====================================================== WARNING: possible circular locking dependency detected 5.10.206 #1 Not tainted ------------------------------------------------------ syz-executor.3/9421 is trying to acquire lock: ffff888017e74b78 ((work_completion)(&hdev->bg_scan_update)){+.+.}-{0:0}, at: __flush_work+0xdd/0xa90 kernel/workqueue.c:3050 but task is already holding lock: ffffffff856196a8 (rfkill_global_mutex){+.+.}-{3:3}, at: rfkill_fop_write+0xff/0x4b0 net/rfkill/core.c:1232 kmem_cache_create(9p-fcall-cache) failed with error -12 which lock already depends on the new lock. the existing dependency chain (in reverse order) is: -> #4 (rfkill_global_mutex){+.+.}-{3:3} CPU: 0 PID: 9402 Comm: syz-executor.0 Not tainted 5.10.206 #1 : Hardware name: QEMU Standard PC (i440FX + PIIX, 1996), BIOS 1.12.0-1 04/01/2014 __mutex_lock_common kernel/locking/mutex.c:968 [inline] __mutex_lock+0x13d/0x10b0 kernel/locking/mutex.c:1109 Call Trace: rfkill_register+0x36/0xa10 net/rfkill/core.c:1016 __dump_stack lib/dump_stack.c:77 [inline] dump_stack+0x107/0x167 lib/dump_stack.c:118 hci_register_dev+0x42e/0xc00 net/bluetooth/hci_core.c:3773 kmem_cache_create_usercopy.cold+0x17/0x65 mm/slab_common.c:371 __vhci_create_device+0x2c8/0x5c0 drivers/bluetooth/hci_vhci.c:129 vhci_create_device drivers/bluetooth/hci_vhci.c:153 [inline] vhci_open_timeout+0x38/0x50 drivers/bluetooth/hci_vhci.c:310 p9_client_create+0xc2b/0x11c0 net/9p/client.c:1063 process_one_work+0x9a9/0x14b0 kernel/workqueue.c:2282 worker_thread+0x61d/0x1310 kernel/workqueue.c:2428 kthread+0x38f/0x470 kernel/kthread.c:313 ret_from_fork+0x22/0x30 arch/x86/entry/entry_64.S:299 -> #3 v9fs_session_init+0x1dd/0x1680 fs/9p/v9fs.c:406 ( &data->open_mutex ){+.+.}-{3:3} : __mutex_lock_common kernel/locking/mutex.c:968 [inline] __mutex_lock+0x13d/0x10b0 kernel/locking/mutex.c:1109 vhci_send_frame+0x63/0xa0 drivers/bluetooth/hci_vhci.c:71 v9fs_mount+0x79/0x8f0 fs/9p/vfs_super.c:126 hci_send_frame+0x1b9/0x320 net/bluetooth/hci_core.c:4060 hci_sched_acl_pkt net/bluetooth/hci_core.c:4585 [inline] hci_sched_acl net/bluetooth/hci_core.c:4670 [inline] hci_tx_work+0x10af/0x1660 net/bluetooth/hci_core.c:4741 legacy_get_tree+0x105/0x220 fs/fs_context.c:593 process_one_work+0x9a9/0x14b0 kernel/workqueue.c:2282 vfs_get_tree+0x8e/0x300 fs/super.c:1559 worker_thread+0x61d/0x1310 kernel/workqueue.c:2428 do_new_mount fs/namespace.c:2899 [inline] path_mount+0x13be/0x20b0 fs/namespace.c:3229 kthread+0x38f/0x470 kernel/kthread.c:313 ret_from_fork+0x22/0x30 arch/x86/entry/entry_64.S:299 -> #2 ( (work_completion)(&hdev->tx_work) do_mount fs/namespace.c:3242 [inline] __do_sys_mount fs/namespace.c:3450 [inline] __se_sys_mount fs/namespace.c:3427 [inline] __x64_sys_mount+0x282/0x300 fs/namespace.c:3427 ){+.+.