Dev nbd5: unable to read RDB block 0
 nbd5: unable to read partition table
======================================================
WARNING: possible circular locking dependency detected
6.14.0-rc4-syzkaller-00052-gac9c34d1e45a #0 Not tainted
------------------------------------------------------
udevd/5899 is trying to acquire lock:
ffff88814338b7c8 (&q->q_usage_counter(io)#54){++++}-{0:0}, at: __submit_bio+0x2cf/0x6a0 block/blk-core.c:628

but task is already holding lock:
ffff888023a6f0c0 (mapping.invalidate_lock#2){.+.+}-{4:4}, at: filemap_invalidate_lock_shared include/linux/fs.h:932 [inline]
ffff888023a6f0c0 (mapping.invalidate_lock#2){.+.+}-{4:4}, at: page_cache_ra_unbounded+0x156/0x820 mm/readahead.c:229

which lock already depends on the new lock.


the existing dependency chain (in reverse order) is:

-> #7 (mapping.invalidate_lock#2){.+.+}-{4:4}:
       lock_acquire+0x1ed/0x550 kernel/locking/lockdep.c:5851
       down_read+0xb1/0xa40 kernel/locking/rwsem.c:1524
       filemap_invalidate_lock_shared include/linux/fs.h:932 [inline]
       filemap_fault+0xb5f/0x16c0 mm/filemap.c:3454
       __do_fault+0x137/0x390 mm/memory.c:4988
       do_read_fault mm/memory.c:5403 [inline]
       do_fault mm/memory.c:5537 [inline]
       do_pte_missing mm/memory.c:4058 [inline]
       handle_pte_fault mm/memory.c:5900 [inline]
       __handle_mm_fault+0x4c44/0x70f0 mm/memory.c:6043
       handle_mm_fault+0x3e5/0x8d0 mm/memory.c:6212
       do_user_addr_fault arch/x86/mm/fault.c:1388 [inline]
       handle_page_fault arch/x86/mm/fault.c:1480 [inline]
       exc_page_fault+0x2b9/0x8b0 arch/x86/mm/fault.c:1538
       asm_exc_page_fault+0x26/0x30 arch/x86/include/asm/idtentry.h:623
       __get_user_8+0x18/0x30 arch/x86/lib/getuser.S:98
       __do_sys_io_setup fs/aio.c:1388 [inline]
       __se_sys_io_setup+0x2d/0x1a0 fs/aio.c:1382
       do_syscall_x64 arch/x86/entry/common.c:52 [inline]
       do_syscall_64+0xf3/0x230 arch/x86/entry/common.c:83
       entry_SYSCALL_64_after_hwframe+0x77/0x7f

-> #6 (&mm->mmap_lock){++++}-{4:4}:
       lock_acquire+0x1ed/0x550 kernel/locking/lockdep.c:5851
       __might_fault+0xc6/0x120 mm/memory.c:6851
       _copy_from_iter+0x100/0x1c40 lib/iov_iter.c:259
       copy_from_iter include/linux/uio.h:228 [inline]
       copy_from_iter_full include/linux/uio.h:245 [inline]
       skb_do_copy_data_nocache include/net/sock.h:2196 [inline]
       skb_copy_to_page_nocache include/net/sock.h:2222 [inline]
       tcp_sendmsg_locked+0x213d/0x5330 net/ipv4/tcp.c:1222
       tcp_sendmsg+0x30/0x50 net/ipv4/tcp.c:1358
       sock_sendmsg_nosec net/socket.c:718 [inline]
       __sock_sendmsg+0x1a6/0x270 net/socket.c:733
       sock_write_iter+0x2d7/0x3f0 net/socket.c:1137
       new_sync_write fs/read_write.c:586 [inline]
       vfs_write+0xad1/0xd10 fs/read_write.c:679
       ksys_write+0x18f/0x2b0 fs/read_write.c:731
       do_syscall_x64 arch/x86/entry/common.c:52 [inline]
       do_syscall_64+0xf3/0x230 arch/x86/entry/common.c:83
       entry_SYSCALL_64_after_hwframe+0x77/0x7f

