====================================================== WARNING: possible circular locking dependency detected 6.12.0-next-20241122-syzkaller #0 Not tainted ------------------------------------------------------ kworker/u8:5/1094 is trying to acquire lock: ffff88802535e7a8 (&q->sysfs_lock){+.+.}-{4:4}, at: blk_unregister_queue+0x134/0x200 block/blk-sysfs.c:867 but task is already holding lock: ffff88802535e838 (&q->sysfs_dir_lock){+.+.}-{4:4}, at: blk_unregister_queue+0xe5/0x200 block/blk-sysfs.c:858 which lock already depends on the new lock. the existing dependency chain (in reverse order) is: -> #5 (&q->sysfs_dir_lock){+.+.}-{4:4}: lock_acquire+0x1ed/0x550 kernel/locking/lockdep.c:5849 __mutex_lock_common kernel/locking/mutex.c:585 [inline] __mutex_lock+0x1ac/0xee0 kernel/locking/mutex.c:735 blk_mq_sysfs_unregister_hctxs+0xaa/0x300 block/blk-mq-sysfs.c:278 __blk_mq_update_nr_hw_queues block/blk-mq.c:4929 [inline] blk_mq_update_nr_hw_queues+0x6cc/0x1ae0 block/blk-mq.c:4984 nbd_start_device+0x16c/0xaa0 drivers/block/nbd.c:1413 nbd_start_device_ioctl drivers/block/nbd.c:1464 [inline] __nbd_ioctl drivers/block/nbd.c:1539 [inline] nbd_ioctl+0x5dc/0xf40 drivers/block/nbd.c:1579 blkdev_ioctl+0x57d/0x6a0 block/ioctl.c:693 vfs_ioctl fs/ioctl.c:51 [inline] __do_sys_ioctl fs/ioctl.c:906 [inline] __se_sys_ioctl+0xf5/0x170 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 -> #4 (&q->q_usage_counter(io)#49){++++}-{0:0}: lock_acquire+0x1ed/0x550 kernel/locking/lockdep.c:5849 bio_queue_enter block/blk.h:75 [inline] blk_mq_submit_bio+0x1536/0x23a0 block/blk-mq.c:3092 __submit_bio+0x2c6/0x560 block/blk-core.c:629 __submit_bio_noacct_mq block/blk-core.c:710 [inline] submit_bio_noacct_nocheck+0x4d3/0xe30 block/blk-core.c:739 submit_bh fs/buffer.c:2819 [inline] block_read_full_folio+0x93b/0xcd0 fs/buffer.c:2446 filemap_read_folio+0x14b/0x630 mm/filemap.c:2366 filemap_update_page mm/filemap.c:2450 [inline] filemap_get_pages+0x17af/0x2540 mm/filemap.c:2571 filemap_read+0x45c/0xf50 mm/filemap.c:2646 blkdev_read_iter+0x2d8/0x430 block/fops.c:767 new_sync_read fs/read_write.c:484 [inline] vfs_read+0x991/0xb70 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 -> #3 (mapping.invalidate_lock#2){.+.+}-{4:4}: lock_acquire+0x1ed/0x550 kernel/locking/lockdep.c:5849 down_read+0xb1/0xa40 kernel/locking/rwsem.c:1524 filemap_invalidate_lock_shared include/linux/fs.h:873 [inline] filemap_fault+0xd54/0x1950 mm/filemap.c:3351 __do_fault+0x135/0x460 mm/memory.c:4907 do_read_fault mm/memory.c:5322 [inline] do_fault mm/memory.c:5456 [inline] do_pte_missing mm/memory.c:3979 [inline] handle_pte_fault+0x3c01/0x66b0 mm/memory.c:5801 __handle_mm_fault mm/memory.c:5944 [inline] handle_mm_fault+0x1106/0x1bb0 mm/memory.c:6112 do_user_addr_fault arch/x86/mm/fault.c:1389 [inline] handle_page_fault arch/x86/mm/fault.c:1481 [inline] exc_page_fault+0x2b9/0x8c0 arch/x86/mm/fault.c:1539 asm_exc_page_fault+0x26/0x30 arch/x86/include/asm/idtentry.h:623 iovec_from_user+0xfb/0x240 lib/iov_iter.c:1411 process_vm_rw+0x2d9/0xc50 mm/process_vm_access.c:278 __do_sys_process_vm_readv mm/process_vm_access.c:296 [inline] __se_sys_process_vm_readv mm/process_vm_access.c:292 [inline] __x64_sys_process_vm_readv+0xe0/0x100 mm/process_vm_access.c:292 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 (&mm->mmap_lock){++++}-{4:4}: lock_acquire+0x1ed/0x550 kernel/locking/lockdep.c:5849 __might_fault+0xc6/0x120 mm/memory.c:6751 _inline_copy_from_user include/linux/uaccess.h:162 [inline] _copy_from_user+0x2a/0xc0 lib/usercopy.c:18 copy_from_user include/linux/uaccess.h:212 [inline] __blk_trace_setup kernel/trace/blktrace.c:626 [inline] blk_trace_ioctl+0x1ad/0x9a0 kernel/trace/blktrace.c:740 blkdev_ioctl+0x40c/0x6a0 block/ioctl.c:682 vfs_ioctl fs/ioctl.c:51 [inline] __do_sys_ioctl fs/ioctl.c:906 [inline] __se_sys_ioctl+0xf5/0x170 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->debugfs_mutex){+.