Extracting prog: 2m30.584589118s Minimizing prog: 10m0.091236477s Simplifying prog options: 3m51.746945977s Extracting C: 55.290014024s Simplifying C: 0s extracting reproducer from 30 programs first checking the prog from the crash report single: executing 1 programs separately with timeout 30s testing program (duration=30s, {Threaded:true Repeat:true RepeatTimes:0 Procs:5 Slowdown:1 Sandbox:none SandboxArg:0 Leak:false NetInjection:true NetDevices:true NetReset:true Cgroups:true BinfmtMisc:true CloseFDs:true KCSAN:false DevlinkPCI:false NicVF:false USB:true VhciInjection:true Wifi:true IEEE802154:true Sysctl:true Swap:true UseTmpDir:true HandleSegv:true Trace:false LegacyOptions:{Collide:false Fault:false FaultCall:0 FaultNth:0}}): openat$rfkill-syz_open_procfs-epoll_create1-epoll_ctl$EPOLL_CTL_ADD-ioctl$PTP_PIN_SETFUNC2-write$rfkill detailed listing: executing program 0: r0 = openat$rfkill(0xffffffffffffff9c, &(0x7f0000000040), 0x801, 0x0) r1 = syz_open_procfs(0x0, &(0x7f0000000280)='fd/3\x00') r2 = epoll_create1(0x0) epoll_ctl$EPOLL_CTL_ADD(r2, 0x1, r1, &(0x7f0000000240)={0x80000011}) ioctl$PTP_PIN_SETFUNC2(0xffffffffffffffff, 0x40603d10, 0x0) write$rfkill(r0, &(0x7f0000000080)={0x101, 0x0, 0x3, 0xfe}, 0x8) program crashed: possible deadlock in rfkill_fop_write single: successfully extracted reproducer found reproducer with 6 syscalls minimizing guilty program testing program (duration=45.1907439s, {Threaded:true Repeat:true RepeatTimes:0 Procs:5 Slowdown:1 Sandbox:none SandboxArg:0 Leak:false NetInjection:true NetDevices:true NetReset:true Cgroups:true BinfmtMisc:true CloseFDs:true KCSAN:false DevlinkPCI:false NicVF:false USB:true VhciInjection:true Wifi:true IEEE802154:true Sysctl:true Swap:true UseTmpDir:true HandleSegv:true Trace:false LegacyOptions:{Collide:false Fault:false FaultCall:0 FaultNth:0}}): openat$rfkill-syz_open_procfs-epoll_create1-epoll_ctl$EPOLL_CTL_ADD-ioctl$PTP_PIN_SETFUNC2 detailed listing: executing program 0: openat$rfkill(0xffffffffffffff9c, &(0x7f0000000040), 0x801, 0x0) r0 = syz_open_procfs(0x0, &(0x7f0000000280)='fd/3\x00') r1 = epoll_create1(0x0) epoll_ctl$EPOLL_CTL_ADD(r1, 0x1, r0, &(0x7f0000000240)={0x80000011}) ioctl$PTP_PIN_SETFUNC2(0xffffffffffffffff, 0x40603d10, 0x0) program did not crash testing program (duration=45.1907439s, {Threaded:true Repeat:true RepeatTimes:0 Procs:5 Slowdown:1 Sandbox:none SandboxArg:0 Leak:false NetInjection:true NetDevices:true NetReset:true Cgroups:true BinfmtMisc:true CloseFDs:true KCSAN:false DevlinkPCI:false NicVF:false USB:true VhciInjection:true Wifi:true IEEE802154:true Sysctl:true Swap:true UseTmpDir:true HandleSegv:true Trace:false LegacyOptions:{Collide:false Fault:false FaultCall:0 FaultNth:0}}): openat$rfkill-syz_open_procfs-epoll_create1-epoll_ctl$EPOLL_CTL_ADD-write$rfkill detailed listing: executing program 0: r0 = openat$rfkill(0xffffffffffffff9c, &(0x7f0000000040), 0x801, 0x0) r1 = syz_open_procfs(0x0, &(0x7f0000000280)='fd/3\x00') r2 = epoll_create1(0x0) epoll_ctl$EPOLL_CTL_ADD(r2, 0x1, r1, &(0x7f0000000240)={0x80000011}) write$rfkill(r0, &(0x7f0000000080)={0x101, 0x0, 0x3, 0xfe}, 0x8) program crashed: possible deadlock in rfkill_fop_write testing program (duration=45.1907439s, {Threaded:true Repeat:true RepeatTimes:0 Procs:5 Slowdown:1 Sandbox:none SandboxArg:0 Leak:false NetInjection:true NetDevices:true NetReset:true Cgroups:true BinfmtMisc:true CloseFDs:true KCSAN:false DevlinkPCI:false NicVF:false USB:true VhciInjection:true Wifi:true IEEE802154:true Sysctl:true Swap:true UseTmpDir:true HandleSegv:true Trace:false LegacyOptions:{Collide:false Fault:false FaultCall:0 FaultNth:0}}): openat$rfkill-syz_open_procfs-epoll_create1-write$rfkill detailed listing: executing program 0: r0 = openat$rfkill(0xffffffffffffff9c, &(0x7f0000000040), 0x801, 0x0) syz_open_procfs(0x0, &(0x7f0000000280)='fd/3\x00') epoll_create1(0x0) write$rfkill(r0, &(0x7f0000000080)={0x101, 0x0, 0x3, 0xfe}, 0x8) program crashed: possible deadlock in rfkill_fop_write testing program (duration=45.1907439s, {Threaded:true Repeat:true RepeatTimes:0 Procs:5 Slowdown:1 Sandbox:none SandboxArg:0 Leak:false NetInjection:true NetDevices:true NetReset:true Cgroups:true BinfmtMisc:true CloseFDs:true KCSAN:false DevlinkPCI:false NicVF:false USB:true VhciInjection:true Wifi:true IEEE802154:true Sysctl:true Swap:true UseTmpDir:true HandleSegv:true Trace:false LegacyOptions:{Collide:false Fault:false FaultCall:0 FaultNth:0}}): openat$rfkill-syz_open_procfs-write$rfkill detailed listing: executing program 0: r0 = openat$rfkill(0xffffffffffffff9c, &(0x7f0000000040), 0x801, 0x0) syz_open_procfs(0x0, &(0x7f0000000280)='fd/3\x00') write$rfkill(r0, &(0x7f0000000080)={0x101, 0x0, 0x3, 0xfe}, 0x8) program crashed: possible deadlock in rfkill_fop_write testing program (duration=45.1907439s, {Threaded:true Repeat:true RepeatTimes:0 Procs:5 Slowdown:1 Sandbox:none SandboxArg:0 Leak:false NetInjection:true NetDevices:true NetReset:true Cgroups:true BinfmtMisc:true CloseFDs:true KCSAN:false DevlinkPCI:false NicVF:false USB:true VhciInjection:true Wifi:true IEEE802154:true Sysctl:true Swap:true UseTmpDir:true HandleSegv:true Trace:false LegacyOptions:{Collide:false Fault:false FaultCall:0 FaultNth:0}}): openat$rfkill-write$rfkill detailed listing: executing program 0: r0 = openat$rfkill(0xffffffffffffff9c, &(0x7f0000000040), 0x801, 0x0) write$rfkill(r0, &(0x7f0000000080)={0x101, 0x0, 0x3, 0xfe}, 0x8) program crashed: possible deadlock in rfkill_fop_write testing program (duration=45.1907439s, {Threaded:true Repeat:true RepeatTimes:0 Procs:5 Slowdown:1 Sandbox:none SandboxArg:0 Leak:false NetInjection:true NetDevices:true NetReset:true Cgroups:true BinfmtMisc:true CloseFDs:true KCSAN:false DevlinkPCI:false NicVF:false USB:true VhciInjection:true Wifi:true IEEE802154:true Sysctl:true Swap:true UseTmpDir:true HandleSegv:true Trace:false LegacyOptions:{Collide:false Fault:false FaultCall:0 FaultNth:0}}): write$rfkill