-> #5 (sk_lock-AF_INET){+.+.}-{0:0}:
       lock_acquire+0x1ed/0x550 kernel/locking/lockdep.c:5851
       lock_sock_nested+0x48/0x100 net/core/sock.c:3645
       lock_sock include/net/sock.h:1624 [inline]
       inet_autobind net/ipv4/af_inet.c:178 [inline]
       inet_send_prepare net/ipv4/af_inet.c:837 [inline]
       inet_sendmsg+0x120/0x390 net/ipv4/af_inet.c:848
       sock_sendmsg_nosec net/socket.c:718 [inline]
       __sock_sendmsg+0x1a6/0x270 net/socket.c:733
       sock_sendmsg+0x16c/0x250 net/socket.c:756
       __sock_xmit+0x219/0x4e0 drivers/block/nbd.c:574
       sock_xmit drivers/block/nbd.c:602 [inline]
       nbd_send_cmd+0x996/0x2110 drivers/block/nbd.c:712
       nbd_handle_cmd drivers/block/nbd.c:1174 [inline]
       nbd_queue_rq+0xcd5/0xef0 drivers/block/nbd.c:1204
       blk_mq_dispatch_rq_list+0xad5/0x19d0 block/blk-mq.c:2120
       __blk_mq_do_dispatch_sched block/blk-mq-sched.c:170 [inline]
       blk_mq_do_dispatch_sched block/blk-mq-sched.c:184 [inline]
       __blk_mq_sched_dispatch_requests+0xb8a/0x1840 block/blk-mq-sched.c:309
       blk_mq_sched_dispatch_requests+0xd6/0x190 block/blk-mq-sched.c:331
       blk_mq_run_hw_queue+0x354/0x500 block/blk-mq.c:2354
       blk_mq_flush_plug_list+0x118e/0x1870 block/blk-mq.c:2917
       __blk_flush_plug+0x420/0x500 block/blk-core.c:1213
       blk_finish_plug block/blk-core.c:1240 [inline]
       __submit_bio+0x54a/0x6a0 block/blk-core.c:642
       __submit_bio_noacct_mq block/blk-core.c:715 [inline]
       submit_bio_noacct_nocheck+0x4d3/0xe30 block/blk-core.c:744
       submit_bh fs/buffer.c:2819 [inline]
       __bread_slow fs/buffer.c:1264 [inline]
       __bread_gfp+0x23c/0x400 fs/buffer.c:1488
       sb_bread include/linux/buffer_head.h:346 [inline]
       udf_check_vsd fs/udf/super.c:772 [inline]
       udf_load_vrs+0x394/0x1130 fs/udf/super.c:2006
       udf_fill_super+0x5f2/0x1cb0 fs/udf/super.c:2192
       get_tree_bdev_flags+0x48e/0x5c0 fs/super.c:1636
       vfs_get_tree+0x92/0x2b0 fs/super.c:1814
       do_new_mount+0x2be/0xb40 fs/namespace.c:3560
       do_mount fs/namespace.c:3900 [inline]
       __do_sys_mount fs/namespace.c:4111 [inline]
       __se_sys_mount+0x2d6/0x3c0 fs/namespace.c:4088
       do_syscall_x64 arch/x86/entry/common.c:52 [inline]
       do_syscall_64+0xf3/0x230 arch/x86/entry/common.c:83
       entry_SYSCALL_64_after_hwframe+0x77/0x7f

-> #4 (&nsock->tx_lock){+.+.}-{4:4}:
       lock_acquire+0x1ed/0x550 kernel/locking/lockdep.c:5851
       __mutex_lock_common kernel/locking/mutex.c:585 [inline]
       __mutex_lock+0x19c/0x1010 kernel/locking/mutex.c:730
       nbd_handle_cmd drivers/block/nbd.c:1140 [inline]
       nbd_queue_rq+0x262/0xef0 drivers/block/nbd.c:1204
       blk_mq_dispatch_rq_list+0xad5/0x19d0 block/blk-mq.c:2120
       __blk_mq_do_dispatch_sched block/blk-mq-sched.c:170 [inline]
       blk_mq_do_dispatch_sched block/blk-mq-sched.c:184 [inline]
       __blk_mq_sched_dispatch_requests+0xb8a/0x1840 block/blk-mq-sched.c:309
       blk_mq_sched_dispatch_requests+0xd6/0x190 block/blk-mq-sched.c:331
       blk_mq_run_hw_queue+0x354/0x500 block/blk-mq.c:2354
       blk_mq_flush_plug_list+0x118e/0x1870 block/blk-mq.c:2917
       __blk_flush_plug+0x420/0x500 block/blk-core.c:1213
       blk_finish_plug block/blk-core.c:1240 [inline]
       __submit_bio+0x54a/0x6a0 block/blk-core.c:642
       __submit_bio_noacct_mq block/blk-core.c:715 [inline]
       submit_bio_noacct_nocheck+0x4d3/0xe30 block/blk-core.c:744
       submit_bh fs/buffer.c:2819 [inline]
       __bread_slow fs/buffer.c:1264 [inline]
       __bread_gfp+0x23c/0x400 fs/buffer.c:1488
       sb_bread include/linux/buffer_head.h:346 [inline]
       udf_check_vsd fs/udf/super.c:772 [inline]
       udf_load_vrs+0x394/0x1130 fs/udf/super.c:2006
       udf_fill_super+0x5f2/0x1cb0 fs/udf/super.c:2192
       get_tree_bdev_flags+0x48e/0x5c0 fs/super.c:1636
       vfs_get_tree+0x92/0x2b0 fs/super.c:1814
       do_new_mount+0x2be/0xb40 fs/namespace.c:3560
       do_mount fs/namespace.c:3900 [inline]
       __do_sys_mount fs/namespace.c:4111 [inline]
       __se_sys_mount+0x2d6/0x3c0 fs/namespace.c:4088
       do_syscall_x64 arch/x86/entry/common.c:52 [inline]
       do_syscall_64+0xf3/0x230 arch/x86/entry/common.c:83
       entry_SYSCALL_64_after_hwframe+0x77/0x7f

