====================================================== WARNING: possible circular locking dependency detected 5.10.209 #1 Not tainted ------------------------------------------------------ syz-executor.5/10586 is trying to acquire lock: ffff888017eecb78 ((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}: FAULT_INJECTION: forcing a failure. name failslab, interval 1, probability 0, space 0, times 0 __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 CPU: 1 PID: 10596 Comm: syz-executor.7 Not tainted 5.10.209 #1 hci_register_dev+0x42e/0xc00 net/bluetooth/hci_core.c:3773 Hardware name: QEMU Standard PC (i440FX + PIIX, 1996), BIOS 1.12.0-1 04/01/2014 Call Trace: __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 __dump_stack lib/dump_stack.c:77 [inline] dump_stack+0x107/0x167 lib/dump_stack.c:118 process_one_work+0x9a9/0x14b0 kernel/workqueue.c:2282 fail_dump lib/fault-inject.c:52 [inline] should_fail.cold+0x5/0xa lib/fault-inject.c:146 worker_thread+0x61d/0x1310 kernel/workqueue.c:2428 kthread+0x38f/0x470 kernel/kthread.c:313 should_failslab+0x5/0x20 mm/slab_common.c:1193 ret_from_fork+0x22/0x30 arch/x86/entry/entry_64.S:299 slab_pre_alloc_hook mm/slab.h:515 [inline] slab_alloc_node mm/slub.c:2821 [inline] slab_alloc mm/slub.c:2904 [inline] kmem_cache_alloc+0x5b/0x310 mm/slub.c:2909 -> #3 kmem_cache_zalloc include/linux/slab.h:654 [inline] __kernfs_new_node+0xd4/0x860 fs/kernfs/dir.c:635 ( &data->open_mutex ){+.+.}-{3:3} : __mutex_lock_common kernel/locking/mutex.c:968 [inline] __mutex_lock+0x13d/0x10b0 kernel/locking/mutex.c:1109 kernfs_new_node+0x93/0x120 fs/kernfs/dir.c:699 vhci_send_frame+0x63/0xa0 drivers/bluetooth/hci_vhci.c:71 __kernfs_create_file+0x51/0x350 fs/kernfs/file.c:985 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 sysfs_add_file_mode_ns+0x221/0x560 fs/sysfs/file.c:306 process_one_work+0x9a9/0x14b0 kernel/workqueue.c:2282 create_files fs/sysfs/group.c:64 [inline] internal_create_group+0x324/0xb30 fs/sysfs/group.c:149 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 loop_sysfs_init drivers/block/loop.c:853 [inline] loop_configure+0x954/0x1480 drivers/block/loop.c:1159 ( lo_ioctl+0xa72/0x1760 drivers/block/loop.c:1687 (work_completion)(&hdev->tx_work) ){+.+.}-{0:0} : __flush_work+0x105/0xa90 kernel/workqueue.c:3053 hci_dev_do_close+0x131/0x1240 net/bluetooth/hci_core.c:1745 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 __blkdev_driver_ioctl block/ioctl.c:237 [inline] blkdev_ioctl+0x291/0x710 block/ioctl.c:632 __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 block_ioctl+0xf9/0x140 fs/block_dev.c:1893 entry_SYSCALL_64_after_hwframe+0x62/0xc7 -> #1 vfs_ioctl fs/ioctl.c:48 [inline] __do_sys_ioctl fs/ioctl.c:753 [inline] __se_sys_ioctl fs/ioctl.c:739 [inline] __x64_sys_ioctl+0x19a/0x210 fs/ioctl.c:739 ( do_syscall_64+0x33/0x40 arch/x86/entry/common.c:46 &hdev->req_lock entry_SYSCALL_64_after_hwframe+0x62/0xc7 ){+.+.}-{3:3} RIP: 0033:0x7f5f8e3208d7 : Code: 3c 1c 48 f7 d8 49 39 c4 72 b8 e8 a4 54 02 00 85 c0 78 bd 48 83 c4 08 4c 89 e0 5b 41 5c c3 0f 1f 44 00 00 b8 10 00 00 00 0f 05 <48> 3d 01 f0 ff ff 73 01 c3 48 c7 c1 bc ff ff ff f7 d8 64 89 01 48 __mutex_lock_common kernel/locking/mutex.c:968 [inline] __mutex_lock+0x13d/0x10b0 kernel/locking/mutex.c:1109 RSP: 002b:00007f5f8b895f48 EFLAGS: 00000246 ORIG_RAX: 0000000000000010 hci_req_sync net/bluetooth/hci_request.c:275 [inline] bg_scan_update+0x82/0x500 net/bluetooth/hci_request.c:2895 RAX: ffffffffffffffda RBX: 00007f5f8e36a970 RCX: 00007f5f8e3208d7 RDX: 0000000000000004 RSI: 0000000000004c00 RDI: 0000000000000005 process_one_work+0x9a9/0x14b0 kernel/workqueue.c:2282 RBP: 0000000000000005 R08: 0000000000000000 R09: ffffffffffffffff R10: 0000000000000000 R11: 0000000000000246 R12: 0000000000000004 worker_thread+0x61d/0x1310 kernel/workqueue.c:2428 R13: 0000000000000004 R14: 0000000020000520 R15: 0000000000000004 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.5/10586: #0: ffffffff85619668 (rfkill_global_mutex){+.+.}-{3:3}, at: rfkill_fop_write+0xff/0x4b0 net/rfkill/core.c:1232 stack backtrace: CPU: 0 PID: 10586 Comm: syz-executor.5 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: 0033:0x7f477ab56b19 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:00007f47780cc188 EFLAGS: 00000246 ORIG_RAX: 0000000000000001 RAX: ffffffffffffffda RBX: 00007f477ac69f60 RCX: 00007f477ab56b19 RDX: 0000000000000008 RSI: 00000000200000c0 RDI: 0000000000000006 RBP: 00007f477abb0f6d R08: 0000000000000000 R09: 0000000000000000 R10: 0000000000000000 R11: 0000000000000246 R12: 0000000000000000 R13: 00007ffdb2504b6f R14: 00007f47780cc300 R15: 0000000000022000 hpet: Lost 9 RTC interrupts [EXT4 FS bs=2048, gc=1, bpg=16384, ipg=32, mo=a802c018, mo2=0002] System zones: 0-7 EXT4-fs (loop7): mounted filesystem without journal. Opts: debug,,errors=continue EXT4-fs (sda): re-mounted. Opts: init_itable,grpjquota=,,errors=continue ---------------- Code disassembly (best guess): 0: 3c 1c cmp $0x1c,%al 2: 48 f7 d8 neg %rax 5: 49 39 c4 cmp %rax,%r12 8: 72 b8 jb 0xffffffc2 a: e8 a4 54 02 00 callq 0x254b3 f: 85 c0 test %eax,%eax 11: 78 bd js 0xffffffd0 13: 48 83 c4 08 add $0x8,%rsp 17: 4c 89 e0 mov %r12,%rax 1a: 5b pop %rbx 1b: 41 5c pop %r12 1d: c3 retq 1e: 0f 1f 44 00 00 nopl 0x0(%rax,%rax,1) 23: b8 10 00 00 00 mov $0x10,%eax 28: 0f 05 syscall * 2a: 48 3d 01 f0 ff ff cmp $0xfffffffffffff001,%rax <-- trapping instruction 30: 73 01 jae 0x33 32: c3 retq 33: 48 c7 c1 bc ff ff ff mov $0xffffffffffffffbc,%rcx 3a: f7 d8 neg %eax 3c: 64 89 01 mov %eax,%fs:(%rcx) 3f: 48 rex.W