detailed listing: executing program 0: write$rfkill(0xffffffffffffffff, &(0x7f0000000080)={0x101, 0x0, 0x3, 0xfe}, 0x8) program did not crash testing program (duration=45.1907439s, {Threaded:true Repeat:true RepeatTimes:0 Procs:5 Slowdown:1 Sandbox:none SandboxArg:0 Leak:false NetInjection:true NetDevices:true NetReset:true Cgroups:true BinfmtMisc:true CloseFDs:true KCSAN:false DevlinkPCI:false NicVF:false USB:true VhciInjection:true Wifi:true IEEE802154:true Sysctl:true Swap:true UseTmpDir:true HandleSegv:true Trace:false LegacyOptions:{Collide:false Fault:false FaultCall:0 FaultNth:0}}): openat$rfkill-write$rfkill detailed listing: executing program 0: r0 = openat$rfkill(0xffffffffffffff9c, 0x0, 0x801, 0x0) write$rfkill(r0, &(0x7f0000000080)={0x101, 0x0, 0x3, 0xfe}, 0x8) program did not crash testing program (duration=45.1907439s, {Threaded:true Repeat:true RepeatTimes:0 Procs:5 Slowdown:1 Sandbox:none SandboxArg:0 Leak:false NetInjection:true NetDevices:true NetReset:true Cgroups:true BinfmtMisc:true CloseFDs:true KCSAN:false DevlinkPCI:false NicVF:false USB:true VhciInjection:true Wifi:true IEEE802154:true Sysctl:true Swap:true UseTmpDir:true HandleSegv:true Trace:false LegacyOptions:{Collide:false Fault:false FaultCall:0 FaultNth:0}}): openat$rfkill-write$rfkill detailed listing: executing program 0: r0 = openat$rfkill(0xffffffffffffff9c, &(0x7f0000000040), 0x801, 0x0) write$rfkill(r0, 0x0, 0x0) program did not crash extracting C reproducer testing compiled C program (duration=45.1907439s, {Threaded:true Repeat:true RepeatTimes:0 Procs:5 Slowdown:1 Sandbox:none SandboxArg:0 Leak:false NetInjection:true NetDevices:true NetReset:true Cgroups:true BinfmtMisc:true CloseFDs:true KCSAN:false DevlinkPCI:false NicVF:false USB:true VhciInjection:true Wifi:true IEEE802154:true Sysctl:true Swap:true UseTmpDir:true HandleSegv:true Trace:false LegacyOptions:{Collide:false Fault:false FaultCall:0 FaultNth:0}}): openat$rfkill-write$rfkill program crashed: possible deadlock in hci_dev_do_close a never seen crash title: possible deadlock in hci_dev_do_close, ignore simplifying guilty program options testing program (duration=45.1907439s, {Threaded:false Repeat:true RepeatTimes:0 Procs:5 Slowdown:1 Sandbox:none SandboxArg:0 Leak:false NetInjection:true NetDevices:true NetReset:true Cgroups:true BinfmtMisc:true CloseFDs:true KCSAN:false DevlinkPCI:false NicVF:false USB:true VhciInjection:true Wifi:true IEEE802154:true Sysctl:true Swap:true UseTmpDir:true HandleSegv:true Trace:false LegacyOptions:{Collide:false Fault:false FaultCall:0 FaultNth:0}}): openat$rfkill-write$rfkill detailed listing: executing program 0: r0 = openat$rfkill(0xffffffffffffff9c, &(0x7f0000000040), 0x801, 0x0) write$rfkill(r0, &(0x7f0000000080)={0x101, 0x0, 0x3, 0xfe}, 0x8) program crashed: possible deadlock in rfkill_fop_write extracting C reproducer testing compiled C program (duration=45.1907439s, {Threaded:false Repeat:true RepeatTimes:0 Procs:5 