}-{0:0} : __flush_work+0x105/0xa90 kernel/workqueue.c:3053 hci_dev_do_close+0x131/0x1240 net/bluetooth/hci_core.c:1745 do_syscall_64+0x33/0x40 arch/x86/entry/common.c:46 hci_unregister_dev+0x149/0x430 net/bluetooth/hci_core.c:3849 entry_SYSCALL_64_after_hwframe+0x62/0xc7 vhci_release+0x70/0xf0 drivers/bluetooth/hci_vhci.c:345 RIP: 0033:0x7f4be83a8b19 __fput+0x285/0x980 fs/file_table.c:281 Code: ff ff c3 66 2e 0f 1f 84 00 00 00 00 00 0f 1f 40 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 bc ff ff ff f7 d8 64 89 01 48 task_work_run+0xe2/0x1a0 kernel/task_work.c:161 RSP: 002b:00007f4be591e188 EFLAGS: 00000246 exit_task_work include/linux/task_work.h:32 [inline] do_exit+0xb6f/0x2600 kernel/exit.c:858 ORIG_RAX: 00000000000000a5 do_group_exit+0x125/0x310 kernel/exit.c:980 RAX: ffffffffffffffda RBX: 00007f4be84bbf60 RCX: 00007f4be83a8b19 get_signal+0x4bc/0x22e0 kernel/signal.c:2751 RDX: 00000000200000c0 RSI: 0000000020000040 RDI: 0000000000000000 arch_do_signal_or_restart+0x2b7/0x1990 arch/x86/kernel/signal.c:805 RBP: 00007f4be591e1d0 R08: 0000000020000400 R09: 0000000000000000 handle_signal_work kernel/entry/common.c:145 [inline] exit_to_user_mode_loop kernel/entry/common.c:169 [inline] exit_to_user_mode_prepare+0x10f/0x190 kernel/entry/common.c:199 R10: 0000000000000000 R11: 0000000000000246 R12: 0000000000000002 syscall_exit_to_user_mode+0x38/0x1e0 kernel/entry/common.c:274 R13: 00007fff0850ee2f R14: 00007f4be591e300 R15: 0000000000022000 entry_SYSCALL_64_after_hwframe+0x62/0xc7 -> #1 (&hdev->req_lock){+.+.}-{3:3}: __mutex_lock_common kernel/locking/mutex.c:968 [inline] __mutex_lock+0x13d/0x10b0 kernel/locking/mutex.c:1109 hci_req_sync net/bluetooth/hci_request.c:275 [inline] bg_scan_update+0x82/0x500 net/bluetooth/hci_request.c:2895 process_one_work+0x9a9/0x14b0 kernel/workqueue.c:2282 worker_thread+0x61d/0x1310 kernel/workqueue.c:2428 kthread+0x38f/0x470 kernel/kthread.c:313 ret_from_fork+0x22/0x30 arch/x86/entry/entry_64.S:299 -> #0 ((work_completion)(&hdev->bg_scan_update)){+.+.}-{0:0}: check_prev_add kernel/locking/lockdep.c:2988 [inline] check_prevs_add kernel/locking/lockdep.c:3113 [inline] validate_chain kernel/locking/lockdep.c:3729 [inline] __lock_acquire+0x29e7/0x5b00 kernel/locking/lockdep.c:4955 lock_acquire kernel/locking/lockdep.c:5566 [inline] lock_acquire+0x197/0x470 kernel/locking/lockdep.c:5531 __flush_work+0x105/0xa90 kernel/workqueue.c:3053 __cancel_work_timer+0x368/0x4c0 kernel/workqueue.c:3144 hci_request_cancel_all+0x73/0x230 net/bluetooth/hci_request.c:3438 hci_dev_do_close+0xd9/0x1240 net/bluetooth/hci_core.c:1733 hci_rfkill_set_block+0x166/0x1a0 net/bluetooth/hci_core.c:2223 rfkill_set_block+0x1fd/0x540 net/rfkill/core.c:341 rfkill_fop_write+0x253/0x4b0 net/rfkill/core.c:1240 vfs_write+0x29a/0xa70 fs/read_write.c:603 ksys_write+0x1f6/0x260 fs/read_write.c:658 do_syscall_64+0x33/0x40 arch/x86/entry/common.c:46 entry_SYSCALL_64_after_hwframe+0x62/0xc7 other info that might help us debug this: Chain exists of: (work_completion)(&hdev->bg_scan_update) --> &data->open_mutex --> rfkill_global_mutex Possible unsafe locking scenario: CPU0 CPU1 ---- ---- lock(rfkill_global_mutex); lock(&data->open_mutex); lock(rfkill_global_mutex); lock((work_completion)(&hdev->bg_scan_update)); *** DEADLOCK *** 1 lock held by syz-executor.3/9421: #0: ffffffff856196a8 (rfkill_global_mutex){+.