======================================================
WARNING: possible circular locking dependency detected
syzkaller #0 Not tainted
------------------------------------------------------
syz.4.71/7027 is trying to acquire lock:
ffff0000c7f501d0 (&mm->mmap_lock){++++}-{4:4}, at: __might_fault+0x9c/0x124 mm/memory.c:6957

but task is already holding lock:
ffff0000fd298b18 (sk_lock-AF_VSOCK){+.+.}-{0:0}, at: lock_sock include/net/sock.h:1669 [inline]
ffff0000fd298b18 (sk_lock-AF_VSOCK){+.+.}-{0:0}, at: vsock_connectible_setsockopt+0xf4/0x634 net/vmw_vsock/af_vsock.c:1872

which lock already depends on the new lock.


the existing dependency chain (in reverse order) is:

-> #7 (sk_lock-AF_VSOCK){+.+.}-{0:0}:
       lock_sock_nested+0x58/0x118 net/core/sock.c:3711
       lock_sock include/net/sock.h:1669 [inline]
       vsock_shutdown+0x70/0x280 net/vmw_vsock/af_vsock.c:1103
       kernel_sock_shutdown+0x6c/0x80 net/socket.c:3701
       nbd_mark_nsock_dead+0x2a4/0x534 drivers/block/nbd.c:318
       recv_work+0x1cf8/0x2044 drivers/block/nbd.c:1018
       process_one_work+0x7e8/0x155c kernel/workqueue.c:3236
       process_scheduled_works kernel/workqueue.c:3319 [inline]
       worker_thread+0x958/0xed8 kernel/workqueue.c:3400
       kthread+0x5fc/0x75c kernel/kthread.c:463
       ret_from_fork+0x10/0x20 arch/arm64/kernel/entry.S:844

-> #6 (&nsock->tx_lock){+.+.}-{4:4}:
       __mutex_lock_common+0x1d0/0x2678 kernel/locking/mutex.c:598
       __mutex_lock kernel/locking/mutex.c:760 [inline]
       mutex_lock_nested+0x2c/0x38 kernel/locking/mutex.c:812
       nbd_handle_cmd drivers/block/nbd.c:1140 [inline]
       nbd_queue_rq+0x20c/0xc48 drivers/block/nbd.c:1204
       blk_mq_dispatch_rq_list+0x890/0x1548 block/blk-mq.c:2120
       __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+0xa7c/0x10e4 block/blk-mq-sched.c:307
       blk_mq_sched_dispatch_requests+0xa4/0x154 block/blk-mq-sched.c:329
       blk_mq_run_hw_queue+0x2d0/0x4a4 block/blk-mq.c:2358
       blk_mq_dispatch_list+0xa00/0xaf8 block/blk-mq.c:-1
       blk_mq_flush_plug_list+0x3a4/0x488 block/blk-mq.c:2967
       __blk_flush_plug+0x330/0x408 block/blk-core.c:1220
       blk_finish_plug block/blk-core.c:1247 [inline]
       __submit_bio+0x3f4/0x4d8 block/blk-core.c:649
       __submit_bio_noacct_mq block/blk-core.c:722 [inline]
       submit_bio_noacct_nocheck+0x390/0xaac block/blk-core.c:751
       submit_bio_noacct+0xc94/0x177c block/blk-core.c:874
       submit_bio+0x3b4/0x550 block/blk-core.c:916
       submit_bh_wbc+0x3ec/0x4bc fs/buffer.c:2824
       submit_bh fs/buffer.c:2829 [inline]
       block_read_full_folio+0x734/0x824 fs/buffer.c:2461
       blkdev_read_folio+0x28/0x38 block/fops.c:491
       filemap_read_folio+0xec/0x2f8 mm/filemap.c:2413
       do_read_cache_folio+0x364/0x5bc mm/filemap.c:3957
       read_cache_folio+0x68/0x88 mm/filemap.c:3989
       read_mapping_folio include/linux/pagemap.h:991 [inline]
       read_part_sector+0xcc/0x6fc block/partitions/core.c:722
       adfspart_check_ICS+0xa0/0x83c block/partitions/acorn.c:360
       check_partition block/partitions/core.c:141 [inline]
       blk_add_partitions block/partitions/core.c:589 [inline]
       bdev_disk_changed+0x674/0x11fc block/partitions/core.c:693
       blkdev_get_whole+0x2b0/0x4a4 block/bdev.c:748
       bdev_open+0x3b0/0xc20 block/bdev.c:957
       blkdev_open+0x300/0x440 block/fops.c:691
       do_dentry_open+0x7a4/0x10bc fs/open.c:965
       vfs_open+0x44/0x2d4 fs/open.c:1095
       do_open fs/namei.c:3887 [inline]
       path_openat+0x2424/0x2c40 fs/namei.c:4046
       do_filp_open+0x18c/0x36c fs/namei.c:4073
       do_sys_openat2+0x11c/0x1b4 fs/open.c:1435
       do_sys_open fs/open.c:1450 [inline]
       __do_sys_openat fs/open.c:1466 [inline]
       __se_sys_openat fs/open.c:1461 [inline]
       __arm64_sys_openat+0x120/0x158 fs/open.c:1461
       __invoke_syscall arch/arm64/kernel/syscall.c:35 [inline]
       invoke_syscall+0x98/0x2b8 arch/arm64/kernel/syscall.c:49
       el0_svc_common+0x130/0x23c arch/arm64/kernel/syscall.c:132
       do_el0_svc+0x48/0x58 arch/arm64/kernel/syscall.c:151
       el0_svc+0x5c/0x254 arch/arm64/kernel/entry-common.c:744
       el0t_64_sync_handler+0x84/0x12c arch/arm64/kernel/entry-common.c:763
       el0t_64_sync+0x198/0x19c arch/arm64/kernel/entry.S:596