Slowdown:1 Sandbox:none SandboxArg:0 Leak:false NetInjection:true NetDevices:true NetReset:true Cgroups:true BinfmtMisc:true CloseFDs:true KCSAN:false DevlinkPCI:false NicVF:false USB:true VhciInjection:true Wifi:true IEEE802154:true Sysctl:true Swap:true UseTmpDir:true HandleSegv:true Trace:false LegacyOptions:{Collide:false Fault:false FaultCall:0 FaultNth:0}}): openat$rfkill-write$rfkill program crashed: possible deadlock in hci_dev_do_close a never seen crash title: possible deadlock in hci_dev_do_close, ignore testing program (duration=45.1907439s, {Threaded:false Repeat:false RepeatTimes:0 Procs:1 Slowdown:1 Sandbox:none SandboxArg:0 Leak:false NetInjection:true NetDevices:true NetReset:false Cgroups:false BinfmtMisc:true CloseFDs:true KCSAN:false DevlinkPCI:false NicVF:false USB:true VhciInjection:true Wifi:true IEEE802154:true Sysctl:true Swap:true UseTmpDir:true HandleSegv:true Trace:false LegacyOptions:{Collide:false Fault:false FaultCall:0 FaultNth:0}}): openat$rfkill-write$rfkill detailed listing: executing program 0: r0 = openat$rfkill(0xffffffffffffff9c, &(0x7f0000000040), 0x801, 0x0) write$rfkill(r0, &(0x7f0000000080)={0x101, 0x0, 0x3, 0xfe}, 0x8) program crashed: possible deadlock in rfkill_fop_write extracting C reproducer testing compiled C program (duration=45.1907439s, {Threaded:false Repeat:false RepeatTimes:0 Procs:1 Slowdown:1 Sandbox:none SandboxArg:0 Leak:false NetInjection:true NetDevices:true NetReset:false Cgroups:false BinfmtMisc:true CloseFDs:true KCSAN:false DevlinkPCI:false NicVF:false USB:true VhciInjection:true Wifi:true IEEE802154:true Sysctl:true Swap:true UseTmpDir:true HandleSegv:true Trace:false LegacyOptions:{Collide:false Fault:false FaultCall:0 FaultNth:0}}): openat$rfkill-write$rfkill program crashed: possible deadlock in hci_dev_do_close a never seen crash title: possible deadlock in hci_dev_do_close, ignore reproducing took 17m44.913028377s repro crashed as (corrupted=false): ====================================================== WARNING: possible circular locking dependency detected 5.15.185-syzkaller #0 Not tainted ------------------------------------------------------ syz.0.16/4318 is trying to acquire lock: ffff888024eacc28 ((work_completion)(&hdev->bg_scan_update)){+.+.}-{0:0}, at: __flush_work+0xc1/0x1b0 kernel/workqueue.c:3090 but task is already holding lock: ffffffff8d4b2748 (rfkill_global_mutex){+.+.}-{3:3}, at: rfkill_fop_write+0x19e/0x560 net/rfkill/core.c:1266 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+0x1eb/0x2390 kernel/locking/mutex.c:596 __mutex_lock kernel/locking/mutex.c:729 [inline] mutex_lock_nested+0x17/0x20 kernel/locking/mutex.c:743 rfkill_register+0x33/0x8a0 net/rfkill/core.c:1045 hci_register_dev+0x452/0x970 net/bluetooth/hci_core.c:3960 __vhci_create_device drivers/bluetooth/hci_vhci.c:129 [inline] vhci_create_device+0x32c/0x5c0 drivers/bluetooth/hci_vhci.c:153 vhci_get_user drivers/bluetooth/hci_vhci.c:210 [inline] vhci_write+0x391/0x450 drivers/bluetooth/hci_vhci.c:290 call_write_iter include/linux/fs.h:2172 [inline] new_sync_write fs/read_write.c:507 [inline] vfs_write+0x712/0xd00 fs/read_write.c:594 ksys_write+0x14d/0x250 fs/read_write.c:647 do_syscall_x64 arch/x86/entry/common.c:50 [inline] do_syscall_64+0x4c/0xa0 arch/x86/entry/common.c:80 entry_SYSCALL_64_after_hwframe+0x66/0xd0 -> #3 (&data->open_mutex){+.