Hello, syzbot found the following issue on: HEAD commit: bbed346d5a96 Merge branch 'for-next/core' into for-kernelci git tree: git://git.kernel.org/pub/scm/linux/kernel/git/arm64/linux.git for-kernelci console output: https://syzkaller.appspot.com/x/log.txt?x=1188403a880000 kernel config: https://syzkaller.appspot.com/x/.config?x=3a4a45d2d827c1e dashboard link: https://syzkaller.appspot.com/bug?extid=10c46e34f156f51a28ad compiler: Debian clang version 13.0.1-++20220126092033+75e33f71c2da-1~exp1~20220126212112.63, GNU ld (GNU Binutils for Debian) 2.35.2 userspace arch: arm64 Unfortunately, I don't have any reproducer for this issue yet. Downloadable assets: disk image: https://storage.googleapis.com/syzbot-assets/e8e91bc79312/disk-bbed346d.raw.xz vmlinux: https://storage.googleapis.com/syzbot-assets/c1cb3fb3b77e/vmlinux-bbed346d.xz IMPORTANT: if you fix the issue, please add the following tag to the commit: Reported-by: syzbot+10c46e34f156f51a28ad@xxxxxxxxxxxxxxxxxxxxxxxxx ====================================================== WARNING: possible circular locking dependency detected 6.0.0-rc7-syzkaller-18095-gbbed346d5a96 #0 Not tainted ------------------------------------------------------ kworker/1:2/31873 is trying to acquire lock: ffff000115941130 (sk_lock-AF_BLUETOOTH-BTPROTO_SCO){+.+.}-{0:0}, at: lock_sock include/net/sock.h:1712 [inline] ffff000115941130 (sk_lock-AF_BLUETOOTH-BTPROTO_SCO){+.+.}-{0:0}, at: sco_sock_timeout+0x88/0x1b8 net/bluetooth/sco.c:97 but task is already holding lock: ffff8000149abd80 ((work_completion)(&(&conn->timeout_work)->work)){+.+.}-{0:0}, at: process_one_work+0x29c/0x504 kernel/workqueue.c:2264 which lock already depends on the new lock. the existing dependency chain (in reverse order) is: -> #3 ((work_completion)(&(&conn->timeout_work)->work)){+.+.}-{0:0}: __flush_work+0x9c/0x144 kernel/workqueue.c:3069 __cancel_work_timer+0x1c4/0x2ac kernel/workqueue.c:3160 cancel_delayed_work_sync+0x24/0x38 kernel/workqueue.c:3301 sco_conn_del+0x140/0x234 net/bluetooth/sco.c:205 sco_disconn_cfm+0x64/0xa8 net/bluetooth/sco.c:1379 hci_disconn_cfm include/net/bluetooth/hci_core.h:1779 [inline] hci_conn_hash_flush+0x88/0x148 net/bluetooth/hci_conn.c:2366 hci_dev_close_sync+0x48c/0x9e0 net/bluetooth/hci_sync.c:4476 hci_dev_do_close net/bluetooth/hci_core.c:554 [inline] hci_error_reset+0xac/0x154 net/bluetooth/hci_core.c:1050 process_one_work+0x2d8/0x504 kernel/workqueue.c:2289 worker_thread+0x340/0x610 kernel/workqueue.c:2436 kthread+0x12c/0x158 kernel/kthread.c:376 ret_from_fork+0x10/0x20 arch/arm64/kernel/entry.S:860 -> #2 (hci_cb_list_lock){+.+.}-{3:3}: __mutex_lock_common+0xd4/0xca8 kernel/locking/mutex.c:603 __mutex_lock kernel/locking/mutex.c:747 [inline] mutex_lock_nested+0x38/0x44 kernel/locking/mutex.c:799 hci_connect_cfm include/net/bluetooth/hci_core.h:1761 [inline] hci_remote_features_evt+0x274/0x50c net/bluetooth/hci_event.c:3757 hci_event_func net/bluetooth/hci_event.c:7443 [inline] hci_event_packet+0x5c4/0x60c net/bluetooth/hci_event.c:7495 hci_rx_work+0x1a4/0x2f4 net/bluetooth/hci_core.c:4007 process_one_work+0x2d8/0x504 kernel/workqueue.c:2289 worker_thread+0x340/0x610 kernel/workqueue.c:2436 kthread+0x12c/0x158 kernel/kthread.c:376 ret_from_fork+0x10/0x20 arch/arm64/kernel/entry.S:860 -> #1 (&hdev->lock){+.