-> #5 (&cmd->lock){+.+.}-{4:4}:
       __mutex_lock_common+0x1d0/0x2678 kernel/locking/mutex.c:598
       __mutex_lock kernel/locking/mutex.c:760 [inline]
       mutex_lock_nested+0x2c/0x38 kernel/locking/mutex.c:812
       nbd_queue_rq+0xb4/0xc48 drivers/block/nbd.c:1196
       blk_mq_dispatch_rq_list+0x890/0x1548 block/blk-mq.c:2120
       __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+0xa7c/0x10e4 block/blk-mq-sched.c:307
       blk_mq_sched_dispatch_requests+0xa4/0x154 block/blk-mq-sched.c:329
       blk_mq_run_hw_queue+0x2d0/0x4a4 block/blk-mq.c:2358
       blk_mq_dispatch_list+0xa00/0xaf8 block/blk-mq.c:-1
       blk_mq_flush_plug_list+0x3a4/0x488 block/blk-mq.c:2967
       __blk_flush_plug+0x330/0x408 block/blk-core.c:1220
       blk_finish_plug block/blk-core.c:1247 [inline]
       __submit_bio+0x3f4/0x4d8 block/blk-core.c:649
       __submit_bio_noacct_mq block/blk-core.c:722 [inline]
       submit_bio_noacct_nocheck+0x390/0xaac block/blk-core.c:751
       submit_bio_noacct+0xc94/0x177c block/blk-core.c:874
       submit_bio+0x3b4/0x550 block/blk-core.c:916
       submit_bh_wbc+0x3ec/0x4bc fs/buffer.c:2824
       submit_bh fs/buffer.c:2829 [inline]
       block_read_full_folio+0x734/0x824 fs/buffer.c:2461
       blkdev_read_folio+0x28/0x38 block/fops.c:491
       filemap_read_folio+0xec/0x2f8 mm/filemap.c:2413
       do_read_cache_folio+0x364/0x5bc mm/filemap.c:3957
       read_cache_folio+0x68/0x88 mm/filemap.c:3989
       read_mapping_folio include/linux/pagemap.h:991 [inline]
       read_part_sector+0xcc/0x6fc block/partitions/core.c:722
       adfspart_check_ICS+0xa0/0x83c block/partitions/acorn.c:360
       check_partition block/partitions/core.c:141 [inline]
       blk_add_partitions block/partitions/core.c:589 [inline]
       bdev_disk_changed+0x674/0x11fc block/partitions/core.c:693
       blkdev_get_whole+0x2b0/0x4a4 block/bdev.c:748
       bdev_open+0x3b0/0xc20 block/bdev.c:957
       blkdev_open+0x300/0x440 block/fops.c:691
       do_dentry_open+0x7a4/0x10bc fs/open.c:965
       vfs_open+0x44/0x2d4 fs/open.c:1095
       do_open fs/namei.c:3887 [inline]
       path_openat+0x2424/0x2c40 fs/namei.c:4046
       do_filp_open+0x18c/0x36c fs/namei.c:4073
       do_sys_openat2+0x11c/0x1b4 fs/open.c:1435
       do_sys_open fs/open.c:1450 [inline]
       __do_sys_openat fs/open.c:1466 [inline]
       __se_sys_openat fs/open.c:1461 [inline]
       __arm64_sys_openat+0x120/0x158 fs/open.c:1461
       __invoke_syscall arch/arm64/kernel/syscall.c:35 [inline]
       invoke_syscall+0x98/0x2b8 arch/arm64/kernel/syscall.c:49
       el0_svc_common+0x130/0x23c arch/arm64/kernel/syscall.c:132
       do_el0_svc+0x48/0x58 arch/arm64/kernel/syscall.c:151
       el0_svc+0x5c/0x254 arch/arm64/kernel/entry-common.c:744
       el0t_64_sync_handler+0x84/0x12c arch/arm64/kernel/entry-common.c:763
       el0t_64_sync+0x198/0x19c arch/arm64/kernel/entry.S:596

