======================================================
WARNING: possible circular locking dependency detected
6.16.0-rc5-syzkaller-00159-g47c84997c686-dirty #0 Not tainted
------------------------------------------------------
udevd/9199 is trying to acquire lock:
ffff888112f78470 (&nsock->tx_lock){+.+.}-{4:4}, at: nbd_queue_rq+0x257/0xf10

but task is already holding lock:
ffff888107e30178 (&cmd->lock){+.+.}-{4:4}, at: nbd_queue_rq+0xc8/0xf10

which lock already depends on the new lock.


the existing dependency chain (in reverse order) is:

-> #6 (&cmd->lock){+.+.}-{4:4}:
       lock_acquire+0x120/0x360
       __mutex_lock+0x182/0xe80
       nbd_queue_rq+0xc8/0xf10
       blk_mq_dispatch_rq_list+0x4c0/0x1900
       __blk_mq_sched_dispatch_requests+0xda4/0x1570
       blk_mq_sched_dispatch_requests+0xd7/0x190
       blk_mq_run_hw_queue+0x348/0x4f0
       blk_mq_dispatch_list+0xd0c/0xe00
       blk_mq_flush_plug_list+0x469/0x550
       __blk_flush_plug+0x3d3/0x4b0
       __submit_bio+0x2d3/0x5a0
       submit_bio_noacct_nocheck+0x4ab/0xb50
       block_read_full_folio+0x599/0x830
       filemap_read_folio+0x117/0x380
       do_read_cache_folio+0x350/0x590
       read_part_sector+0xb6/0x2b0
       adfspart_check_ICS+0xa4/0xa50
       bdev_disk_changed+0x75f/0x14b0
       blkdev_get_whole+0x380/0x510
       bdev_open+0x31e/0xd30
       blkdev_open+0x3a8/0x510
       do_dentry_open+0xdf3/0x1970
       vfs_open+0x3b/0x340
       path_openat+0x2ee5/0x3830
       do_filp_open+0x1fa/0x410
       do_sys_openat2+0x121/0x1c0
       __x64_sys_openat+0x138/0x170
       do_syscall_64+0xfa/0x3b0
       entry_SYSCALL_64_after_hwframe+0x77/0x7f

-> #5 (set->srcu){.+.+}-{0:0}:
       lock_sync+0xba/0x160
       __synchronize_srcu+0x96/0x3a0
       elevator_switch+0x12b/0x5f0
       elevator_change+0x21b/0x320
       elevator_set_default+0x144/0x210
       blk_register_queue+0x35d/0x400
       __add_disk+0x677/0xd50
       add_disk_fwnode+0xfc/0x480
       nbd_dev_add+0x70e/0xb00
       nbd_init+0x21a/0x2d0
       do_one_initcall+0x236/0x820
       do_initcall_level+0x137/0x1f0
       do_initcalls+0x69/0xd0
       kernel_init_freeable+0x3d9/0x570
       kernel_init+0x1d/0x1d0
       ret_from_fork+0x3fc/0x770
       ret_from_fork_asm+0x1a/0x30

-> #4 (&q->elevator_lock){+.+.}-{4:4}:
       lock_acquire+0x120/0x360
       __mutex_lock+0x182/0xe80
       elv_update_nr_hw_queues+0x87/0x2a0
       blk_mq_update_nr_hw_queues+0xd54/0x14c0
       nbd_start_device+0x16c/0xac0
       nbd_genl_connect+0x1250/0x1930
       genl_family_rcv_msg_doit+0x215/0x300
       genl_rcv_msg+0x60e/0x790
       netlink_rcv_skb+0x208/0x470
       genl_rcv+0x28/0x40
       netlink_unicast+0x75c/0x8e0
       netlink_sendmsg+0x805/0xb30
       __sock_sendmsg+0x21c/0x270
       ____sys_sendmsg+0x505/0x830
       ___sys_sendmsg+0x21f/0x2a0
       __x64_sys_sendmsg+0x19b/0x260
       do_syscall_64+0xfa/0x3b0
       entry_SYSCALL_64_after_hwframe+0x77/0x7f

