry/syscall_64.c:61 [inline] do_syscall_64+0x166/0x520 arch/x86/entry/syscall_64.c:84 entry_SYSCALL_64_after_hwframe+0x77/0x7f RIP: 0033:0x7fc97c59fb19 Code: ff c3 66 2e 0f 1f 84 00 00 00 00 00 0f 1f 44 00 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 e8 ff ff ff f7 d8 64 89 01 48 RSP: 002b:00007fc97d441028 EFLAGS: 00000246 ORIG_RAX: 000000000000002e RAX: ffffffffffffffda RBX: 00007fc97c825fa0 RCX: 00007fc97c59fb19 RDX: 00000000000488c0 RSI: 0000200000000780 RDI: 0000000000000003 RBP: 00007fc97c637b70 R08: 0000000000000000 R09: 0000000000000000 R10: 0000000000000000 R11: 0000000000000246 R12: 0000000000000000 R13: 00007fc97c826038 R14: 00007fc97c825fa0 R15: 00007ffe506bd548 smbdirect: ib_dev[rxe0] renamed to [s]