ldm_validate_partition_table(): Disk read failed.
Dev nbd1: unable to read RDB block 0
 nbd1: unable to read partition table
======================================================
WARNING: possible circular locking dependency detected
syzkaller #0 Not tainted
------------------------------------------------------
udevd/24748 is trying to acquire lock:
ffffffff8ea80c80 (fs_reclaim){+.+.}-{0:0}, at: kmem_cache_alloc_node_noprof+0x4a/0x680

but task is already holding lock:
ffffffff90165bc0 (uevent_sock_mutex){+.+.}-{4:4}, at: kobject_uevent_net_broadcast+0x27e/0x560

which lock already depends on the new lock.


the existing dependency chain (in reverse order) is:

-> #8 (uevent_sock_mutex){+.+.}-{4:4}:
       __mutex_lock+0x19d/0x1590
       kobject_uevent_net_broadcast+0x27e/0x560
       kobject_uevent_env+0x566/0x9e0
       device_add+0x544/0xb90
       device_create+0x269/0x300
       msr_device_create+0x33/0x50
       cpuhp_invoke_callback+0x448/0x860
       cpuhp_thread_fun+0x362/0x780
       smpboot_thread_fn+0x57c/0xa80
       kthread+0x389/0x470
       ret_from_fork+0x514/0xb70
       ret_from_fork_asm+0x1a/0x30

-> #7 (cpuhp_state-up){+.+.}-{0:0}:
       cpuhp_thread_fun+0x127/0x780
       smpboot_thread_fn+0x57c/0xa80
       kthread+0x389/0x470
       ret_from_fork+0x514/0xb70
       ret_from_fork_asm+0x1a/0x30

-> #6 (cpu_hotplug_lock){++++}-{0:0}:
       cpus_read_lock+0x42/0x160
       static_key_slow_inc+0x12/0x30
       nbd_genl_reconfigure+0x1301/0x1e80
       genl_family_rcv_msg_doit+0x233/0x340
       genl_rcv_msg+0x614/0x7a0
       netlink_rcv_skb+0x226/0x4a0
       genl_rcv+0x28/0x40
       netlink_unicast+0x7bb/0x940
       netlink_sendmsg+0x813/0xb40
       ____sys_sendmsg+0x9b9/0xa20
       ___sys_sendmsg+0x2a5/0x360
       __x64_sys_sendmsg+0x1bd/0x2a0
       do_syscall_64+0x174/0x580
       entry_SYSCALL_64_after_hwframe+0x77/0x7f

-> #5 (&nsock->tx_lock){+.+.}-{4:4}:
       __mutex_lock+0x19d/0x1590
       nbd_queue_rq+0x373/0x1150
       blk_mq_dispatch_rq_list+0x499/0x1990
       __blk_mq_sched_dispatch_requests+0xd36/0x1580
       blk_mq_sched_dispatch_requests+0xd7/0x190
       blk_mq_run_hw_queue+0x348/0x4f0
       blk_mq_dispatch_list+0xd11/0xe10
       blk_mq_flush_plug_list+0x45f/0x540
       __blk_flush_plug+0x3ed/0x4d0
       __submit_bio+0x465/0x560
       submit_bio_noacct_nocheck+0x2f4/0xa40
       block_read_full_folio+0x599/0x830
       filemap_read_folio+0x12c/0x3a0
       do_read_cache_folio+0x354/0x590
       read_part_sector+0xb6/0x2b0
       adfspart_check_ICS+0xb1/0x960
       bdev_disk_changed+0x82b/0x1780
       blkdev_get_whole+0x372/0x510
       bdev_open+0x324/0xd70
       blkdev_open+0x461/0x600
       do_dentry_open+0x816/0x1380
       vfs_open+0x3b/0x340
       path_openat+0x2e3b/0x3890
       do_file_open+0x23e/0x4a0
       do_sys_openat2+0x113/0x200
       __x64_sys_openat+0x138/0x170
       do_syscall_64+0x174/0x580
       entry_SYSCALL_64_after_hwframe+0x77/0x7f