+.}-{3:3}: __mutex_lock_common+0x1eb/0x2390 kernel/locking/mutex.c:596 __mutex_lock kernel/locking/mutex.c:729 [inline] mutex_lock_nested+0x17/0x20 kernel/locking/mutex.c:743 vhci_send_frame+0x88/0x100 drivers/bluetooth/hci_vhci.c:71 hci_send_frame+0x1a9/0x2e0 net/bluetooth/hci_core.c:4256 hci_sched_acl_pkt net/bluetooth/hci_core.c:4781 [inline] hci_sched_acl net/bluetooth/hci_core.c:4866 [inline] hci_tx_work+0x9f9/0x1710 net/bluetooth/hci_core.c:4932 process_one_work+0x863/0x1000 kernel/workqueue.c:2310 worker_thread+0xaa8/0x12a0 kernel/workqueue.c:2457 kthread+0x436/0x520 kernel/kthread.c:334 ret_from_fork+0x1f/0x30 arch/x86/entry/entry_64.S:287 -> #2 ((work_completion)(&hdev->tx_work)){+.+.}-{0:0}: __flush_work+0xdd/0x1b0 kernel/workqueue.c:3090 hci_dev_do_close+0x1e7/0x1030 net/bluetooth/hci_core.c:1756 hci_unregister_dev+0x2d7/0x580 net/bluetooth/hci_core.c:4040 vhci_release+0x73/0xc0 drivers/bluetooth/hci_vhci.c:345 __fput+0x234/0x930 fs/file_table.c:311 task_work_run+0x125/0x1a0 kernel/task_work.c:188 exit_task_work include/linux/task_work.h:33 [inline] do_exit+0x616/0x20a0 kernel/exit.c:874 do_group_exit+0x12e/0x300 kernel/exit.c:996 get_signal+0x6ca/0x12c0 kernel/signal.c:2900 arch_do_signal_or_restart+0xc1/0x1300 arch/x86/kernel/signal.c:867 handle_signal_work kernel/entry/common.c:154 [inline] exit_to_user_mode_loop+0x9e/0x130 kernel/entry/common.c:178 exit_to_user_mode_prepare+0xb1/0x140 kernel/entry/common.c:214 __syscall_exit_to_user_mode_work kernel/entry/common.c:296 [inline] syscall_exit_to_user_mode+0x16/0x40 kernel/entry/common.c:307 do_syscall_64+0x58/0xa0 arch/x86/entry/common.c:86 entry_SYSCALL_64_after_hwframe+0x66/0xd0 -> #1 (&hdev->req_lock){+.+.}-{3:3}: __mutex_lock_common+0x1eb/0x2390 kernel/locking/mutex.c:596 __mutex_lock kernel/locking/mutex.c:729 [inline] mutex_lock_nested+0x17/0x20 kernel/locking/mutex.c:743 hci_req_sync net/bluetooth/hci_request.c:278 [inline] bg_scan_update+0x44/0x3b0 net/bluetooth/hci_request.c:2952 process_one_work+0x863/0x1000 kernel/workqueue.c:2310 worker_thread+0xaa8/0x12a0 kernel/workqueue.c:2457 kthread+0x436/0x520 kernel/kthread.c:334 ret_from_fork+0x1f/0x30 arch/x86/entry/entry_64.S:287 -> #0 ((work_completion)(&hdev->bg_scan_update)){+.+.