-> #4 (set->srcu){.+.+}-{0:0}:
       srcu_lock_sync+0x2c/0x38 include/linux/srcu.h:173
       __synchronize_srcu+0xa0/0x348 kernel/rcu/srcutree.c:1429
       synchronize_srcu+0x2cc/0x338 kernel/rcu/srcutree.c:-1
       blk_mq_wait_quiesce_done block/blk-mq.c:283 [inline]
       blk_mq_quiesce_queue+0x118/0x16c block/blk-mq.c:303
       elevator_switch+0x12c/0x410 block/elevator.c:588
       elevator_change+0x264/0x3cc block/elevator.c:690
       elevator_set_default+0x138/0x21c block/elevator.c:766
       blk_register_queue+0x2b4/0x338 block/blk-sysfs.c:904
       __add_disk+0x560/0xb90 block/genhd.c:528
       add_disk_fwnode+0xdc/0x438 block/genhd.c:597
       device_add_disk+0x38/0x4c block/genhd.c:627
       add_disk include/linux/blkdev.h:774 [inline]
       nbd_dev_add+0x560/0x820 drivers/block/nbd.c:1973
       nbd_init+0x15c/0x174 drivers/block/nbd.c:2680
       do_one_initcall+0x250/0x990 init/main.c:1269
       do_initcall_level+0x128/0x1c4 init/main.c:1331
       do_initcalls+0x70/0xd0 init/main.c:1347
       do_basic_setup+0x78/0x8c init/main.c:1366
       kernel_init_freeable+0x268/0x39c init/main.c:1579
       kernel_init+0x24/0x1dc init/main.c:1469
       ret_from_fork+0x10/0x20 arch/arm64/kernel/entry.S:844

-> #3 (&q->elevator_lock){+.+.}-{4:4}:
       __mutex_lock_common+0x1d0/0x2678 kernel/locking/mutex.c:598
       __mutex_lock kernel/locking/mutex.c:760 [inline]
       mutex_lock_nested+0x2c/0x38 kernel/locking/mutex.c:812
       elevator_change+0x16c/0x3cc block/elevator.c:688
       elevator_set_none+0x48/0xac block/elevator.c:781
       blk_mq_elv_switch_none block/blk-mq.c:5023 [inline]
       __blk_mq_update_nr_hw_queues block/blk-mq.c:5066 [inline]
       blk_mq_update_nr_hw_queues+0x4c8/0x15f4 block/blk-mq.c:5124
       nbd_start_device+0x158/0xa48 drivers/block/nbd.c:1478
       nbd_genl_connect+0xf88/0x158c drivers/block/nbd.c:2228
       genl_family_rcv_msg_doit+0x1d8/0x2bc net/netlink/genetlink.c:1115
       genl_family_rcv_msg net/netlink/genetlink.c:1195 [inline]
       genl_rcv_msg+0x450/0x624 net/netlink/genetlink.c:1210
       netlink_rcv_skb+0x220/0x3fc net/netlink/af_netlink.c:2552
       genl_rcv+0x38/0x50 net/netlink/genetlink.c:1219
       netlink_unicast_kernel net/netlink/af_netlink.c:1320 [inline]
       netlink_unicast+0x694/0x8c4 net/netlink/af_netlink.c:1346
       netlink_sendmsg+0x648/0x930 net/netlink/af_netlink.c:1896
       sock_sendmsg_nosec net/socket.c:714 [inline]
       __sock_sendmsg net/socket.c:729 [inline]
       ____sys_sendmsg+0x490/0x7b8 net/socket.c:2614
       ___sys_sendmsg+0x204/0x278 net/socket.c:2668
       __sys_sendmsg net/socket.c:2700 [inline]
       __do_sys_sendmsg net/socket.c:2705 [inline]
       __se_sys_sendmsg net/socket.c:2703 [inline]
       __arm64_sys_sendmsg+0x184/0x238 net/socket.c:2703
       __invoke_syscall arch/arm64/kernel/syscall.c:35 [inline]
       invoke_syscall+0x98/0x2b8 arch/arm64/kernel/syscall.c:49
       el0_svc_common+0x130/0x23c arch/arm64/kernel/syscall.c:132
       do_el0_svc+0x48/0x58 arch/arm64/kernel/syscall.c:151
       el0_svc+0x5c/0x254 arch/arm64/kernel/entry-common.c:744
       el0t_64_sync_handler+0x84/0x12c arch/arm64/kernel/entry-common.c:763
       el0t_64_sync+0x198/0x19c arch/arm64/kernel/entry.S:596

