======================================================
WARNING: possible circular locking dependency detected
syzkaller #0 Not tainted
------------------------------------------------------
syz.1.17101/13456 is trying to acquire lock:
ffff88811d9ee4e0 (&resv_map->rw_sema){++++}-{4:4}, at: hugetlb_fault+0x3dd/0x12c0

but task is already holding lock:
ffff888162aa0528 (&hugetlb_fault_mutex_table[i]){+.+.}-{4:4}, at: hugetlb_fault+0x3d0/0x12c0

which lock already depends on the new lock.


the existing dependency chain (in reverse order) is:

-> #9 (&hugetlb_fault_mutex_table[i]){+.+.}-{4:4}:
       __mutex_lock+0x19d/0x1550
       hugetlb_fault+0x3d0/0x12c0
       handle_mm_fault+0x1f42/0x3080
       do_user_addr_fault+0x744/0x1340
       exc_page_fault+0x6a/0xc0
       asm_exc_page_fault+0x26/0x30
       __put_user_4+0xd/0x30
       sctp_getsockopt_assoc_number+0x162/0x220
       sctp_getsockopt+0x882/0xb90
       do_sock_getsockopt+0x51d/0x7e0
       __x64_sys_getsockopt+0x1a4/0x240
       do_syscall_64+0x174/0x580
       entry_SYSCALL_64_after_hwframe+0x77/0x7f

-> #8 (sk_lock-AF_INET6){+.+.}-{0:0}:
       lock_sock_nested+0x41/0x100
       tls_sw_sendmsg+0x161/0x2860
       sock_sendmsg_nosec+0x90/0x180
       sock_write_iter+0x2de/0x3e0
       do_iter_readv_writev+0x612/0x8c0
       vfs_writev+0x343/0x990
       do_writev+0x154/0x2e0
       do_syscall_64+0x174/0x580
       entry_SYSCALL_64_after_hwframe+0x77/0x7f

-> #7 (&ctx->tx_lock){+.+.}-{4:4}:
       __mutex_lock+0x19d/0x1550
       tls_sw_sendmsg+0x13c/0x2860
       sock_sendmsg_nosec+0x90/0x180
       sock_sendmsg+0x1ca/0x2d0
       __sock_xmit+0x245/0x4f0
       nbd_disconnect+0x3ad/0x560
       nbd_disconnect_and_put+0x32/0x280
       nbd_genl_disconnect+0x4af/0x590
       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
       sock_sendmsg_nosec+0x13a/0x180
       ____sys_sendmsg+0x54e/0x850
       ___sys_sendmsg+0x2a5/0x360
       __x64_sys_sendmsg+0x1b1/0x290
       do_syscall_64+0x174/0x580
       entry_SYSCALL_64_after_hwframe+0x77/0x7f

-> #6 (&nsock->tx_lock){+.+.}-{4:4}:
       __mutex_lock+0x19d/0x1550
       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_work_fn+0x16c/0x300
       process_scheduled_works+0xa8e/0x14e0
       worker_thread+0xa47/0xfb0
       kthread+0x388/0x470
       ret_from_fork+0x514/0xb70
       ret_from_fork_asm+0x1a/0x30

-> #5 (&cmd->lock){+.+.}-{4:4}:
       __mutex_lock+0x19d/0x1550
       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_work_fn+0x16c/0x300
       process_scheduled_works+0xa8e/0x14e0
       worker_thread+0xa47/0xfb0
       kthread+0x388/0x470
       ret_from_fork+0x514/0xb70
       ret_from_fork_asm+0x1a/0x30

-> #4 (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

-> #3 (&q->elevator_lock){+.+.}-{4:4}:
       __mutex_lock+0x19d/0x1550
       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
       sock_sendmsg_nosec+0x13a/0x180
       ____sys_sendmsg+0x54e/0x850
       ___sys_sendmsg+0x2a5/0x360
       __x64_sys_sendmsg+0x1b1/0x290
       do_syscall_64+0x174/0x580
       entry_SYSCALL_64_after_hwframe+0x77/0x7f