-> #3 (&cmd->lock){+.+.}-{4:4}:
       lock_acquire+0x1ed/0x550 kernel/locking/lockdep.c:5851
       __mutex_lock_common kernel/locking/mutex.c:585 [inline]
       __mutex_lock+0x19c/0x1010 kernel/locking/mutex.c:730
       nbd_queue_rq+0xcf/0xef0 drivers/block/nbd.c:1196
       blk_mq_dispatch_rq_list+0xad5/0x19d0 block/blk-mq.c:2120
       __blk_mq_do_dispatch_sched block/blk-mq-sched.c:170 [inline]
       blk_mq_do_dispatch_sched block/blk-mq-sched.c:184 [inline]
       __blk_mq_sched_dispatch_requests+0xb8a/0x1840 block/blk-mq-sched.c:309
       blk_mq_sched_dispatch_requests+0xd6/0x190 block/blk-mq-sched.c:331
       blk_mq_run_hw_queue+0x354/0x500 block/blk-mq.c:2354
       blk_mq_flush_plug_list+0x118e/0x1870 block/blk-mq.c:2917
       __blk_flush_plug+0x420/0x500 block/blk-core.c:1213
       blk_finish_plug block/blk-core.c:1240 [inline]
       __submit_bio+0x54a/0x6a0 block/blk-core.c:642
       __submit_bio_noacct_mq block/blk-core.c:715 [inline]
       submit_bio_noacct_nocheck+0x4d3/0xe30 block/blk-core.c:744
       submit_bh fs/buffer.c:2819 [inline]
       __bread_slow fs/buffer.c:1264 [inline]
       __bread_gfp+0x23c/0x400 fs/buffer.c:1488
       sb_bread include/linux/buffer_head.h:346 [inline]
       udf_check_vsd fs/udf/super.c:772 [inline]
       udf_load_vrs+0x394/0x1130 fs/udf/super.c:2006
       udf_fill_super+0x5f2/0x1cb0 fs/udf/super.c:2192
       get_tree_bdev_flags+0x48e/0x5c0 fs/super.c:1636
       vfs_get_tree+0x92/0x2b0 fs/super.c:1814
       do_new_mount+0x2be/0xb40 fs/namespace.c:3560
       do_mount fs/namespace.c:3900 [inline]
       __do_sys_mount fs/namespace.c:4111 [inline]
       __se_sys_mount+0x2d6/0x3c0 fs/namespace.c:4088
       do_syscall_x64 arch/x86/entry/common.c:52 [inline]
       do_syscall_64+0xf3/0x230 arch/x86/entry/common.c:83
       entry_SYSCALL_64_after_hwframe+0x77/0x7f

