Extracting prog: 5m52.583788768s Minimizing prog: 36m28.847982974s Simplifying prog options: 12m11.613289368s Extracting C: 5m13.625248567s Simplifying C: 0s extracting reproducer from 1 programs testing a last program of every proc 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 CallComments:true LegacyOptions:{Collide:false Fault:false FaultCall:0 FaultNth:0}}): syz_init_net_socket$bt_sco-connect$bt_sco-syz_clone-ptrace-writev-openat-ioctl$FS_IOC_SETFLAGS detailed listing: executing program 0: r0 = syz_init_net_socket$bt_sco(0x1f, 0x5, 0x2) connect$bt_sco(r0, &(0x7f0000000000)={0x1f, @none}, 0x8) r1 = syz_clone(0x8000000, 0x0, 0x0, 0x0, 0x0, 0x0) ptrace(0x10, r1) writev(0xffffffffffffffff, 0x0, 0x0) r2 = openat(0xffffffffffffff9c, &(0x7f0000000040)='.\x00', 0x0, 0x0) ioctl$FS_IOC_SETFLAGS(r2, 0x40086602, &(0x7f0000000280)=0x20) program did not crash single: failed to extract reproducer single: executing 1 programs separately with timeout 6m0s testing program (duration=6m0s, {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 CallComments:true LegacyOptions:{Collide:false Fault:false FaultCall:0 FaultNth:0}}): syz_init_net_socket$bt_sco-connect$bt_sco-syz_clone-ptrace-writev-openat-ioctl$FS_IOC_SETFLAGS detailed listing: executing program 0: r0 = syz_init_net_socket$bt_sco(0x1f, 0x5, 0x2) connect$bt_sco(r0, &(0x7f0000000000)={0x1f, @none}, 0x8) r1 = syz_clone(0x8000000, 0x0, 0x0, 0x0, 0x0, 0x0) ptrace(0x10, r1) writev(0xffffffffffffffff, 0x0, 0x0) r2 = openat(0xffffffffffffff9c, &(0x7f0000000040)='.\x00', 0x0, 0x0) ioctl$FS_IOC_SETFLAGS(r2, 0x40086602, &(0x7f0000000280)=0x20) program crashed: possible deadlock in hci_conn_hash_flush single: successfully extracted reproducer found reproducer with 7 syscalls minimizing guilty program testing program (duration=6m0s, {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 CallComments:true LegacyOptions:{Collide:false Fault:false FaultCall:0 FaultNth:0}}): syz_init_net_socket$bt_sco-connect$bt_sco-syz_clone-ptrace-writev-openat detailed listing: executing program 0: r0 = syz_init_net_socket$bt_sco(0x1f, 0x5, 0x2) connect$bt_sco(r0, &(0x7f0000000000)={0x1f, @none}, 0x8) r1 = syz_clone(0x8000000, 0x0, 0x0, 0x0, 0x0, 0x0) ptrace(0x10, r1) writev(0xffffffffffffffff, 0x0, 0x0) openat(0xffffffffffffff9c, &(0x7f0000000040)='.\x00', 0x0, 0x0) program crashed: possible deadlock in hci_conn_hash_flush testing program (duration=6m0s, {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 CallComments:true LegacyOptions:{Collide:false Fault:false FaultCall:0 FaultNth:0}}): syz_init_net_socket$bt_sco-connect$bt_sco-syz_clone-ptrace-writev detailed listing: executing program 0: r0 = syz_init_net_socket$bt_sco(0x1f, 0x5, 0x2) connect$bt_sco(r0, &(0x7f0000000000)={0x1f, @none}, 0x8) r1 = syz_clone(0x8000000, 0x0, 0x0, 0x0, 0x0, 0x0) ptrace(0x10, r1) writev(0xffffffffffffffff, 0x0, 0x0) program crashed: possible deadlock in hci_conn_hash_flush testing program (duration=6m0s, {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 CallComments:true LegacyOptions:{Collide:false Fault:false FaultCall:0 FaultNth:0}}): syz_init_net_socket$bt_sco-connect$bt_sco-syz_clone-ptrace detailed listing: executing program 0: r0 = syz_init_net_socket$bt_sco(0x1f, 0x5, 0x2) connect$bt_sco(r0, &(0x7f0000000000)={0x1f, @none}, 0x8) r1 = syz_clone(0x8000000, 0x0, 0x0, 0x0, 0x0, 0x0) ptrace(0x10, r1) program crashed: possible deadlock in