-> #2 (&q->q_usage_counter(io)#33){++++}-{0:0}:
       blk_alloc_queue+0x48c/0x54c block/blk-core.c:461
       blk_mq_alloc_queue block/blk-mq.c:4400 [inline]
       __blk_mq_alloc_disk+0x124/0x304 block/blk-mq.c:4447
       nbd_dev_add+0x398/0x820 drivers/block/nbd.c:1943
       nbd_init+0x15c/0x174 drivers/block/nbd.c:2680
       do_one_initcall+0x250/0x990 init/main.c:1269
       do_initcall_level+0x128/0x1c4 init/main.c:1331
       do_initcalls+0x70/0xd0 init/main.c:1347
       do_basic_setup+0x78/0x8c init/main.c:1366
       kernel_init_freeable+0x268/0x39c init/main.c:1579
       kernel_init+0x24/0x1dc init/main.c:1469
       ret_from_fork+0x10/0x20 arch/arm64/kernel/entry.S:844

-> #1 (fs_reclaim){+.+.}-{0:0}:
       __fs_reclaim_acquire mm/page_alloc.c:4234 [inline]
       fs_reclaim_acquire+0x8c/0x118 mm/page_alloc.c:4248
       might_alloc include/linux/sched/mm.h:318 [inline]
       slab_pre_alloc_hook mm/slub.c:4142 [inline]
       slab_alloc_node mm/slub.c:4220 [inline]
       kmem_cache_alloc_noprof+0x58/0x3e8 mm/slub.c:4247
       mt_alloc_one lib/maple_tree.c:176 [inline]
       mas_alloc_nodes+0x268/0x788 lib/maple_tree.c:1255
       mas_node_count_gfp lib/maple_tree.c:1337 [inline]
       mas_preallocate+0x4fc/0x7e8 lib/maple_tree.c:5537
       vma_iter_prealloc mm/vma.h:462 [inline]
       vma_link+0x100/0x5ac mm/vma.c:1792
       insert_vm_struct+0x18c/0x244 mm/vma.c:3196
       create_init_stack_vma+0x24c/0x56c mm/vma_exec.c:143
       bprm_mm_init fs/exec.c:274 [inline]
       alloc_bprm+0x3d4/0x548 fs/exec.c:1466
       kernel_execve+0xa4/0x7f4 fs/exec.c:1885
       run_init_process+0x1bc/0x1ec init/main.c:1390
       try_to_run_init_process+0x20/0x7c init/main.c:1397
       kernel_init+0xa8/0x1dc init/main.c:1525
       ret_from_fork+0x10/0x20 arch/arm64/kernel/entry.S:844

-> #0 (&mm->mmap_lock){++++}-{4:4}:
       check_prev_add kernel/locking/lockdep.c:3165 [inline]
       check_prevs_add kernel/locking/lockdep.c:3284 [inline]
       validate_chain kernel/locking/lockdep.c:3908 [inline]
       __lock_acquire+0x1774/0x30a4 kernel/locking/lockdep.c:5237
       lock_acquire+0x14c/0x2e0 kernel/locking/lockdep.c:5868
       __might_fault+0xc4/0x124 mm/memory.c:6958
       _inline_copy_from_user+0x38/0x33c include/linux/uaccess.h:162
       copy_from_user include/linux/uaccess.h:210 [inline]
       copy_from_sockptr_offset include/linux/sockptr.h:48 [inline]
       copy_from_sockptr include/linux/sockptr.h:61 [inline]
       sock_copy_user_timeval+0x1c8/0x2ec net/core/sock.c:411
       vsock_connectible_setsockopt+0x294/0x634 net/vmw_vsock/af_vsock.c:1925
       do_sock_setsockopt+0x1ec/0x328 net/socket.c:2344
       __sys_setsockopt net/socket.c:2369 [inline]
       __do_sys_setsockopt net/socket.c:2375 [inline]
       __se_sys_setsockopt net/socket.c:2372 [inline]
       __arm64_sys_setsockopt+0x170/0x1e0 net/socket.c:2372
       __invoke_syscall arch/arm64/kernel/syscall.c:35 [inline]
       invoke_syscall+0x98/0x2b8 arch/arm64/kernel/syscall.c:49
       el0_svc_common+0x130/0x23c arch/arm64/kernel/syscall.c:132
       do_el0_svc+0x48/0x58 arch/arm64/kernel/syscall.c:151
       el0_svc+0x5c/0x254 arch/arm64/kernel/entry-common.c:744
       el0t_64_sync_handler+0x84/0x12c arch/arm64/kernel/entry-common.c:763
       el0t_64_sync+0x198/0x19c arch/arm64/kernel/entry.S:596

