====================================================== WARNING: possible circular locking dependency detected 5.10.209 #1 Not tainted ------------------------------------------------------ syz-executor.3/23518 is trying to acquire lock: ffff88800dc54b78 ((work_completion)(&hdev->bg_scan_update)){+.+.}-{0:0}, at: __flush_work+0xdd/0xa90 kernel/workqueue.c:3050 but task is already holding lock: ffffffff85619668 (rfkill_global_mutex){+.+.}-{3:3}, at: rfkill_fop_write+0xff/0x4b0 net/rfkill/core.c:1232 which lock already depends on the new lock. the existing dependency chain (in reverse order) is: -> #4 (rfkill_global_mutex){+.+.}-{3:3}: __mutex_lock_common kernel/locking/mutex.c:968 [inline] __mutex_lock+0x13d/0x10b0 kernel/locking/mutex.c:1109 rfkill_register+0x36/0xa10 net/rfkill/core.c:1016 FAULT_INJECTION: forcing a failure. name fail_usercopy, interval 1, probability 0, space 0, times 0 hci_register_dev+0x42e/0xc00 net/bluetooth/hci_core.c:3773 __vhci_create_device+0x2c8/0x5c0 drivers/bluetooth/hci_vhci.c:129 CPU: 1 PID: 23514 Comm: syz-executor.4 Not tainted 5.10.209 #1 vhci_create_device drivers/bluetooth/hci_vhci.c:153 [inline] vhci_open_timeout+0x38/0x50 drivers/bluetooth/hci_vhci.c:310 process_one_work+0x9a9/0x14b0 kernel/workqueue.c:2282 Hardware name: QEMU Standard PC (i440FX + PIIX, 1996), BIOS 1.12.0-1 04/01/2014 worker_thread+0x61d/0x1310 kernel/workqueue.c:2428 kthread+0x38f/0x470 kernel/kthread.c:313 Call Trace: ret_from_fork+0x22/0x30 arch/x86/entry/entry_64.S:299 -> #3 __dump_stack lib/dump_stack.c:77 [inline] dump_stack+0x107/0x167 lib/dump_stack.c:118 (&data->open_mutex fail_dump lib/fault-inject.c:52 [inline] should_fail.cold+0x5/0xa lib/fault-inject.c:146 ){+.+.}-{3:3}: _copy_to_user+0x2e/0x180 lib/usercopy.c:36 __mutex_lock_common kernel/locking/mutex.c:968 [inline] __mutex_lock+0x13d/0x10b0 kernel/locking/mutex.c:1109 copy_to_user include/linux/uaccess.h:200 [inline] simple_read_from_buffer+0xcc/0x160 fs/libfs.c:729 vhci_send_frame+0x63/0xa0 drivers/bluetooth/hci_vhci.c:71 hci_send_frame+0x1b9/0x320 net/bluetooth/hci_core.c:4060 proc_fail_nth_read+0x198/0x230 fs/proc/base.c:1423 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 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 -> #2 ((work_completion)(&hdev->tx_work) ){+.+.}-{0:0}: vfs_read+0x228/0x580 fs/read_write.c:494 __flush_work+0x105/0xa90 kernel/workqueue.c:3053 hci_dev_do_close+0x131/0x1240 net/bluetooth/hci_core.c:1745 ksys_read+0x12d/0x260 fs/read_write.c:634 hci_unregister_dev+0x149/0x430 net/bluetooth/hci_core.c:3849 vhci_release+0x70/0xf0 drivers/bluetooth/hci_vhci.c:345 __fput+0x285/0x980 fs/file_table.c:281 task_work_run+0xe2/0x1a0 kernel/task_work.c:161 exit_task_work include/linux/task_work.h:32 [inline] do_exit+0xb6f/0x2600 kernel/exit.c:858 do_group_exit+0x125/0x310 kernel/exit.c:980 __do_sys_exit_group kernel/exit.c:991 [inline] __se_sys_exit_group kernel/exit.c:989 [inline] __x64_sys_exit_group+0x3a/0x50 kernel/exit.c:989 do_syscall_64+0x33/0x40 arch/x86/entry/common.c:46 do_syscall_64+0x33/0x40 arch/x86/entry/common.c:46 entry_SYSCALL_64_after_hwframe+0x62/0xc7 -> #1 entry_SYSCALL_64_after_hwframe+0x62/0xc7 (&hdev->req_lock RIP: 0033:0x7fc72f25c69c ){+.