hci_conn_hash_flush testing program (duration=6m0s, {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 CallComments:true LegacyOptions:{Collide:false Fault:false FaultCall:0 FaultNth:0}}): syz_init_net_socket$bt_sco-connect$bt_sco-syz_clone detailed listing: executing program 0: r0 = syz_init_net_socket$bt_sco(0x1f, 0x5, 0x2) connect$bt_sco(r0, &(0x7f0000000000)={0x1f, @none}, 0x8) syz_clone(0x8000000, 0x0, 0x0, 0x0, 0x0, 0x0) program did not crash testing program (duration=6m0s, {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 CallComments:true LegacyOptions:{Collide:false Fault:false FaultCall:0 FaultNth:0}}): syz_init_net_socket$bt_sco-connect$bt_sco-ptrace detailed listing: executing program 0: r0 = syz_init_net_socket$bt_sco(0x1f, 0x5, 0x2) connect$bt_sco(r0, &(0x7f0000000000)={0x1f, @none}, 0x8) ptrace(0x10, 0x0) program did not crash testing program (duration=6m0s, {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 CallComments:true LegacyOptions:{Collide:false Fault:false FaultCall:0 FaultNth:0}}): syz_init_net_socket$bt_sco-syz_clone-ptrace detailed listing: executing program 0: syz_init_net_socket$bt_sco(0x1f, 0x5, 0x2) r0 = syz_clone(0x8000000, 0x0, 0x0, 0x0, 0x0, 0x0) ptrace(0x10, r0) program did not crash testing program (duration=6m0s, {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 CallComments:true LegacyOptions:{Collide:false Fault:false FaultCall:0 FaultNth:0}}): connect$bt_sco-syz_clone-ptrace detailed listing: executing program 0: connect$bt_sco(0xffffffffffffffff, &(0x7f0000000000)={0x1f, @none}, 0x8) r0 = syz_clone(0x8000000, 0x0, 0x0, 0x0, 0x0, 0x0) ptrace(0x10, r0) program did not crash testing program (duration=6m0s, {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 CallComments:true LegacyOptions:{Collide:false Fault:false FaultCall:0 FaultNth:0}}): syz_init_net_socket$bt_sco-connect$bt_sco-syz_clone-ptrace detailed listing: executing program 0: r0 = syz_init_net_socket$bt_sco(0x1f, 0x5, 0x2) connect$bt_sco(r0, 0x0, 0x0) r1 = syz_clone(0x8000000, 0x0, 0x0, 0x0, 0x0, 0x0) ptrace(0x10, r1) program did not crash extracting C reproducer testing compiled C program (duration=6m0s, {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 CallComments:true LegacyOptions:{Collide:false Fault:false FaultCall:0 FaultNth:0}}): syz_init_net_socket$bt_sco-connect$bt_sco-syz_clone-ptrace program crashed: no output from test machine a never seen crash title: no output from test machine, ignore simplifying guilty program options testing program (duration=6m0s, {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 CallComments:true LegacyOptions:{Collide:false Fault:false FaultCall:0 FaultNth:0}}): syz_init_net_socket$bt_sco-connect$bt_sco-syz_clone-ptrace detailed listing: executing program 0: r0 = syz_init_net_socket$bt_sco(0x1f, 0x5, 0x2) connect$bt_sco(r0, &(0x7f0000000000)={0x1f, @none}, 0x8) r1 = syz_clone(0x8000000, 0x0, 0x0, 0x0, 0x0, 0x0) ptrace(0x10, r1) program did not crash testing program (duration=6m0s, {Threaded:true Repeat:true RepeatTimes:0 Procs:1 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 CallComments:true LegacyOptions:{Collide:false Fault:false FaultCall:0 FaultNth:0}}): syz_init_net_socket$bt_sco-connect$bt_sco-syz_clone-ptrace detailed listing: executing program 0: r0 = syz_init_net_socket$bt_sco(0x1f, 0x5, 0x2) connect$bt_sco(r0, &(0x7f0000000000)={0x1f, @none}, 0x8) r1 = syz_clone(0x8000000, 0x0, 