}-{0:0}: check_prev_add kernel/locking/lockdep.c:3053 [inline] check_prevs_add kernel/locking/lockdep.c:3172 [inline] validate_chain kernel/locking/lockdep.c:3788 [inline] __lock_acquire+0x2c33/0x7c60 kernel/locking/lockdep.c:5012 lock_acquire+0x197/0x3f0 kernel/locking/lockdep.c:5623 __flush_work+0xdd/0x1b0 kernel/workqueue.c:3090 __cancel_work_timer+0x3ac/0x520 kernel/workqueue.c:3181 hci_request_cancel_all+0xcc/0x300 net/bluetooth/hci_request.c:3522 hci_dev_do_close+0x4e/0x1030 net/bluetooth/hci_core.c:1736 hci_rfkill_set_block+0x10a/0x190 net/bluetooth/hci_core.c:2235 rfkill_set_block+0x1c6/0x420 net/rfkill/core.c:345 rfkill_fop_write+0x458/0x560 net/rfkill/core.c:1274 vfs_write+0x300/0xd00 fs/read_write.c:592 ksys_write+0x14d/0x250 fs/read_write.c:647 do_syscall_x64 arch/x86/entry/common.c:50 [inline] do_syscall_64+0x4c/0xa0 arch/x86/entry/common.c:80 entry_SYSCALL_64_after_hwframe+0x66/0xd0 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.0.16/4318: #0: ffffffff8d4b2748 (rfkill_global_mutex){+.+.}-{3:3}, at: rfkill_fop_write+0x19e/0x560 net/rfkill/core.c:1266 stack backtrace: CPU: 0 PID: 4318 Comm: syz.0.16 Not tainted 5.15.185-syzkaller #0 Hardware name: Google Google Compute Engine/Google Compute Engine, BIOS Google 05/07/2025 Call Trace: dump_stack_lvl+0x168/0x230 lib/dump_stack.c:106 check_noncircular+0x274/0x310 kernel/locking/lockdep.c:2133 check_prev_add kernel/locking/lockdep.c:3053 [inline] check_prevs_add kernel/locking/lockdep.c:3172 [inline] validate_chain kernel/locking/lockdep.c:3788 [inline] __lock_acquire+0x2c33/0x7c60 kernel/locking/lockdep.c:5012 lock_acquire+0x197/0x3f0 kernel/locking/lockdep.c:5623 __flush_work+0xdd/0x1b0 kernel/workqueue.c:3090 __cancel_work_timer+0x3ac/0x520 kernel/workqueue.c:3181 hci_request_cancel_all+0xcc/0x300 net/bluetooth/hci_request.c:3522 hci_dev_do_close+0x4e/0x1030 net/bluetooth/hci_core.c:1736 hci_rfkill_set_block+0x10a/0x190 net/bluetooth/hci_core.c:2235 rfkill_set_block+0x1c6/0x420 net/rfkill/core.c:345 rfkill_fop_write+0x458/0x560 net/rfkill/core.c:1274 vfs_write+0x300/0xd00 fs/read_write.c:592 ksys_write+0x14d/0x250 fs/read_write.c:647 do_syscall_x64 arch/x86/entry/common.c:50 [inline] do_syscall_64+0x4c/0xa0 arch/x86/entry/common.c:80 entry_SYSCALL_64_after_hwframe+0x66/0xd0 RIP: 0033:0x7f61b342c929 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 a8 ff ff ff f7 d8 64 89 01 48 RSP: 002b:00007ffece7d16a8 EFLAGS: 00000246 ORIG_RAX: 0000000000000001 RAX: ffffffffffffffda RBX: 00007f61b3653fa0 RCX: 00007f61b342c929 RDX: 0000000000000008 RSI: 0000200000000080 RDI: 0000000000000003 RBP: 00007f61b34aeb39 R08: 0000000000000000 R09: 0000000000000000 R10: 0000000000000000 R11: 0000000000000246 R12: 0000000000000000 R13: 00007f61b3653fa0 R14: 00007f61b3653fa0 R15: 0000000000000003 final repro crashed as (corrupted=false): ====================================================== WARNING: possible circular locking dependency detected 5.15.185-syzkaller #0 Not tainted ------------------------------------------------------ syz.0.16/4318 is trying to acquire lock: ffff888024eacc28 ((work_completion)(&hdev->bg_scan_update)){+.+.}-{0:0}, at: __flush_work+0xc1/0x1b0 kernel/workqueue.c:3090 but task is already holding lock: ffffffff8d4b2748 (rfkill_global_mutex){+.+.