======================================================
WARNING: possible circular locking dependency detected
syzkaller #0 Not tainted
------------------------------------------------------
syz.0.3042/16897 is trying to acquire lock:
ffffffff8fe95920 (fs_reclaim){+.+.}-{0:0}, at: prepare_alloc_pages+0x149/0x600

but task is already holding lock:
ffff88811299c508 (vm_lock){++++}-{0:0}, at: lock_vma_under_rcu+0x1d1/0x500

which lock already depends on the new lock.


the existing dependency chain (in reverse order) is:

-> #11 (vm_lock){++++}-{0:0}:
       __vma_start_exclude_readers+0x283/0x930
       __vma_start_write+0xdc/0x290
       mprotect_fixup+0x657/0xad0
       setup_arg_pages+0x658/0xbd0
       load_elf_binary+0xc6c/0x28d0
       bprm_execve+0x930/0x1590
       kernel_execve+0x8c3/0x9c0
       try_to_run_init_process+0x13/0x60
       kernel_init+0xb2/0x1d0
       ret_from_fork+0x514/0xb70
       ret_from_fork_asm+0x1a/0x30

-> #10 (&mm->mmap_lock){++++}-{4:4}:
       __might_fault+0xcb/0x130
       _copy_from_user+0x28/0xb0
       memdup_user+0x5e/0xd0
       strndup_user+0x68/0xd0
       perf_ioctl+0x7ba/0x20d0
       __se_sys_ioctl+0xfc/0x170
       do_syscall_64+0x166/0x520
       entry_SYSCALL_64_after_hwframe+0x77/0x7f

-> #9 (&cpuctx_mutex){+.+.}-{4:4}:
       __mutex_lock+0x19d/0x1550
       perf_event_init_cpu+0x66b/0x7a0
       perf_event_init+0x16c/0x220
       start_kernel+0x20b/0x3e0
       x86_64_start_reservations+0x24/0x30
       x86_64_start_kernel+0x137/0x1b0
       common_startup_64+0x13e/0x157

-> #8 (pmus_lock){+.+.}-{4:4}:
       __mutex_lock+0x19d/0x1550
       perf_event_init_cpu+0x1d1/0x7a0
       cpuhp_invoke_callback+0x434/0x810
       cpuhp_thread_fun+0x362/0x780
       smpboot_thread_fn+0x565/0xa70
       kthread+0x38b/0x480
       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+0x565/0xa70
       kthread+0x38b/0x480
       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_reconnect_sock_cb+0x69a/0xbb0
       nbd_genl_foreach_sock+0x265/0x450
       nbd_genl_reconfigure+0xbbb/0x1040
       genl_family_rcv_msg_doit+0x233/0x340
       genl_rcv_msg+0x614/0x7a0
       netlink_rcv_skb+0x226/0x4a0
       genl_rcv+0x28/0x40
       netlink_unicast+0x7bd/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+0x166/0x520
       entry_SYSCALL_64_after_hwframe+0x77/0x7f

-> #5 (&nsock->tx_lock){+.+.}-{4:4}:
       __mutex_lock+0x19d/0x1550
       nbd_queue_rq+0x373/0xff0
       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+0xc3d/0x1630
       worker_thread+0xa47/0xfb0
       kthread+0x38b/0x480
       ret_from_fork+0x514/0xb70
       ret_from_fork_asm+0x1a/0x30

-> #4 (&cmd->lock){+.+.}-{4:4}:
       __mutex_lock+0x19d/0x1550
       nbd_queue_rq+0xc1/0xff0
       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+0xc3d/0x1630
       worker_thread+0xa47/0xfb0
       kthread+0x38b/0x480
       ret_from_fork+0x514/0xb70
       ret_from_fork_asm+0x1a/0x30

-> #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+0x6b8/0xdb0
       add_disk_fwnode+0x100/0x3a0
       nbd_dev_add+0x733/0xb60
       nbd_init+0x168/0x1f0
       do_one_initcall+0x250/0x870
       do_initcall_level+0x10a/0x1a0
       do_initcalls+0x59/0xa0
       kernel_init_freeable+0x29d/0x3e0
       kernel_init+0x22/0x1d0
       ret_from_fork+0x514/0xb70
       ret_from_fork_asm+0x1a/0x30

