do_syscall_64+0x33/0x40 arch/x86/entry/common.c:46 ====================================================== entry_SYSCALL_64_after_hwframe+0x67/0xd1 WARNING: possible circular locking dependency detected RIP: 0033:0x7f9bdb491b19 5.10.232 #1 Not tainted 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:00007f9bd8a07188 EFLAGS: 00000246 ORIG_RAX: 0000000000000001 syz-executor.1/5271 is trying to acquire lock: RAX: ffffffffffffffda RBX: 00007f9bdb5a4f60 RCX: 00007f9bdb491b19 ffff88800e85cae8 RDX: 0000000000000008 RSI: 0000000020000000 RDI: 0000000000000003 ( RBP: 00007f9bd8a071d0 R08: 0000000000000000 R09: 0000000000000000 R10: 0000000000000000 R11: 0000000000000246 R12: 0000000000000001 (work_completion)(&hdev->tx_work) R13: 00007ffc995d074f R14: 00007f9bd8a07300 R15: 0000000000022000 ){+.+.}-{0:0}, at: __flush_work+0xdd/0xa90 kernel/workqueue.c:3050 but task is already holding lock: ffff88800e85cf40 (&hdev->req_lock){+.+.}-{3:3}, at: hci_dev_do_close+0xef/0x1240 net/bluetooth/hci_core.c:1734 which lock already depends on the new lock. the existing dependency chain (in reverse order) is: -> #3 (&hdev->req_lock){+.+.}-{3:3}: __mutex_lock_common kernel/locking/mutex.c:968 [inline] __mutex_lock+0x13d/0x10b0 kernel/locking/mutex.c:1109 hci_dev_do_close+0xef/0x1240 net/bluetooth/hci_core.c:1734 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+0x40f/0x4b0 net/rfkill/core.c:1248 vfs_write+0x29a/0xb10 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+0x67/0xd1 -> #2 (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 hci_register_dev+0x42e/0xc00 net/bluetooth/hci_core.c:3774 __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 process_one_work+0x9a9/0x14b0 kernel/workqueue.c:2282 worker_thread+0x61d/0x1310 kernel/workqueue.c:2428 kthread+0x38f/0x470 kernel/kthread.c:328 ret_from_fork+0x22/0x30 arch/x86/entry/entry_64.S:298 -> #1 (&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 hci_send_frame+0x1b9/0x320 net/bluetooth/hci_core.c:4065 hci_sched_acl_pkt net/bluetooth/hci_core.c:4590 [inline] hci_sched_acl net/bluetooth/hci_core.c:4675 [inline] hci_tx_work+0xfb4/0x15d0 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:328 ret_from_fork+0x22/0x30 arch/x86/entry/entry_64.S:298 -> #0 ((work_completion)(&hdev->tx_work)){+.+.}-{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 hci_dev_do_close+0x131/0x1240 net/bluetooth/hci_core.c:1745 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+0x40f/0x4b0 net/rfkill/core.c:1248 vfs_write+0x29a/0xb10 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+0x67/0xd1 other info that might help us debug this: Chain exists of: (work_completion)(&hdev->tx_work) --> rfkill_global_mutex --> &hdev->req_lock Possible unsafe locking scenario: CPU0 CPU1 ---- ---- lock(&hdev->req_lock); lock(rfkill_global_mutex); lock(&hdev->req_lock); lock((work_completion)(&hdev->tx_work)); *** DEADLOCK *** 2 locks held by syz-executor.1/5271: #0: ffffffff8561e1c8 (rfkill_global_mutex){+.+.}-{3:3}, at: rfkill_fop_write+0xff/0x4b0 net/rfkill/core.c:1232 #1: ffff88800e85cf40 (&hdev->req_lock){+.+.}-{3:3}, at: hci_dev_do_close+0xef/0x1240 net/bluetooth/hci_core.c:1734 stack backtrace: CPU: 1 PID: 5271 Comm: syz-executor.1 Not tainted 5.10.232 #1 Hardware name: QEMU Standard PC (i440FX + PIIX, 1996), BIOS 1.12.0-1 04/01/2014 FAULT_INJECTION: forcing a failure. name fail_usercopy, interval 1, probability 0, space 0, times 0 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 hci_dev_do_close+0x131/0x1240 net/bluetooth/hci_core.c:1745 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+0x40f/0x4b0 net/rfkill/core.c:1248 vfs_write+0x29a/0xb10 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+0x67/0xd1 RIP: 0033:0x7f12523ecb19 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:00007f124f962188 EFLAGS: 00000246 ORIG_RAX: 0000000000000001 RAX: ffffffffffffffda RBX: 00007f12524fff60 RCX: 00007f12523ecb19 RDX: 0000000000000008 RSI: 