-> #2 (set->srcu){.+.+}-{0:0}:
       lock_sync+0x18b/0x310 kernel/locking/lockdep.c:5899
       srcu_lock_sync include/linux/srcu.h:176 [inline]
       __synchronize_srcu+0xb1/0x400 kernel/rcu/srcutree.c:1418
       elevator_disable+0xd4/0x4e0 block/elevator.c:661
       blk_mq_elv_switch_none block/blk-mq.c:4951 [inline]
       __blk_mq_update_nr_hw_queues block/blk-mq.c:5018 [inline]
       blk_mq_update_nr_hw_queues+0x5d3/0x1a30 block/blk-mq.c:5070
       nbd_start_device+0x163/0xab0 drivers/block/nbd.c:1476
       nbd_start_device_ioctl drivers/block/nbd.c:1527 [inline]
       __nbd_ioctl drivers/block/nbd.c:1602 [inline]
       nbd_ioctl+0x5dc/0xf40 drivers/block/nbd.c:1642
       blkdev_ioctl+0x5d2/0x6f0 block/ioctl.c:693
       vfs_ioctl fs/ioctl.c:51 [inline]
       __do_sys_ioctl fs/ioctl.c:906 [inline]
       __se_sys_ioctl+0xf7/0x170 fs/ioctl.c:892
       do_syscall_x64 arch/x86/entry/common.c:52 [inline]
       do_syscall_64+0xf3/0x230 arch/x86/entry/common.c:83
       entry_SYSCALL_64_after_hwframe+0x77/0x7f

-> #1 (&q->sysfs_lock){+.+.}-{4:4}:
       lock_acquire+0x1ed/0x550 kernel/locking/lockdep.c:5851
       __mutex_lock_common kernel/locking/mutex.c:585 [inline]
       __mutex_lock+0x19c/0x1010 kernel/locking/mutex.c:730
       blk_mq_elv_switch_none block/blk-mq.c:4937 [inline]
       __blk_mq_update_nr_hw_queues block/blk-mq.c:5018 [inline]
       blk_mq_update_nr_hw_queues+0x388/0x1a30 block/blk-mq.c:5070
       nbd_start_device+0x163/0xab0 drivers/block/nbd.c:1476
       nbd_start_device_ioctl drivers/block/nbd.c:1527 [inline]
       __nbd_ioctl drivers/block/nbd.c:1602 [inline]
       nbd_ioctl+0x5dc/0xf40 drivers/block/nbd.c:1642
       blkdev_ioctl+0x5d2/0x6f0 block/ioctl.c:693
       vfs_ioctl fs/ioctl.c:51 [inline]
       __do_sys_ioctl fs/ioctl.c:906 [inline]
       __se_sys_ioctl+0xf7/0x170 fs/ioctl.c:892
       do_syscall_x64 arch/x86/entry/common.c:52 [inline]
       do_syscall_64+0xf3/0x230 arch/x86/entry/common.c:83
       entry_SYSCALL_64_after_hwframe+0x77/0x7f

-> #0 (&q->q_usage_counter(io)#54){++++}-{0:0}:
       check_prev_add kernel/locking/lockdep.c:3163 [inline]
       check_prevs_add kernel/locking/lockdep.c:3282 [inline]
       validate_chain+0x18ef/0x5920 kernel/locking/lockdep.c:3906
       __lock_acquire+0x1397/0x2100 kernel/locking/lockdep.c:5228
       lock_acquire+0x1ed/0x550 kernel/locking/lockdep.c:5851
       bio_queue_enter block/blk.h:77 [inline]
       blk_mq_submit_bio+0x14e1/0x25a0 block/blk-mq.c:3091
       __submit_bio+0x2cf/0x6a0 block/blk-core.c:628
       __submit_bio_noacct_mq block/blk-core.c:715 [inline]
       submit_bio_noacct_nocheck+0x4d3/0xe30 block/blk-core.c:744
       mpage_bio_submit_read fs/mpage.c:75 [inline]
       mpage_readahead+0x630/0x780 fs/mpage.c:377
       read_pages+0x17b/0x570 mm/readahead.c:161
       page_cache_ra_unbounded+0x708/0x820 mm/readahead.c:298
       do_page_cache_ra mm/readahead.c:328 [inline]
       force_page_cache_ra mm/readahead.c:357 [inline]
       page_cache_sync_ra+0x3e2/0xb00 mm/readahead.c:585
       filemap_get_pages+0x59a/0x1fb0 mm/filemap.c:2580
       filemap_read+0x464/0x1260 mm/filemap.c:2691
       blkdev_read_iter+0x31f/0x460 block/fops.c:796
       new_sync_read fs/read_write.c:484 [inline]
       vfs_read+0x977/0xb40 fs/read_write.c:565
       ksys_read+0x18f/0x2b0 fs/read_write.c:708
       do_syscall_x64 arch/x86/entry/common.c:52 [inline]
       do_syscall_64+0xf3/0x230 arch/x86/entry/common.c:83
       entry_SYSCALL_64_after_hwframe+0x77/0x7f

other info that might help us debug this:

Chain exists of:
  &q->q_usage_counter(io)#54 --> &mm->mmap_lock --> mapping.invalidate_lock#2

 Possible unsafe locking scenario:

       CPU0                    CPU1
       ----                    ----
  rlock(mapping.invalidate_lock#2);
                               lock(&mm->mmap_lock);
                               lock(mapping.invalidate_lock#2);
  rlock(&q->q_usage_counter(io)#54);

 *** DEADLOCK ***

1 lock held by udevd/5899:
 #0: ffff888023a6f0c0 (mapping.invalidate_lock#2){.+.+}-{4:4}, at: filemap_invalidate_lock_shared include/linux/fs.h:932 [inline]
 #0: ffff888023a6f0c0 (mapping.invalidate_lock#2){.+.+}-{4:4}, at: page_cache_ra_unbounded+0x156/0x820 mm/readahead.c:229

stack backtrace:
CPU: 1 UID: 0 PID: 5899 Comm: udevd Not tainted 6.14.0-rc4-syzkaller-00052-gac9c34d1e45a #0
Hardware name: Google Google Compute Engine/Google Compute Engine, BIOS Google 02/12/2025
Call Trace:
 <TASK>
 __dump_stack lib/dump_stack.c:94 [inline]
 dump_stack_lvl+0x241/0x360 lib/dump_stack.c:120
 print_circular_bug+0x13a/0x1b0 kernel/locking/lockdep.c:2076
 check_noncircular+0x36a/0x4a0 kernel/locking/lockdep.c:2208
 check_prev_add kernel/locking/lockdep.c:3163 [inline]
 check_prevs_add kernel/locking/lockdep.c:3282 [inline]
 validate_chain+0x18ef/0x5920 kernel/locking/lockdep.c:3906
 __lock_acquire+0x1397/0x2100 kernel/locking/lockdep.c:5228
 lock_acquire+0x1ed/0x550 kernel/locking/lockdep.c:5851
 bio_queue_enter block/blk.h:77 [inline]
 blk_mq_submit_bio+0x14e1/0x25a0 block/blk-mq.c:3091
 __submit_bio+0x2cf/0x6a0 block/blk-core.c:628
 __submit_bio_noacct_mq block/blk-core.c:715 [inline]
 submit_bio_noacct_nocheck+0x4d3/0xe30 block/blk-core.c:744
 mpage_bio_submit_read fs/mpage.c:75 [inline]
 mpage_readahead+0x630/0x780 fs/mpage.c:377
 read_pages+0x17b/0x570 mm/readahead.c:161
 page_cache_ra_unbounded+0x708/0x820 mm/readahead.c:298
 do_page_cache_ra mm/readahead.c:328 [inline]
 force_page_cache_ra mm/readahead.c:357 [inline]
 page_cache_sync_ra+0x3e2/0xb00 mm/readahead.c:585
 filemap_get_pages+0x59a/0x1fb0 mm/filemap.c:2580
 filemap_read+0x464/0x1260 mm/filemap.c:2691
 blkdev_read_iter+0x31f/0x460 block/fops.c:796
 new_sync_read fs/read_write.c:484 [inline]
 vfs_read+0x977/0xb40 fs/read_write.c:565
 ksys_read+0x18f/0x2b0 fs/read_write.c:708
 do_syscall_x64 arch/x86/entry/common.c:52 [inline]
 do_syscall_64+0xf3/0x230 arch/x86/entry/common.c:83
 entry_SYSCALL_64_after_hwframe+0x77/0x7f
RIP: 0033:0x7f8e94116b6a
Code: 00 3d 00 00 41 00 75 0d 50 48 8d 3d 2d 08 0a 00 e8 ea 7d 01 00 31 c0 e9 07 ff ff ff 64 8b 04 25 18 00 00 00 85 c0 75 1b 0f 05 <48> 3d 00 f0 ff ff 76 6c 48 8b 15 8f a2 0d 00 f7 d8 64 89 02 48 83
RSP: 002b:00007ffc4ec2de28 EFLAGS: 00000246 ORIG_RAX: 0000000000000000
RAX: ffffffffffffffda RBX: 00000007ffff0000 RCX: 00007f8e94116b6a
RDX: 0000000000000040 RSI: 0000563def0c8958 RDI: 0000000000000009
RBP: 0000000000000040 R08: 0000563def0c8930 R09: 0000000000000200
R10: 0000000000000015 R11: 0000000000000246 R12: 0000563def0c8930
R13: 0000563def0c8948 R14: 0000563def0bcad8 R15: 0000563def0bca80
 </TASK>