+.}-{3:3}: Code: ec 28 48 89 54 24 18 48 89 74 24 10 89 7c 24 08 e8 f9 fc ff ff 48 8b 54 24 18 48 8b 74 24 10 41 89 c0 8b 7c 24 08 31 c0 0f 05 <48> 3d 00 f0 ff ff 77 34 44 89 c7 48 89 44 24 08 e8 2f fd ff ff 48 __mutex_lock_common kernel/locking/mutex.c:968 [inline] __mutex_lock+0x13d/0x10b0 kernel/locking/mutex.c:1109 RSP: 002b:00007fc72c81f170 EFLAGS: 00000246 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 ORIG_RAX: 0000000000000000 worker_thread+0x61d/0x1310 kernel/workqueue.c:2428 kthread+0x38f/0x470 kernel/kthread.c:313 RAX: ffffffffffffffda RBX: 0000000000000034 RCX: 00007fc72f25c69c ret_from_fork+0x22/0x30 arch/x86/entry/entry_64.S:299 -> #0 RDX: 000000000000000f RSI: 00007fc72c81f1e0 RDI: 0000000000000003 ((work_completion)(&hdev->bg_scan_update) RBP: 00007fc72c81f1d0 R08: 0000000000000000 R09: 0000000000000000 ){+.+.}-{0:0}: R10: 0000000000000000 R11: 0000000000000246 R12: 0000000000000002 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 R13: 00007ffdc8b280ff R14: 00007fc72c81f300 R15: 0000000000022000 __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.3/23518: #0: ffffffff85619668 (rfkill_global_mutex){+.+.}-{3:3}, at: rfkill_fop_write+0xff/0x4b0 net/rfkill/core.c:1232 stack backtrace: CPU: 0 PID: 23518 Comm: syz-executor.3 Not tainted 5.10.209 #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: 0033:0x7f7858433b19 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:00007f78559a9188 EFLAGS: 00000246 ORIG_RAX: 0000000000000001 RAX: ffffffffffffffda RBX: 00007f7858546f60 RCX: 00007f7858433b19 RDX: 0000000000000008 RSI: 00000000200000c0 RDI: 0000000000000004 RBP: 00007f785848df6d R08: 0000000000000000 R09: 0000000000000000 R10: 0000000000000000 R11: 0000000000000246 R12: 0000000000000000 R13: 00007ffee3f8caff R14: 00007f78559a9300 R15: 0000000000022000 udc-core: couldn't find an available UDC or it's busy misc raw-gadget: fail, usb_gadget_probe_driver returned -19 ---------------- Code disassembly (best guess): 0: ec in (%dx),%al 1: 28 48 89 sub %cl,-0x77(%rax) 4: 54 push %rsp 5: 24 18 and $0x18,%al 7: 48 89 74 24 10 mov %rsi,0x10(%rsp) c: 89 7c 24 08 mov %edi,0x8(%rsp) 10: e8 f9 fc ff ff callq 0xfffffd0e 15: 48 8b 54 24 18 mov 0x18(%rsp),%rdx 1a: 48 8b 74 24 10 mov 0x10(%rsp),%rsi 1f: 41 89 c0 mov %eax,%r8d 22: 8b 7c 24 08 mov 0x8(%rsp),%edi 26: 31 c0 xor %eax,%eax 28: 0f 05 syscall * 2a: 48 3d 00 f0 ff ff cmp $0xfffffffffffff000,%rax <-- trapping instruction 30: 77 34 ja 0x66 32: 44 89 c7 mov %r8d,%edi 35: 48 89 44 24 08 mov %rax,0x8(%rsp) 3a: e8 2f fd ff ff callq 0xfffffd6e 3f: 48 rex.W