other info that might help us debug this:

Chain exists of:
  &mm->mmap_lock --> &nsock->tx_lock --> sk_lock-AF_VSOCK

 Possible unsafe locking scenario:

       CPU0                    CPU1
       ----                    ----
  lock(sk_lock-AF_VSOCK);
                               lock(&nsock->tx_lock);
                               lock(sk_lock-AF_VSOCK);
  rlock(&mm->mmap_lock);

 *** DEADLOCK ***

1 lock held by syz.4.71/7027:
 #0: ffff0000fd298b18 (sk_lock-AF_VSOCK){+.+.}-{0:0}, at: lock_sock include/net/sock.h:1669 [inline]
 #0: ffff0000fd298b18 (sk_lock-AF_VSOCK){+.+.}-{0:0}, at: vsock_connectible_setsockopt+0xf4/0x634 net/vmw_vsock/af_vsock.c:1872

stack backtrace:
CPU: 1 UID: 0 PID: 7027 Comm: syz.4.71 Not tainted syzkaller #0 PREEMPT 
Hardware name: Google Google Compute Engine/Google Compute Engine, BIOS Google 06/30/2025
Call trace:
 show_stack+0x2c/0x3c arch/arm64/kernel/stacktrace.c:499 (C)
 __dump_stack+0x30/0x40 lib/dump_stack.c:94
 dump_stack_lvl+0xd8/0x12c lib/dump_stack.c:120
 dump_stack+0x1c/0x28 lib/dump_stack.c:129
 print_circular_bug+0x324/0x32c kernel/locking/lockdep.c:2043
 check_noncircular+0x154/0x174 kernel/locking/lockdep.c:2175
 check_prev_add kernel/locking/lockdep.c:3165 [inline]
 check_prevs_add kernel/locking/lockdep.c:3284 [inline]
 validate_chain kernel/locking/lockdep.c:3908 [inline]
 __lock_acquire+0x1774/0x30a4 kernel/locking/lockdep.c:5237
 lock_acquire+0x14c/0x2e0 kernel/locking/lockdep.c:5868
 __might_fault+0xc4/0x124 mm/memory.c:6958
 _inline_copy_from_user+0x38/0x33c include/linux/uaccess.h:162
 copy_from_user include/linux/uaccess.h:210 [inline]
 copy_from_sockptr_offset include/linux/sockptr.h:48 [inline]
 copy_from_sockptr include/linux/sockptr.h:61 [inline]
 sock_copy_user_timeval+0x1c8/0x2ec net/core/sock.c:411
 vsock_connectible_setsockopt+0x294/0x634 net/vmw_vsock/af_vsock.c:1925
 do_sock_setsockopt+0x1ec/0x328 net/socket.c:2344
 __sys_setsockopt net/socket.c:2369 [inline]
 __do_sys_setsockopt net/socket.c:2375 [inline]
 __se_sys_setsockopt net/socket.c:2372 [inline]
 __arm64_sys_setsockopt+0x170/0x1e0 net/socket.c:2372
 __invoke_syscall arch/arm64/kernel/syscall.c:35 [inline]
 invoke_syscall+0x98/0x2b8 arch/arm64/kernel/syscall.c:49
 el0_svc_common+0x130/0x23c arch/arm64/kernel/syscall.c:132
 do_el0_svc+0x48/0x58 arch/arm64/kernel/syscall.c:151
 el0_svc+0x5c/0x254 arch/arm64/kernel/entry-common.c:744
 el0t_64_sync_handler+0x84/0x12c arch/arm64/kernel/entry-common.c:763
 el0t_64_sync+0x198/0x19c arch/arm64/kernel/entry.S:596