0x0, 0x0, 0x0, 0x0) ptrace(0x10, r1) program did not crash testing program (duration=6m0s, {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 CallComments:true LegacyOptions:{Collide:false Fault:false FaultCall:0 FaultNth:0}}): syz_init_net_socket$bt_sco-connect$bt_sco-syz_clone-ptrace detailed listing: executing program 0: r0 = syz_init_net_socket$bt_sco(0x1f, 0x5, 0x2) connect$bt_sco(r0, &(0x7f0000000000)={0x1f, @none}, 0x8) r1 = syz_clone(0x8000000, 0x0, 0x0, 0x0, 0x0, 0x0) ptrace(0x10, r1) program crashed: possible deadlock in hci_conn_hash_flush validation run: crashed=true testing program (duration=6m0s, {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 CallComments:true LegacyOptions:{Collide:false Fault:false FaultCall:0 FaultNth:0}}): syz_init_net_socket$bt_sco-connect$bt_sco-syz_clone-ptrace detailed listing: executing program 0: r0 = syz_init_net_socket$bt_sco(0x1f, 0x5, 0x2) connect$bt_sco(r0, &(0x7f0000000000)={0x1f, @none}, 0x8) r1 = syz_clone(0x8000000, 0x0, 0x0, 0x0, 0x0, 0x0) ptrace(0x10, r1) program crashed: possible deadlock in hci_conn_hash_flush validation run: crashed=true testing program (duration=6m0s, {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 CallComments:true LegacyOptions:{Collide:false Fault:false FaultCall:0 FaultNth:0}}): syz_init_net_socket$bt_sco-connect$bt_sco-syz_clone-ptrace detailed listing: executing program 0: r0 = syz_init_net_socket$bt_sco(0x1f, 0x5, 0x2) connect$bt_sco(r0, &(0x7f0000000000)={0x1f, @none}, 0x8) r1 = syz_clone(0x8000000, 0x0, 0x0, 0x0, 0x0, 0x0) ptrace(0x10, r1) program crashed: possible deadlock in hci_conn_hash_flush validation run: crashed=true reproducing took 1h5m35.423504053s repro crashed as (corrupted=false): ====================================================== WARNING: possible circular locking dependency detected syzkaller #0 Not tainted ------------------------------------------------------ syz.3.384/5699 is trying to acquire lock: ffff888077182270 ((work_completion)(&(&conn->timeout_work)->work)){+.+.}-{0:0}, at: __flush_work+0xfa/0x210 kernel/workqueue.c:3090 but task is already holding lock: ffffffff8d581ee8 (hci_cb_list_lock){+.+.}-{3:3}, at: hci_disconn_cfm include/net/bluetooth/hci_core.h:1519 [inline] ffffffff8d581ee8 (hci_cb_list_lock){+.+.}-{3:3}, at: hci_conn_hash_flush+0xa4/0x220 net/bluetooth/hci_conn.c:1622 which lock already depends on the new lock. the existing dependency chain (in reverse order) is: -> #3 (hci_cb_list_lock){+.+.}-{3:3}: __mutex_lock_common+0x1e5/0x2400 kernel/locking/mutex.c:596 __mutex_lock kernel/locking/mutex.c:729 [inline] mutex_lock_nested+0x17/0x20 kernel/locking/mutex.c:743 hci_connect_cfm include/net/bluetooth/hci_core.h:1504 [inline] hci_remote_features_evt+0x5d9/0xa10 net/bluetooth/hci_event.c:3369 hci_event_packet+0x600/0x1310 net/bluetooth/hci_event.c:6456 hci_rx_work+0x255/0xa10 net/bluetooth/hci_core.c:5190 process_one_work+0x867/0xff0 kernel/workqueue.c:2310 worker_thread+0xad7/0x12a0 kernel/workqueue.c:2457 kthread+0x42e/0x520 kernel/kthread.c:334 ret_from_fork+0x1f/0x30 arch/x86/entry/entry_64.S:287 -> #2 (&hdev->lock){+.+.}-{3:3}: __mutex_lock_common+0x1e5/0x2400 kernel/locking/mutex.c:596 __mutex_lock kernel/locking/mutex.c:729 [inline] mutex_lock_nested+0x17/0x20 kernel/locking/mutex.c:743 sco_sock_connect+0x189/0x940 net/bluetooth/sco.c:602 __sys_connect_file net/socket.c:1933 [inline] __sys_connect+0x3cb/0x450 net/socket.c:1950 __do_sys_connect net/socket.c:1960 [inline] __se_sys_connect net/socket.c:1957 [inline] __x64_sys_connect+0x76/0x80 net/socket.c:1957 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 -> #1 (sk_lock-AF_BLUETOOTH-BTPROTO_SCO){+.