}-{3:3}, at: rfkill_fop_write+0x19e/0x560 net/rfkill/core.c:1266 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+0x1eb/0x2390 kernel/locking/mutex.c:596 __mutex_lock kernel/locking/mutex.c:729 [inline] mutex_lock_nested+0x17/0x20 kernel/locking/mutex.c:743 rfkill_register+0x33/0x8a0 net/rfkill/core.c:1045 hci_register_dev+0x452/0x970 net/bluetooth/hci_core.c:3960 __vhci_create_device drivers/bluetooth/hci_vhci.c:129 [inline] vhci_create_device+0x32c/0x5c0 drivers/bluetooth/hci_vhci.c:153 vhci_get_user drivers/bluetooth/hci_vhci.c:210 [inline] vhci_write+0x391/0x450 drivers/bluetooth/hci_vhci.c:290 call_write_iter include/linux/fs.h:2172 [inline] new_sync_write fs/read_write.c:507 [inline] vfs_write+0x712/0xd00 fs/read_write.c:594 ksys_write+0x14d/0x250 fs/read_write.c:647 do_syscall_x64 arch/x86/entry/common.c:50 [inline] do_syscall_64+0x4c/0xa0 arch/x86/entry/common.c:80 entry_SYSCALL_64_after_hwframe+0x66/0xd0 -> #3 (&data->open_mutex){+.+.}-{3:3}: __mutex_lock_common+0x1eb/0x2390 kernel/locking/mutex.c:596 __mutex_lock kernel/locking/mutex.c:729 [inline] mutex_lock_nested+0x17/0x20 kernel/locking/mutex.c:743 vhci_send_frame+0x88/0x100 drivers/bluetooth/hci_vhci.c:71 hci_send_frame+0x1a9/0x2e0 net/bluetooth/hci_core.c:4256 hci_sched_acl_pkt net/bluetooth/hci_core.c:4781 [inline] hci_sched_acl net/bluetooth/hci_core.c:4866 [inline] hci_tx_work+0x9f9/0x1710 net/bluetooth/hci_core.c:4932 process_one_work+0x863/0x1000 kernel/workqueue.c:2310 worker_thread+0xaa8/0x12a0 kernel/workqueue.c:2457 kthread+0x436/0x520 kernel/kthread.c:334 ret_from_fork+0x1f/0x30 arch/x86/entry/entry_64.S:287 -> #2 ((work_completion)(&hdev->tx_work)){+.+.}-{0:0}: __flush_work+0xdd/0x1b0 kernel/workqueue.c:3090 hci_dev_do_close+0x1e7/0x1030 net/bluetooth/hci_core.c:1756 hci_unregister_dev+0x2d7/0x580 net/bluetooth/hci_core.c:4040 vhci_release+0x73/0xc0 drivers/bluetooth/hci_vhci.c:345 __fput+0x234/0x930 fs/file_table.c:311 task_work_run+0x125/0x1a0 kernel/task_work.c:188 exit_task_work include/linux/task_work.h:33 [inline] do_exit+0x616/0x20a0 kernel/exit.c:874 do_group_exit+0x12e/0x300 kernel/exit.c:996 get_signal+0x6ca/0x12c0 kernel/signal.c:2900 arch_do_signal_or_restart+0xc1/0x1300 arch/x86/kernel/signal.c:867 handle_signal_work kernel/entry/common.c:154 [inline] exit_to_user_mode_loop+0x9e/0x130 kernel/entry/common.c:178 exit_to_user_mode_prepare+0xb1/0x140 kernel/entry/common.c:214 __syscall_exit_to_user_mode_work kernel/entry/common.c:296 [inline] syscall_exit_to_user_mode+0x16/0x40 kernel/entry/common.c:307 do_syscall_64+0x58/0xa0 arch/x86/entry/common.c:86 entry_SYSCALL_64_after_hwframe+0x66/0xd0 -> #1 (&hdev->req_lock){+.+.}-{3:3}: __mutex_lock_common+0x1eb/0x2390 kernel/locking/mutex.c:596 __mutex_lock kernel/locking/mutex.c:729 [inline] mutex_lock_nested+0x17/0x20 kernel/locking/mutex.c:743 hci_req_sync net/bluetooth/hci_request.c:278 [inline] bg_scan_update+0x44/0x3b0 net/bluetooth/hci_request.c:2952 process_one_work+0x863/0x1000 kernel/workqueue.c:2310 worker_thread+0xaa8/0x12a0 kernel/workqueue.c:2457 kthread+0x436/0x520 kernel/kthread.c:334 ret_from_fork+0x1f/0x30 arch/x86/entry/entry_64.S:287 -> #0 ((work_completion)(&hdev->bg_scan_update)){+.