-> #4 (&cmd->lock){+.+.}-{4:4}:
       __mutex_lock+0x19d/0x1590
       nbd_queue_rq+0xc1/0x1150
       blk_mq_dispatch_rq_list+0x499/0x1990
       __blk_mq_sched_dispatch_requests+0xd36/0x1580
       blk_mq_sched_dispatch_requests+0xd7/0x190
       blk_mq_run_hw_queue+0x348/0x4f0
       blk_mq_dispatch_list+0xd11/0xe10
       blk_mq_flush_plug_list+0x45f/0x540
       __blk_flush_plug+0x3ed/0x4d0
       __submit_bio+0x465/0x560
       submit_bio_noacct_nocheck+0x2f4/0xa40
       block_read_full_folio+0x599/0x830
       filemap_read_folio+0x12c/0x3a0
       do_read_cache_folio+0x354/0x590
       read_part_sector+0xb6/0x2b0
       adfspart_check_ICS+0xb1/0x960
       bdev_disk_changed+0x82b/0x1780
       blkdev_get_whole+0x372/0x510
       bdev_open+0x324/0xd70
       blkdev_open+0x461/0x600
       do_dentry_open+0x816/0x1380
       vfs_open+0x3b/0x340
       path_openat+0x2e3b/0x3890
       do_file_open+0x23e/0x4a0
       do_sys_openat2+0x113/0x200
       __x64_sys_openat+0x138/0x170
       do_syscall_64+0x174/0x580
       entry_SYSCALL_64_after_hwframe+0x77/0x7f

-> #3 (set->srcu){.+.+}-{0:0}:
       __synchronize_srcu+0xc9/0x2f0
       elevator_switch+0x1e8/0x7b0
       elevator_change+0x2fa/0x480
       elevator_set_default+0x375/0x440
       blk_register_queue+0x3f3/0x4e0
       __add_disk+0x6cb/0xe30
       add_disk_fwnode+0xfb/0x4b0
       nbd_dev_add+0x733/0xb60
       nbd_init+0x15f/0x1e0
       do_one_initcall+0x250/0x870
       do_initcall_level+0x10a/0x1a0
       do_initcalls+0x59/0xa0
       kernel_init_freeable+0x29d/0x3e0
       kernel_init+0x1d/0x1d0
       ret_from_fork+0x514/0xb70
       ret_from_fork_asm+0x1a/0x30

-> #2 (&q->elevator_lock){+.+.}-{4:4}:
       __mutex_lock+0x19d/0x1590
       elevator_change+0x1af/0x480
       elevator_set_none+0xb5/0x140
       blk_mq_update_nr_hw_queues+0x5ef/0x19f0
       nbd_start_device+0x189/0xb30
       nbd_genl_connect+0x1597/0x1c10
       genl_family_rcv_msg_doit+0x233/0x340
       genl_rcv_msg+0x614/0x7a0
       netlink_rcv_skb+0x226/0x4a0
       genl_rcv+0x28/0x40
       netlink_unicast+0x7bb/0x940
       netlink_sendmsg+0x813/0xb40
       ____sys_sendmsg+0x9b9/0xa20
       ___sys_sendmsg+0x2a5/0x360
       __x64_sys_sendmsg+0x1bd/0x2a0
       do_syscall_64+0x174/0x580
       entry_SYSCALL_64_after_hwframe+0x77/0x7f

-> #1 (&q->q_usage_counter(io)#49){++++}-{0:0}:
       blk_alloc_queue+0x544/0x690
       __blk_mq_alloc_disk+0x194/0x390
       nbd_dev_add+0x494/0xb60
       nbd_init+0x15f/0x1e0
       do_one_initcall+0x250/0x870
       do_initcall_level+0x10a/0x1a0
       do_initcalls+0x59/0xa0
       kernel_init_freeable+0x29d/0x3e0
       kernel_init+0x1d/0x1d0
       ret_from_fork+0x514/0xb70
       ret_from_fork_asm+0x1a/0x30