-> #2 (&q->q_usage_counter(io)#52){++++}-{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

-> #1 (fs_reclaim){+.+.}-{0:0}:
       fs_reclaim_acquire+0x71/0x100
       prepare_alloc_pages+0x15b/0x650
       __alloc_frozen_pages_noprof+0x12f/0x380
       alloc_pages_mpol+0x212/0x380
       alloc_pages_noprof+0xac/0x2a0
       __pud_alloc+0x3a/0x460
       huge_pte_alloc+0x4f6/0x630
       hugetlb_fault+0x42e/0x12c0
       handle_mm_fault+0x1f42/0x3080
       __get_user_pages+0x1678/0x2720
       populate_vma_page_range+0x2be/0x3c0
       __mm_populate+0x25f/0x390
       vm_mmap_pgoff+0x353/0x4e0
       ksys_mmap_pgoff+0x57d/0x760
       do_syscall_64+0x174/0x580
       entry_SYSCALL_64_after_hwframe+0x77/0x7f

-> #0 (&resv_map->rw_sema){++++}-{4:4}:
       __lock_acquire+0x1520/0x2cf0
       lock_acquire+0x106/0x350
       down_read+0x4a/0x330
       hugetlb_fault+0x3dd/0x12c0
       handle_mm_fault+0x1f42/0x3080
       do_user_addr_fault+0xa4d/0x1340
       exc_page_fault+0x6a/0xc0
       asm_exc_page_fault+0x26/0x30

other info that might help us debug this:

Chain exists of:
  &resv_map->rw_sema --> sk_lock-AF_INET6 --> &hugetlb_fault_mutex_table[i]

 Possible unsafe locking scenario:

       CPU0                    CPU1
       ----                    ----
  lock(&hugetlb_fault_mutex_table[i]);
                               lock(sk_lock-AF_INET6);
                               lock(&hugetlb_fault_mutex_table[i]);
  rlock(&resv_map->rw_sema);

 *** DEADLOCK ***

2 locks held by syz.1.17101/13456:
 #0: ffff88812016a388 (vm_lock){++++}-{0:0}, at: lock_vma_under_rcu+0x1d1/0x500
 #1: ffff888162aa0528 (&hugetlb_fault_mutex_table[i]){+.+.}-{4:4}, at: hugetlb_fault+0x3d0/0x12c0

stack backtrace:
CPU: 0 UID: 0 PID: 13456 Comm: syz.1.17101 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+0x1520/0x2cf0
 lock_acquire+0x106/0x350
 down_read+0x4a/0x330
 hugetlb_fault+0x3dd/0x12c0
 handle_mm_fault+0x1f42/0x3080
 do_user_addr_fault+0xa4d/0x1340
 exc_page_fault+0x6a/0xc0
 asm_exc_page_fault+0x26/0x30
RIP: 0033:0x7fb594788240
Code: 66 0f ef c0 66 0f ef c9 66 0f ef d2 66 0f ef db 48 89 f8 48 89 f9 48 81 e1 ff 0f 00 00 48 81 f9 cf 0f 00 00 77 74 48 83 e0 f0 <66> 0f 74 00 66 0f 74 48 10 66 0f 74 50 20 66 0f 74 58 30 66 0f d7
RSP: 002b:00007fb59559ef48 EFLAGS: 00010202
RAX: 0000200000000180 RBX: 00007fb59559f014 RCX: 0000000000000180
RDX: 0000200000000180 RSI: 000020000000018f RDI: 0000200000000180
RBP: 0000000000000003 R08: 0000000000000000 R09: 0000000000000000
R10: 0000200000000180 R11: 000020000000018f R12: 0000200000000180
R13: 00007fb59559efb0 R14: 00007fb594a15fa0 R15: 0000000000000000
 </TASK>