-> #3 (&q->q_usage_counter(io)#49){++++}-{0:0}:
       lock_acquire+0x120/0x360
       blk_alloc_queue+0x538/0x620
       __blk_mq_alloc_disk+0x162/0x340
       nbd_dev_add+0x476/0xb00
       nbd_init+0x21a/0x2d0
       do_one_initcall+0x236/0x820
       do_initcall_level+0x137/0x1f0
       do_initcalls+0x69/0xd0
       kernel_init_freeable+0x3d9/0x570
       kernel_init+0x1d/0x1d0
       ret_from_fork+0x3fc/0x770
       ret_from_fork_asm+0x1a/0x30

-> #2 (fs_reclaim){+.+.}-{0:0}:
       lock_acquire+0x120/0x360
       fs_reclaim_acquire+0x72/0x100
       kmem_cache_alloc_node_noprof+0x47/0x3c0
       __alloc_skb+0x112/0x2d0
       tipc_msg_build+0x13b/0xcf0
       tipc_send_group_bcast+0x76c/0xa70
       __tipc_sendmsg+0x2d7/0x2960
       tipc_sendmsg+0x55/0x70
       __sock_sendmsg+0x21c/0x270
       ____sys_sendmsg+0x52d/0x830
       ___sys_sendmsg+0x21f/0x2a0
       __sys_sendmmsg+0x227/0x430
       __x64_sys_sendmmsg+0xa0/0xc0
       do_syscall_64+0xfa/0x3b0
       entry_SYSCALL_64_after_hwframe+0x77/0x7f

-> #1 (sk_lock-AF_TIPC){+.+.}-{0:0}:
       lock_acquire+0x120/0x360
       lock_sock_nested+0x48/0x100
       tipc_shutdown+0x62/0x4f0
       nbd_mark_nsock_dead+0x2e9/0x560
       sock_shutdown+0x15e/0x260
       nbd_config_put+0x342/0x790
       nbd_genl_connect+0x1282/0x1930
       genl_family_rcv_msg_doit+0x215/0x300
       genl_rcv_msg+0x60e/0x790
       netlink_rcv_skb+0x208/0x470
       genl_rcv+0x28/0x40
       netlink_unicast+0x75c/0x8e0
       netlink_sendmsg+0x805/0xb30
       __sock_sendmsg+0x21c/0x270
       ____sys_sendmsg+0x505/0x830
       ___sys_sendmsg+0x21f/0x2a0
       __x64_sys_sendmsg+0x19b/0x260
       do_syscall_64+0xfa/0x3b0
       entry_SYSCALL_64_after_hwframe+0x77/0x7f

-> #0 (&nsock->tx_lock){+.+.}-{4:4}:
       validate_chain+0xb9b/0x2140
       __lock_acquire+0xab9/0xd20
       lock_acquire+0x120/0x360
       __mutex_lock+0x182/0xe80
       nbd_queue_rq+0x257/0xf10
       blk_mq_dispatch_rq_list+0x4c0/0x1900
       __blk_mq_sched_dispatch_requests+0xda4/0x1570
       blk_mq_sched_dispatch_requests+0xd7/0x190
       blk_mq_run_hw_queue+0x348/0x4f0
       blk_mq_dispatch_list+0xd0c/0xe00
       blk_mq_flush_plug_list+0x469/0x550
       __blk_flush_plug+0x3d3/0x4b0
       __submit_bio+0x2d3/0x5a0
       submit_bio_noacct_nocheck+0x4ab/0xb50
       block_read_full_folio+0x599/0x830
       filemap_read_folio+0x117/0x380
       do_read_cache_folio+0x350/0x590
       read_part_sector+0xb6/0x2b0
       adfspart_check_ICS+0xa4/0xa50
       bdev_disk_changed+0x75f/0x14b0
       blkdev_get_whole+0x380/0x510
       bdev_open+0x31e/0xd30
       blkdev_open+0x3a8/0x510
       do_dentry_open+0xdf3/0x1970
       vfs_open+0x3b/0x340
       path_openat+0x2ee5/0x3830
       do_filp_open+0x1fa/0x410
       do_sys_openat2+0x121/0x1c0
       __x64_sys_openat+0x138/0x170
       do_syscall_64+0xfa/0x3b0
       entry_SYSCALL_64_after_hwframe+0x77/0x7f