+.}-{0:0}: check_prev_add kernel/locking/lockdep.c:3053 [inline] check_prevs_add kernel/locking/lockdep.c:3172 [inline] validate_chain kernel/locking/lockdep.c:3788 [inline] __lock_acquire+0x2c33/0x7c60 kernel/locking/lockdep.c:5012 lock_acquire+0x197/0x3f0 kernel/locking/lockdep.c:5623 __flush_work+0xdd/0x1b0 kernel/workqueue.c:3090 __cancel_work_timer+0x3ac/0x520 kernel/workqueue.c:3181 hci_request_cancel_all+0xcc/0x300 net/bluetooth/hci_request.c:3522 hci_dev_do_close+0x4e/0x1030 net/bluetooth/hci_core.c:1736 hci_rfkill_set_block+0x10a/0x190 net/bluetooth/hci_core.c:2235 rfkill_set_block+0x1c6/0x420 net/rfkill/core.c:345 rfkill_fop_write+0x458/0x560 net/rfkill/core.c:1274 vfs_write+0x300/0xd00 fs/read_write.c:592 ksys_write+0x14d/0x250 fs/read_write.c:647 do_syscall_x64 arch/x86/entry/common.c:50 [inline] do_syscall_64+0x4c/0xa0 arch/x86/entry/common.c:80 entry_SYSCALL_64_after_hwframe+0x66/0xd0 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.0.16/4318: #0: ffffffff8d4b2748 (rfkill_global_mutex){+.+.}-{3:3}, at: rfkill_fop_write+0x19e/0x560 net/rfkill/core.c:1266 stack backtrace: CPU: 0 PID: 4318 Comm: syz.0.16 Not tainted 5.15.185-syzkaller #0 Hardware name: Google Google Compute Engine/Google Compute Engine, BIOS Google 05/07/2025 Call Trace: dump_stack_lvl+0x168/0x230 lib/dump_stack.c:106 check_noncircular+0x274/0x310 kernel/locking/lockdep.c:2133 check_prev_add kernel/locking/lockdep.c:3053 [inline] check_prevs_add kernel/locking/lockdep.c:3172 [inline] validate_chain kernel/locking/lockdep.c:3788 [inline] __lock_acquire+0x2c33/0x7c60 kernel/locking/lockdep.c:5012 lock_acquire+0x197/0x3f0 kernel/locking/lockdep.c:5623 __flush_work+0xdd/0x1b0 kernel/workqueue.c:3090 __cancel_work_timer+0x3ac/0x520 kernel/workqueue.c:3181 hci_request_cancel_all+0xcc/0x300 net/bluetooth/hci_request.c:3522 hci_dev_do_close+0x4e/0x1030 net/bluetooth/hci_core.c:1736 hci_rfkill_set_block+0x10a/0x190 net/bluetooth/hci_core.c:2235 rfkill_set_block+0x1c6/0x420 net/rfkill/core.c:345 rfkill_fop_write+0x458/0x560 net/rfkill/core.c:1274 vfs_write+0x300/0xd00 fs/read_write.c:592 ksys_write+0x14d/0x250 fs/read_write.c:647 do_syscall_x64 arch/x86/entry/common.c:50 [inline] do_syscall_64+0x4c/0xa0 arch/x86/entry/common.c:80 entry_SYSCALL_64_after_hwframe+0x66/0xd0 RIP: 0033:0x7f61b342c929 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 a8 ff ff ff f7 d8 64 89 01 48 RSP: 002b:00007ffece7d16a8 EFLAGS: 00000246 ORIG_RAX: 0000000000000001 RAX: ffffffffffffffda RBX: 00007f61b3653fa0 RCX: 00007f61b342c929 RDX: 0000000000000008 RSI: 0000200000000080 RDI: 0000000000000003 RBP: 00007f61b34aeb39 R08: 0000000000000000 R09: 0000000000000000 R10: 0000000000000000 R11: 0000000000000246 R12: 0000000000000000 R13: 00007f61b3653fa0 R14: 00007f61b3653fa0 R15: 0000000000000003