-> #0 (fs_reclaim){+.+.}-{0:0}:
       __lock_acquire+0x1520/0x2cd0
       lock_acquire+0x106/0x350
       fs_reclaim_acquire+0x71/0x100
       kmem_cache_alloc_node_noprof+0x4a/0x680
       __alloc_skb+0x276/0x7a0
       alloc_uevent_skb+0x7d/0x230
       kobject_uevent_net_broadcast+0x2fa/0x560
       kobject_uevent_env+0x566/0x9e0
       nbd_config_put+0x185/0x660
       nbd_release+0xfe/0x140
       bdev_release+0x571/0x690
       blkdev_release+0x15/0x20
       __fput+0x418/0xa50
       fput_close_sync+0x11f/0x240
       __x64_sys_close+0x7e/0x110
       do_syscall_64+0x174/0x580
       entry_SYSCALL_64_after_hwframe+0x77/0x7f

other info that might help us debug this:

Chain exists of:
  fs_reclaim --> cpuhp_state-up --> uevent_sock_mutex

 Possible unsafe locking scenario:

       CPU0                    CPU1
       ----                    ----
  lock(uevent_sock_mutex);
                               lock(cpuhp_state-up);
                               lock(uevent_sock_mutex);
  lock(fs_reclaim);

 *** DEADLOCK ***

3 locks held by udevd/24748:
 #0: ffff88816a20b350 (&disk->open_mutex){+.+.}-{4:4}, at: bdev_release+0x1b8/0x690
 #1: ffff88816a11f260 (&nbd->config_lock){+.+.}-{4:4}, at: refcount_dec_and_mutex_lock+0x30/0xa0
 #2: ffffffff90165bc0 (uevent_sock_mutex){+.+.}-{4:4}, at: kobject_uevent_net_broadcast+0x27e/0x560

stack backtrace:
CPU: 0 UID: 0 PID: 24748 Comm: udevd Not tainted syzkaller #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+0xe8/0x150
 print_circular_bug+0x2e1/0x300
 check_noncircular+0x12e/0x150
 __lock_acquire+0x1520/0x2cd0
 lock_acquire+0x106/0x350
 fs_reclaim_acquire+0x71/0x100
 kmem_cache_alloc_node_noprof+0x4a/0x680
 __alloc_skb+0x276/0x7a0
 alloc_uevent_skb+0x7d/0x230
 kobject_uevent_net_broadcast+0x2fa/0x560
 kobject_uevent_env+0x566/0x9e0
 nbd_config_put+0x185/0x660
 nbd_release+0xfe/0x140
 bdev_release+0x571/0x690
 blkdev_release+0x15/0x20
 __fput+0x418/0xa50
 fput_close_sync+0x11f/0x240
 __x64_sys_close+0x7e/0x110
 do_syscall_64+0x174/0x580
 entry_SYSCALL_64_after_hwframe+0x77/0x7f
RIP: 0033:0x7f74ad9170a8
Code: 48 8b 05 83 9d 0d 00 64 c7 00 16 00 00 00 83 c8 ff 48 83 c4 20 5b c3 64 8b 04 25 18 00 00 00 85 c0 75 20 b8 03 00 00 00 0f 05 <48> 3d 00 f0 ff ff 76 5b 48 8b 15 51 9d 0d 00 f7 d8 64 89 02 48 83
RSP: 002b:00007ffe9920e868 EFLAGS: 00000246 ORIG_RAX: 0000000000000003
RAX: ffffffffffffffda RBX: 00007f74adce1ae0 RCX: 00007f74ad9170a8
RDX: 0000000003938700 RSI: 000000000aba9500 RDI: 0000000000000008
RBP: 0000561d996d3780 R08: 0000000000000001 R09: 85cab173841c6c94
R10: 00000000000001b6 R11: 0000000000000246 R12: 0000000000000005
R13: 0000561d996c4aa0 R14: 0000000000000008 R15: 0000561d996b3910
 </TASK>