0000000020000000 RDI: 0000000000000003 RBP: 00007f1252446f6d R08: 0000000000000000 R09: 0000000000000000 R10: 0000000000000000 R11: 0000000000000246 R12: 0000000000000000 R13: 00007ffc9a00e5bf R14: 00007f124f962300 R15: 0000000000022000 CPU: 0 PID: 5279 Comm: syz-executor.0 Not tainted 5.10.232 #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 fail_dump lib/fault-inject.c:52 [inline] should_fail.cold+0x5/0xa lib/fault-inject.c:146 _copy_from_user+0x2e/0x1b0 lib/usercopy.c:15 copy_from_user include/linux/uaccess.h:192 [inline] kstrtouint_from_user+0xbd/0x220 lib/kstrtox.c:409 proc_fail_nth_write+0x78/0x220 fs/proc/base.c:1457 vfs_write+0x29a/0xb10 fs/read_write.c:603 ksys_write+0x12d/0x260 fs/read_write.c:658 do_syscall_64+0x33/0x40 arch/x86/entry/common.c:46 entry_SYSCALL_64_after_hwframe+0x67/0xd1 RIP: 0033:0x7fa1e97c05ff Code: 89 54 24 18 48 89 74 24 10 89 7c 24 08 e8 99 fd ff ff 48 8b 54 24 18 48 8b 74 24 10 41 89 c0 8b 7c 24 08 b8 01 00 00 00 0f 05 <48> 3d 00 f0 ff ff 77 31 44 89 c7 48 89 44 24 08 e8 cc fd ff ff 48 RSP: 002b:00007fa1e6d62170 EFLAGS: 00000293 ORIG_RAX: 0000000000000001 RAX: ffffffffffffffda RBX: 0000000000000000 RCX: 00007fa1e97c05ff RDX: 0000000000000001 RSI: 00007fa1e6d621e0 RDI: 0000000000000004 RBP: 00007fa1e6d621d0 R08: 0000000000000000 R09: 0000000000000000 R10: 0000000000000000 R11: 0000000000000293 R12: 0000000000000001 R13: 00007ffe68044f6f R14: 00007fa1e6d62300 R15: 0000000000022000 FAULT_INJECTION: forcing a failure. name fail_usercopy, interval 1, probability 0, space 0, times 0 CPU: 0 PID: 5285 Comm: syz-executor.2 Not tainted 5.10.232 #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 fail_dump lib/fault-inject.c:52 [inline] should_fail.cold+0x5/0xa lib/fault-inject.c:146 _copy_to_user+0x2e/0x180 lib/usercopy.c:36 copy_to_user include/linux/uaccess.h:200 [inline] simple_read_from_buffer+0xcc/0x160 fs/libfs.c:729 proc_fail_nth_read+0x198/0x230 fs/proc/base.c:1482 vfs_read+0x228/0x620 fs/read_write.c:494 ksys_read+0x12d/0x260 fs/read_write.c:634 do_syscall_64+0x33/0x40 arch/x86/entry/common.c:46 entry_SYSCALL_64_after_hwframe+0x67/0xd1 RIP: 0033:0x7fe71056369c 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 RSP: 002b:00007fe70db26170 EFLAGS: 00000246 ORIG_RAX: 0000000000000000 RAX: ffffffffffffffda RBX: 0000000000000008 RCX: 00007fe71056369c RDX: 000000000000000f RSI: 00007fe70db261e0 RDI: 0000000000000005 RBP: 00007fe70db261d0 R08: 0000000000000000 R09: 0000000000000000 R10: 0000000000000000 R11: 0000000000000246 R12: 0000000000000001 R13: 00007ffea64b16ff R14: 00007fe70db26300 R15: 0000000000022000 FAULT_INJECTION: forcing a failure. name failslab, interval 1, probability 0, space 0, times 1 CPU: 0 PID: 5287 Comm: syz-executor.5 Not tainted 5.10.232 #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 fail_dump lib/fault-inject.c:52 [inline] should_fail.cold+0x5/0xa lib/fault-inject.c:146 should_failslab+0x5/0x20 mm/slab_common.c:1200 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_trace+0x55/0x320 mm/slub.c:2921 kmalloc include/linux/slab.h:552 [inline] kzalloc include/linux/slab.h:664 [inline] kobject_uevent_env+0x22b/0xfd0 lib/kobject_uevent.c:539 rfkill_event net/rfkill/core.c:293 [inline] rfkill_event net/rfkill/core.c:288 [inline] rfkill_set_block+0x3bc/0x540 net/rfkill/core.c:364 rfkill_fop_write+0x40f/0x4b0 net/rfkill/core.c:1248 vfs_write+0x29a/0xb10 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+0x67/0xd1 RIP: 0033:0x7f9bdb491b19 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:00007f9bd8a07188 EFLAGS: 00000246 ORIG_RAX: 0000000000000001 RAX: ffffffffffffffda RBX: 00007f9bdb5a4f60 RCX: 00007f9bdb491b19 RDX: 0000000000000008 RSI: 0000000020000000 RDI: 0000000000000003 RBP: 00007f9bd8a071d0 R08: 0000000000000000 R09: 0000000000000000 R10: 0000000000000000 R11: 0000000000000246 R12: 0000000000000001 R13: 00007ffc995d074f R14: 00007f9bd8a07300 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