+.}-{0:0}: lock_sock_nested+0x44/0x100 net/core/sock.c:3259 lock_sock include/net/sock.h:1744 [inline] sco_sock_timeout+0x124/0x2d0 net/bluetooth/sco.c:108 process_one_work+0x867/0xff0 kernel/workqueue.c:2310 worker_thread+0xad7/0x12a0 kernel/workqueue.c:2457 kthread+0x42e/0x520 kernel/kthread.c:334 ret_from_fork+0x1f/0x30 arch/x86/entry/entry_64.S:287 -> #0 ((work_completion)(&(&conn->timeout_work)->work)){+.+.}-{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+0x2c66/0x7b50 kernel/locking/lockdep.c:5012 lock_acquire+0x19e/0x400 kernel/locking/lockdep.c:5623 __flush_work+0x116/0x210 kernel/workqueue.c:3090 __cancel_work_timer+0x3f4/0x560 kernel/workqueue.c:3181 sco_conn_del+0x24c/0x350 net/bluetooth/sco.c:214 hci_disconn_cfm include/net/bluetooth/hci_core.h:1522 [inline] hci_conn_hash_flush+0x107/0x220 net/bluetooth/hci_conn.c:1622 hci_dev_do_close+0x918/0x1020 net/bluetooth/hci_core.c:1813 hci_unregister_dev+0x2eb/0x590 net/bluetooth/hci_core.c:4070 vhci_release+0x73/0xc0 drivers/bluetooth/hci_vhci.c:345 __fput+0x212/0x8c0 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+0x635/0x2110 kernel/exit.c:884 do_group_exit+0x12c/0x2f0 kernel/exit.c:998 get_signal+0x7eb/0x12e0 kernel/signal.c:2901 arch_do_signal_or_restart+0xe6/0x12a0 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+0xee/0x180 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 ret_from_fork+0x15/0x30 arch/x86/entry/entry_64.S:280 other info that might help us debug this: Chain exists of: (work_completion)(&(&conn->timeout_work)->work) --> &hdev->lock --> hci_cb_list_lock Possible unsafe locking scenario: CPU0 CPU1 ---- ---- lock(hci_cb_list_lock); lock(&hdev->lock); lock(hci_cb_list_lock); lock((work_completion)(&(&conn->timeout_work)->work)); *** DEADLOCK *** 3 locks held by syz.3.384/5699: #0: ffff88802adb13f0 (&hdev->req_lock){+.+.}-{3:3}, at: hci_dev_do_close+0x5f/0x1020 net/bluetooth/hci_core.c:1755 #1: ffff88802adb0478 (&hdev->lock){+.+.}-{3:3}, at: hci_dev_do_close+0x408/0x1020 net/bluetooth/hci_core.c:1800 #2: ffffffff8d581ee8 (hci_cb_list_lock){+.+.}-{3:3}, at: hci_disconn_cfm include/net/bluetooth/hci_core.h:1519 [inline] #2: ffffffff8d581ee8 (hci_cb_list_lock){+.+.}-{3:3}, at: hci_conn_hash_flush+0xa4/0x220 net/bluetooth/hci_conn.c:1622 stack backtrace: CPU: 1 PID: 5699 Comm: syz.3.384 Not tainted syzkaller #0 Hardware name: Google Google Compute Engine/Google Compute Engine, BIOS Google 05/09/2026 Call Trace: dump_stack_lvl+0x188/0x250 lib/dump_stack.c:106 check_noncircular+0x296/0x330 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+0x2c66/0x7b50 kernel/locking/lockdep.c:5012 lock_acquire+0x19e/0x400 kernel/locking/lockdep.c:5623 __flush_work+0x116/0x210 kernel/workqueue.c:3090 __cancel_work_timer+0x3f4/0x560 kernel/workqueue.c:3181 sco_conn_del+0x24c/0x350 net/bluetooth/sco.c:214 hci_disconn_cfm include/net/bluetooth/hci_core.h:1522 [inline] hci_conn_hash_flush+0x107/0x220 net/bluetooth/hci_conn.c:1622 hci_dev_do_close+0x918/0x1020 net/bluetooth/hci_core.c:1813 hci_unregister_dev+0x2eb/0x590 net/bluetooth/hci_core.c:4070 vhci_release+0x73/0xc0 drivers/bluetooth/hci_vhci.c:345 __fput+0x212/0x8c0 