+.}-{3:3}, at: rfkill_fop_write+0xff/0x4b0 net/rfkill/core.c:1232 stack backtrace: CPU: 1 PID: 9421 Comm: syz-executor.3 Not tainted 5.10.206 #1 Hardware name: QEMU Standard PC (i440FX + PIIX, 1996), BIOS 1.12.0-1 04/01/2014 Call Trace: __dump_stack lib/dump_stack.c:77 [inline] dump_stack+0x107/0x167 lib/dump_stack.c:118 check_noncircular+0x263/0x2e0 kernel/locking/lockdep.c:2123 check_prev_add kernel/locking/lockdep.c:2988 [inline] check_prevs_add kernel/locking/lockdep.c:3113 [inline] validate_chain kernel/locking/lockdep.c:3729 [inline] __lock_acquire+0x29e7/0x5b00 kernel/locking/lockdep.c:4955 lock_acquire kernel/locking/lockdep.c:5566 [inline] lock_acquire+0x197/0x470 kernel/locking/lockdep.c:5531 __flush_work+0x105/0xa90 kernel/workqueue.c:3053 __cancel_work_timer+0x368/0x4c0 kernel/workqueue.c:3144 hci_request_cancel_all+0x73/0x230 net/bluetooth/hci_request.c:3438 hci_dev_do_close+0xd9/0x1240 net/bluetooth/hci_core.c:1733 hci_rfkill_set_block+0x166/0x1a0 net/bluetooth/hci_core.c:2223 rfkill_set_block+0x1fd/0x540 net/rfkill/core.c:341 rfkill_fop_write+0x253/0x4b0 net/rfkill/core.c:1240 vfs_write+0x29a/0xa70 fs/read_write.c:603 ksys_write+0x1f6/0x260 fs/read_write.c:658 do_syscall_64+0x33/0x40 arch/x86/entry/common.c:46 entry_SYSCALL_64_after_hwframe+0x62/0xc7 RIP: 0033:0x7fb9d47cdb19 Code: ff ff c3 66 2e 0f 1f 84 00 00 00 00 00 0f 1f 40 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 bc ff ff ff f7 d8 64 89 01 48 RSP: 002b:00007fb9d1d22188 EFLAGS: 00000246 ORIG_RAX: 0000000000000001 RAX: ffffffffffffffda RBX: 00007fb9d48e1020 RCX: 00007fb9d47cdb19 RDX: 0000000000000008 RSI: 00000000200000c0 RDI: 0000000000000006 RBP: 00007fb9d4827f6d R08: 0000000000000000 R09: 0000000000000000 R10: 0000000000000000 R11: 0000000000000246 R12: 0000000000000000 R13: 00007ffec6d3105f R14: 00007fb9d1d22300 R15: 0000000000022000 ---------------- Code disassembly (best guess), 1 bytes skipped: 0: ff c3 inc %ebx 2: 66 2e 0f 1f 84 00 00 nopw %cs:0x0(%rax,%rax,1) 9: 00 00 00 c: 0f 1f 40 00 nopl 0x0(%rax) 10: 48 89 f8 mov %rdi,%rax 13: 48 89 f7 mov %rsi,%rdi 16: 48 89 d6 mov %rdx,%rsi 19: 48 89 ca mov %rcx,%rdx 1c: 4d 89 c2 mov %r8,%r10 1f: 4d 89 c8 mov %r9,%r8 22: 4c 8b 4c 24 08 mov 0x8(%rsp),%r9 27: 0f 05 syscall * 29: 48 3d 01 f0 ff ff cmp $0xfffffffffffff001,%rax <-- trapping instruction 2f: 73 01 jae 0x32 31: c3 retq 32: 48 c7 c1 bc ff ff ff mov $0xffffffffffffffbc,%rcx 39: f7 d8 neg %eax 3b: 64 89 01 mov %eax,%fs:(%rcx) 3e: 48 rex.W