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/9199:
 #0: ffff8880227b1358 (&disk->open_mutex){+.+.}-{4:4}, at: bdev_open+0xe0/0xd30
 #1: ffff8880227fa110 (set->srcu){.+.+}-{0:0}, at: blk_mq_run_hw_queue+0x31f/0x4f0
 #2: ffff888107e30178 (&cmd->lock){+.+.}-{4:4}, at: nbd_queue_rq+0xc8/0xf10

stack backtrace:
CPU: 1 UID: 0 PID: 9199 Comm: udevd Not tainted 6.16.0-rc5-syzkaller-00159-g47c84997c686-dirty #0 PREEMPT(full) 
Hardware name: QEMU Standard PC (Q35 + ICH9, 2009), BIOS 1.16.2-debian-1.16.2-1 04/01/2014
Call Trace:
 <TASK>
 dump_stack_lvl+0x189/0x250
 print_circular_bug+0x2ee/0x310
 check_noncircular+0x134/0x160
 validate_chain+0xb9b/0x2140
 __lock_acquire+0xab9/0xd20
 lock_acquire+0x120/0x360
 __mutex_lock+0x182/0xe80
 nbd_queue_rq+0x257/0xf10
 blk_mq_dispatch_rq_list+0x4c0/0x1900
 __blk_mq_sched_dispatch_requests+0xda4/0x1570
 blk_mq_sched_dispatch_requests+0xd7/0x190
 blk_mq_run_hw_queue+0x348/0x4f0
 blk_mq_dispatch_list+0xd0c/0xe00
 blk_mq_flush_plug_list+0x469/0x550
 __blk_flush_plug+0x3d3/0x4b0
 __submit_bio+0x2d3/0x5a0
 submit_bio_noacct_nocheck+0x4ab/0xb50
 block_read_full_folio+0x599/0x830
 filemap_read_folio+0x117/0x380
 do_read_cache_folio+0x350/0x590
 read_part_sector+0xb6/0x2b0
 adfspart_check_ICS+0xa4/0xa50
 bdev_disk_changed+0x75f/0x14b0
 blkdev_get_whole+0x380/0x510
 bdev_open+0x31e/0xd30
 blkdev_open+0x3a8/0x510
 do_dentry_open+0xdf3/0x1970
 vfs_open+0x3b/0x340
 path_openat+0x2ee5/0x3830
 do_filp_open+0x1fa/0x410
 do_sys_openat2+0x121/0x1c0
 __x64_sys_openat+0x138/0x170
 do_syscall_64+0xfa/0x3b0
 entry_SYSCALL_64_after_hwframe+0x77/0x7f
RIP: 0033:0x7f172b5169a4
Code: 24 20 48 8d 44 24 30 48 89 44 24 28 64 8b 04 25 18 00 00 00 85 c0 75 2c 44 89 e2 48 89 ee bf 9c ff ff ff b8 01 01 00 00 0f 05 <48> 3d 00 f0 ff ff 76 60 48 8b 15 55 a4 0d 00 f7 d8 64 89 02 48 83
RSP: 002b:00007ffcf3c2fa20 EFLAGS: 00000246 ORIG_RAX: 0000000000000101
RAX: ffffffffffffffda RBX: 0000561204c00c40 RCX: 00007f172b5169a4
RDX: 00000000000a0800 RSI: 0000561204bfb2b0 RDI: 00000000ffffff9c
RBP: 0000561204bfb2b0 R08: 0000000000000001 R09: 7fffffffffffffff
R10: 0000000000000000 R11: 0000000000000246 R12: 00000000000a0800
R13: 0000561204bee7c0 R14: 0000000000000001 R15: 0000561204bda910
 </TASK>