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+0x635/0x2110 kernel/exit.c:884 do_group_exit+0x12c/0x2f0 kernel/exit.c:998 get_signal+0x7eb/0x12e0 kernel/signal.c:2901 arch_do_signal_or_restart+0xe6/0x12a0 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+0xee/0x180 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 ret_from_fork+0x15/0x30 arch/x86/entry/entry_64.S:280 RIP: 0033:0x7f2ecbbc7e59 Code: Unable to access opcode bytes at RIP 0x7f2ecbbc7e2f. RSP: 002b:00007f2ecb228fd8 EFLAGS: 00000206 ORIG_RAX: 0000000000000038 RAX: 0000000000000000 RBX: 00007f2ecbe40fa0 RCX: 00007f2ecbbc7e59 RDX: 0000000000000000 RSI: 0000000000000000 RDI: 0000000008000000 RBP: 00007f2ecbc5de6f R08: 0000000000000000 R09: 0000000000000000 R10: 0000000000000000 R11: 0000000000000206 R12: 0000000000000000 R13: 00007f2ecbe41038 R14: 00007f2ecbe40fa0 R15: 00007ffcc7f7ee08 final repro crashed as (corrupted=false): ====================================================== WARNING: possible circular locking dependency detected syzkaller #0 Not tainted ------------------------------------------------------ syz.3.384/5699 is trying to acquire lock: ffff888077182270 ((work_completion)(&(&conn->timeout_work)->work)){+.+.}-{0:0}, at: __flush_work+0xfa/0x210 kernel/workqueue.c:3090 but task is already holding lock: ffffffff8d581ee8 (hci_cb_list_lock){+.+.}-{3:3}, at: hci_disconn_cfm include/net/bluetooth/hci_core.h:1519 [inline] ffffffff8d581ee8 (hci_cb_list_lock){+.+.}-{3:3}, at: hci_conn_hash_flush+0xa4/0x220 net/bluetooth/hci_conn.c:1622 which lock already depends on the new lock. the existing dependency chain (in reverse order) is: -> #3 (hci_cb_list_lock){+.+.}-{3:3}: __mutex_lock_common+0x1e5/0x2400 kernel/locking/mutex.c:596 __mutex_lock kernel/locking/mutex.c:729 [inline] mutex_lock_nested+0x17/0x20 kernel/locking/mutex.c:743 hci_connect_cfm include/net/bluetooth/hci_core.h:1504 [inline] hci_remote_features_evt+0x5d9/0xa10 net/bluetooth/hci_event.c:3369 hci_event_packet+0x600/0x1310 net/bluetooth/hci_event.c:6456 hci_rx_work+0x255/0xa10 net/bluetooth/hci_core.c:5190 process_one_work+0x867/0xff0 kernel/workqueue.c:2310 worker_thread+0xad7/0x12a0 kernel/workqueue.c:2457 kthread+0x42e/0x520 kernel/kthread.c:334 ret_from_fork+0x1f/0x30 arch/x86/entry/entry_64.S:287 -> #2 (&hdev->lock){+.+.}-{3:3}: __mutex_lock_common+0x1e5/0x2400 kernel/locking/mutex.c:596 __mutex_lock kernel/locking/mutex.c:729 [inline] mutex_lock_nested+0x17/0x20 kernel/locking/mutex.c:743 sco_sock_connect+0x189/0x940 net/bluetooth/sco.c:602 __sys_connect_file net/socket.c:1933 [inline] __sys_connect+0x3cb/0x450 net/socket.c:1950 __do_sys_connect net/socket.c:1960 [inline] __se_sys_connect net/socket.c:1957 [inline] __x64_sys_connect+0x76/0x80 net/socket.c:1957 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 -> #1 (sk_lock-AF_BLUETOOTH-BTPROTO_SCO){+.+.}-{0:0}: lock_sock_nested+0x44/0x100 net/core/sock.c:3259 lock_sock include/net/sock.h:1744 [inline] sco_sock_timeout+0x124/0x2d0 net/bluetooth/sco.c:108 process_one_work+0x867/0xff0 kernel/workqueue.c:2310 worker_thread+0xad7/0x12a0 kernel/workqueue.c:2457 kthread+0x42e/0x520 kernel/kthread.c:334 ret_from_fork+0x1f/0x30 arch/x86/entry/entry_64.S:287 -> #0 ((work_completion)(&(&conn->timeout_work)->work)){+.+.