-> #2 (&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+0x167d/0x1cd0
       genl_family_rcv_msg_doit+0x233/0x340
       genl_rcv_msg+0x614/0x7a0
       netlink_rcv_skb+0x226/0x4a0
       genl_rcv+0x28/0x40
       netlink_unicast+0x7bd/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+0x166/0x520
       entry_SYSCALL_64_after_hwframe+0x77/0x7f

-> #1 (&q->q_usage_counter(io)#50){++++}-{0:0}:
       blk_alloc_queue+0x544/0x690
       __blk_mq_alloc_disk+0x194/0x390
       nbd_dev_add+0x494/0xb60
       nbd_init+0x168/0x1f0
       do_one_initcall+0x250/0x870
       do_initcall_level+0x10a/0x1a0
       do_initcalls+0x59/0xa0
       kernel_init_freeable+0x29d/0x3e0
       kernel_init+0x22/0x1d0
       ret_from_fork+0x514/0xb70
       ret_from_fork_asm+0x1a/0x30

-> #0 (fs_reclaim){+.+.}-{0:0}:
       __lock_acquire+0x164c/0x2de0
       lock_acquire+0x115/0x350
       fs_reclaim_acquire+0x71/0x100
       prepare_alloc_pages+0x149/0x600
       __alloc_frozen_pages_noprof+0x185/0x5a0
       alloc_pages_mpol+0x21e/0x390
       alloc_pages_noprof+0xb1/0x2b0
       pte_alloc_one+0x22/0x370
       __pte_alloc+0x25/0x1a0
       insert_pages+0x579/0x720
       tcp_zerocopy_receive+0x14cc/0x2560
       do_tcp_getsockopt+0x224b/0x2b50
       tcp_getsockopt+0x83/0x130
       do_sock_getsockopt+0x51d/0x7e0
       __x64_sys_getsockopt+0x1a4/0x240
       do_syscall_64+0x166/0x520
       entry_SYSCALL_64_after_hwframe+0x77/0x7f

other info that might help us debug this:

Chain exists of:
  fs_reclaim --> &mm->mmap_lock --> vm_lock

 Possible unsafe locking scenario:

       CPU0                    CPU1
       ----                    ----
  rlock(vm_lock);
                               lock(&mm->mmap_lock);
                               lock(vm_lock);
  lock(fs_reclaim);

 *** DEADLOCK ***

locks held by syz.0.3042/16897: 2, last CPU#0:
 #0: ffff888043430260 (sk_lock-AF_INET6){+.+.}-{0:0}, at: do_tcp_getsockopt+0x2238/0x2b50
 #1: ffff88811299c508 (vm_lock){++++}-{0:0}, at: lock_vma_under_rcu+0x1d1/0x500

stack backtrace:
CPU: 0 UID: 0 PID: 16897 Comm: syz.0.3042 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+0x2e2/0x300
 check_noncircular+0x12f/0x150
 __lock_acquire+0x164c/0x2de0
 lock_acquire+0x115/0x350
 fs_reclaim_acquire+0x71/0x100
 prepare_alloc_pages+0x149/0x600
 __alloc_frozen_pages_noprof+0x185/0x5a0
 alloc_pages_mpol+0x21e/0x390
 alloc_pages_noprof+0xb1/0x2b0
 pte_alloc_one+0x22/0x370
 __pte_alloc+0x25/0x1a0
 insert_pages+0x579/0x720
 tcp_zerocopy_receive+0x14cc/0x2560
 do_tcp_getsockopt+0x224b/0x2b50
 tcp_getsockopt+0x83/0x130
 do_sock_getsockopt+0x51d/0x7e0
 __x64_sys_getsockopt+0x1a4/0x240
 do_syscall_64+0x166/0x520
 entry_SYSCALL_64_after_hwframe+0x77/0x7f
RIP: 0033:0x7fe7b8b9e559
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:00007fe7b9a07028 EFLAGS: 00000246 ORIG_RAX: 0000000000000037
RAX: ffffffffffffffda RBX: 00007fe7b8e25fa0 RCX: 00007fe7b8b9e559
RDX: 0000000000000023 RSI: 0000000000000006 RDI: 0000000000000006
RBP: 00007fe7b8c358b0 R08: 0000200000011f40 R09: 0000000000000000
R10: 0000200000011f00 R11: 0000000000000246 R12: 0000000000000000
R13: 00007fe7b8e26038 R14: 00007fe7b8e25fa0 R15: 00007ffc37339278
 </TASK>