+.}-{4:4}: lock_acquire+0x1ed/0x550 kernel/locking/lockdep.c:5849 __mutex_lock_common kernel/locking/mutex.c:585 [inline] __mutex_lock+0x1ac/0xee0 kernel/locking/mutex.c:735 blk_register_queue+0x15a/0x400 block/blk-sysfs.c:774 add_disk_fwnode+0x648/0xf80 block/genhd.c:493 add_disk include/linux/blkdev.h:755 [inline] brd_alloc+0x547/0x790 drivers/block/brd.c:399 brd_init+0x126/0x1b0 drivers/block/brd.c:479 do_one_initcall+0x248/0x880 init/main.c:1266 do_initcall_level+0x157/0x210 init/main.c:1328 do_initcalls+0x3f/0x80 init/main.c:1344 kernel_init_freeable+0x435/0x5d0 init/main.c:1577 kernel_init+0x1d/0x2b0 init/main.c:1466 ret_from_fork+0x4b/0x80 arch/x86/kernel/process.c:147 ret_from_fork_asm+0x1a/0x30 arch/x86/entry/entry_64.S:244 -> #0 (&q->sysfs_lock){+.+.}-{4:4}: check_prev_add kernel/locking/lockdep.c:3161 [inline] check_prevs_add kernel/locking/lockdep.c:3280 [inline] validate_chain+0x18ef/0x5920 kernel/locking/lockdep.c:3904 __lock_acquire+0x1397/0x2100 kernel/locking/lockdep.c:5226 lock_acquire+0x1ed/0x550 kernel/locking/lockdep.c:5849 __mutex_lock_common kernel/locking/mutex.c:585 [inline] __mutex_lock+0x1ac/0xee0 kernel/locking/mutex.c:735 blk_unregister_queue+0x134/0x200 block/blk-sysfs.c:867 del_gendisk+0x419/0x920 block/genhd.c:710 nbd_dev_remove drivers/block/nbd.c:264 [inline] nbd_dev_remove_work+0x47/0xe0 drivers/block/nbd.c:280 process_one_work kernel/workqueue.c:3229 [inline] process_scheduled_works+0xa63/0x1850 kernel/workqueue.c:3310 worker_thread+0x870/0xd30 kernel/workqueue.c:3391 kthread+0x2f0/0x390 kernel/kthread.c:389 ret_from_fork+0x4b/0x80 arch/x86/kernel/process.c:147 ret_from_fork_asm+0x1a/0x30 arch/x86/entry/entry_64.S:244 other info that might help us debug this: Chain exists of: &q->sysfs_lock --> &q->q_usage_counter(io)#49 --> &q->sysfs_dir_lock Possible unsafe locking scenario: CPU0 CPU1 ---- ---- lock(&q->sysfs_dir_lock); lock(&q->q_usage_counter(io)#49); lock(&q->sysfs_dir_lock); lock(&q->sysfs_lock); *** DEADLOCK *** 3 locks held by kworker/u8:5/1094: #0: ffff88802540a148 ((wq_completion)nbd-del){+.+.}-{0:0}, at: process_one_work kernel/workqueue.c:3204 [inline] #0: ffff88802540a148 ((wq_completion)nbd-del){+.+.}-{0:0}, at: process_scheduled_works+0x93b/0x1850 kernel/workqueue.c:3310 #1: ffffc900042e7d00 ((work_completion)(&nbd->remove_work)){+.+.}-{0:0}, at: process_one_work kernel/workqueue.c:3205 [inline] #1: ffffc900042e7d00 ((work_completion)(&nbd->remove_work)){+.+.}-{0:0}, at: process_scheduled_works+0x976/0x1850 kernel/workqueue.c:3310 #2: ffff88802535e838 (&q->sysfs_dir_lock){+.+.