}-{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+0x2c66/0x7b50 kernel/locking/lockdep.c:5012 lock_acquire+0x19e/0x400 kernel/locking/lockdep.c:5623 __flush_work+0x116/0x210 kernel/workqueue.c:3090 __cancel_work_timer+0x3f4/0x560 kernel/workqueue.c:3181 sco_conn_del+0x24c/0x350 net/bluetooth/sco.c:214 hci_disconn_cfm include/net/bluetooth/hci_core.h:1522 [inline] hci_conn_hash_flush+0x107/0x220 net/bluetooth/hci_conn.c:1622 hci_dev_do_close+0x918/0x1020 net/bluetooth/hci_core.c:1813 hci_unregister_dev+0x2eb/0x590 net/bluetooth/hci_core.c:4070 vhci_release+0x73/0xc0 drivers/bluetooth/hci_vhci.c:345 __fput+0x212/0x8c0 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+0x635/0x2110 kernel/exit.c:884 do_group_exit+0x12c/0x2f0 kernel/exit.c:998 get_signal+0x7eb/0x12e0 kernel/signal.c:2901 arch_do_signal_or_restart+0xe6/0x12a0 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+0xee/0x180 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 ret_from_fork+0x15/0x30 arch/x86/entry/entry_64.S:280 other info that might help us debug this: Chain exists of: (work_completion)(&(&conn->timeout_work)->work) --> &hdev->lock --> hci_cb_list_lock Possible unsafe locking scenario: CPU0 CPU1 ---- ---- lock(hci_cb_list_lock); lock(&hdev->lock); lock(hci_cb_list_lock); lock((work_completion)(&(&conn->timeout_work)->work)); *** DEADLOCK *** 3 locks held by syz.3.384/5699: #0: ffff88802adb13f0 (&hdev->req_lock){+.+.}-{3:3}, at: hci_dev_do_close+0x5f/0x1020 net/bluetooth/hci_core.c:1755 #1: ffff88802adb0478 (&hdev->lock){+.+.}-{3:3}, at: hci_dev_do_close+0x408/0x1020 net/bluetooth/hci_core.c:1800 #2: ffffffff8d581ee8 (hci_cb_list_lock){+.+.}-{3:3}, at: hci_disconn_cfm include/net/bluetooth/hci_core.h:1519 [inline] #2: ffffffff8d581ee8 (hci_cb_list_lock){+.+.}-{3:3}, at: hci_conn_hash_flush+0xa4/0x220 net/bluetooth/hci_conn.c:1622 stack backtrace: CPU: 1 PID: 5699 Comm: syz.3.384 Not tainted syzkaller #0 Hardware name: Google Google Compute Engine/Google Compute Engine, BIOS Google 05/09/2026 Call Trace: dump_stack_lvl+0x188/0x250 lib/dump_stack.c:106 check_noncircular+0x296/0x330 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+0x2c66/0x7b50 kernel/locking/lockdep.c:5012 lock_acquire+0x19e/0x400 kernel/locking/lockdep.c:5623 __flush_work+0x116/0x210 kernel/workqueue.c:3090 __cancel_work_timer+0x3f4/0x560 kernel/workqueue.c:3181 sco_conn_del+0x24c/0x350 net/bluetooth/sco.c:214 hci_disconn_cfm include/net/bluetooth/hci_core.h:1522 [inline] hci_conn_hash_flush+0x107/0x220 net/bluetooth/hci_conn.c:1622 hci_dev_do_close+0x918/0x1020 net/bluetooth/hci_core.c:1813 hci_unregister_dev+0x2eb/0x590 net/bluetooth/hci_core.c:4070 vhci_release+0x73/0xc0 drivers/bluetooth/hci_vhci.c:345 __fput+0x212/0x8c0 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+0x635/0x2110 kernel/exit.c:884 do_group_exit+0x12c/0x2f0 kernel/exit.c:998 get_signal+0x7eb/0x12e0 kernel/signal.c:2901 arch_do_signal_or_restart+0xe6/0x12a0 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+0xee/0x180 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 ret_from_fork+0x15/0x30 arch/x86/entry/entry_64.S:280 RIP: 0033:0x7f2ecbbc7e59 Code: Unable to access opcode bytes at RIP 0x7f2ecbbc7e2f. RSP: 002b:00007f2ecb228fd8 EFLAGS: 00000206 ORIG_RAX: 0000000000000038 RAX: 0000000000000000 RBX: 00007f2ecbe40fa0 RCX: 00007f2ecbbc7e59 RDX: 0000000000000000 RSI: 0000000000000000 RDI: 0000000008000000 RBP: 00007f2ecbc5de6f R08: 0000000000000000 R09: 0000000000000000 R10: 0000000000000000 R11: 0000000000000206 R12: 0000000000000000 R13: 00007f2ecbe41038 R14: 00007f2ecbe40fa0 R15: 00007ffcc7f7ee08