}-{4:4}, at: blk_unregister_queue+0xe5/0x200 block/blk-sysfs.c:858 stack backtrace: CPU: 1 UID: 0 PID: 1094 Comm: kworker/u8:5 Not tainted 6.12.0-next-20241122-syzkaller #0 Hardware name: Google Google Compute Engine/Google Compute Engine, BIOS Google 10/30/2024 Workqueue: nbd-del nbd_dev_remove_work Call Trace: __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:2074 check_noncircular+0x36a/0x4a0 kernel/locking/lockdep.c:2206 check_prev_add kernel/locking/lockdep.c:3161 [inline] check_prevs_add kernel/locking/lockdep.c:3280 [inline] validate_chain+0x18ef/0x5920 kernel/locking/lockdep.c:3904 __lock_acquire+0x1397/0x2100 kernel/locking/lockdep.c:5226 lock_acquire+0x1ed/0x550 kernel/locking/lockdep.c:5849 __mutex_lock_common kernel/locking/mutex.c:585 [inline] __mutex_lock+0x1ac/0xee0 kernel/locking/mutex.c:735 blk_unregister_queue+0x134/0x200 block/blk-sysfs.c:867 del_gendisk+0x419/0x920 block/genhd.c:710 nbd_dev_remove drivers/block/nbd.c:264 [inline] nbd_dev_remove_work+0x47/0xe0 drivers/block/nbd.c:280 process_one_work kernel/workqueue.c:3229 [inline] process_scheduled_works+0xa63/0x1850 kernel/workqueue.c:3310 worker_thread+0x870/0xd30 kernel/workqueue.c:3391 kthread+0x2f0/0x390 kernel/kthread.c:389 ret_from_fork+0x4b/0x80 arch/x86/kernel/process.c:147 ret_from_fork_asm+0x1a/0x30 arch/x86/entry/entry_64.S:244 netdevsim netdevsim9 netdevsim3 (unregistering): unset [1, 0] type 2 family 0 port 6081 - 0 netdevsim netdevsim9 netdevsim2 (unregistering): unset [1, 0] type 2 family 0 port 6081 - 0 netdevsim netdevsim9 netdevsim1 (unregistering): unset [1, 0] type 2 family 0 port 6081 - 0 netdevsim netdevsim9 netdevsim0 (unregistering): unset [1, 0] type 2 family 0 port 6081 - 0 bridge_slave_1: left allmulticast mode bridge_slave_1: left promiscuous mode bridge0: port 2(bridge_slave_1) entered disabled state bridge_slave_0: left allmulticast mode bridge_slave_0: left promiscuous mode bridge0: port 1(bridge_slave_0) entered disabled state bridge_slave_1: left allmulticast mode bridge_slave_1: left promiscuous mode bridge0: port 2(bridge_slave_1) entered disabled state bridge_slave_0: left allmulticast mode bridge_slave_0: left promiscuous mode bridge0: port 1(bridge_slave_0) entered disabled state bridge_slave_1: left allmulticast mode bridge_slave_1: left promiscuous mode bridge0: port 2(bridge_slave_1) entered disabled state bridge_slave_0: left allmulticast mode bridge_slave_0: left promiscuous mode bridge0: port 1(bridge_slave_0) entered disabled state bond0 (unregistering): (slave bond_slave_0): Releasing backup interface bond0 (unregistering): (slave bond_slave_1): Releasing backup interface bond0 (unregistering): Released all slaves bond0 (unregistering): Released all slaves bond0 (unregistering): (slave bond_slave_0): Releasing backup interface bond0 (unregistering): (slave bond_slave_1): Releasing backup interface bond0 (unregistering): Released all slaves bond0 (unregistering): (slave bond_slave_0): Releasing backup interface bond0 (unregistering): (slave bond_slave_1): Releasing backup interface bond0 (unregistering): Released all slaves hsr_slave_0: left promiscuous mode hsr_slave_1: left promiscuous mode batman_adv: batadv0: Interface deactivated: batadv_slave_0 batman_adv: batadv0: Removing interface: batadv_slave_0 batman_adv: batadv0: Interface deactivated: batadv_slave_1 batman_adv: batadv0: Removing interface: batadv_slave_1 veth1_macvtap: left promiscuous mode veth0_macvtap: left promiscuous mode veth1_vlan: left promiscuous mode veth0_vlan: left promiscuous mode team0 (unregistering): Port device team_slave_1 removed team0 (unregistering): Port device team_slave_0 removed team0 (unregistering): Port device team_slave_1 removed team0 (unregistering): Port device team_slave_0 removed