+.}-{3:3}: __mutex_lock_common+0xd4/0xca8 kernel/locking/mutex.c:603 __mutex_lock kernel/locking/mutex.c:747 [inline] mutex_lock_nested+0x38/0x44 kernel/locking/mutex.c:799 sco_sock_connect+0x104/0x220 net/bluetooth/sco.c:593 __sys_connect_file net/socket.c:1976 [inline] __sys_connect+0x184/0x190 net/socket.c:1993 __do_sys_connect net/socket.c:2003 [inline] __se_sys_connect net/socket.c:2000 [inline] __arm64_sys_connect+0x28/0x3c net/socket.c:2000 __invoke_syscall arch/arm64/kernel/syscall.c:38 [inline] invoke_syscall arch/arm64/kernel/syscall.c:52 [inline] el0_svc_common+0x138/0x220 arch/arm64/kernel/syscall.c:142 do_el0_svc+0x48/0x164 arch/arm64/kernel/syscall.c:206 el0_svc+0x58/0x150 arch/arm64/kernel/entry-common.c:636 el0t_64_sync_handler+0x84/0xf0 arch/arm64/kernel/entry-common.c:654 el0t_64_sync+0x18c/0x190 arch/arm64/kernel/entry.S:581 -> #0 (sk_lock-AF_BLUETOOTH-BTPROTO_SCO){+.+.}-{0:0}: check_prev_add kernel/locking/lockdep.c:3095 [inline] check_prevs_add kernel/locking/lockdep.c:3214 [inline] validate_chain kernel/locking/lockdep.c:3829 [inline] __lock_acquire+0x1530/0x30a4 kernel/locking/lockdep.c:5053 lock_acquire+0x100/0x1f8 kernel/locking/lockdep.c:5666 lock_sock_nested+0x70/0xd8 net/core/sock.c:3393 lock_sock include/net/sock.h:1712 [inline] sco_sock_timeout+0x88/0x1b8 net/bluetooth/sco.c:97 process_one_work+0x2d8/0x504 kernel/workqueue.c:2289 worker_thread+0x340/0x610 kernel/workqueue.c:2436 kthread+0x12c/0x158 kernel/kthread.c:376 ret_from_fork+0x10/0x20 arch/arm64/kernel/entry.S:860 other info that might help us debug this: Chain exists of: sk_lock-AF_BLUETOOTH-BTPROTO_SCO --> hci_cb_list_lock --> (work_completion)(&(&conn->timeout_work)->work) Possible unsafe locking scenario: CPU0 CPU1 ---- ---- lock((work_completion)(&(&conn->timeout_work)->work)); lock(hci_cb_list_lock); lock((work_completion)(&(&conn->timeout_work)->work)); lock(sk_lock-AF_BLUETOOTH-BTPROTO_SCO); *** DEADLOCK *** 2 locks held by kworker/1:2/31873: #0: ffff0000c0010738 ((wq_completion)events){+.+.}-{0:0}, at: process_one_work+0x270/0x504 kernel/workqueue.c:2262 #1: ffff8000149abd80 ((work_completion)(&(&conn->timeout_work)->work)){+.+.}-{0:0}, at: process_one_work+0x29c/0x504 kernel/workqueue.c:2264 stack backtrace: CPU: 1 PID: 31873 Comm: kworker/1:2 Not tainted 6.0.0-rc7-syzkaller-18095-gbbed346d5a96 #0 Hardware name: Google Google Compute Engine/Google Compute Engine, BIOS Google 09/30/2022 Workqueue: events sco_sock_timeout Call trace: dump_backtrace+0x1c4/0x1f0 arch/arm64/kernel/stacktrace.c:156 show_stack+0x2c/0x54 arch/arm64/kernel/stacktrace.c:163 __dump_stack lib/dump_stack.c:88 [inline] dump_stack_lvl+0x104/0x16c lib/dump_stack.c:106 dump_stack+0x1c/0x58 lib/dump_stack.c:113 print_circular_bug+0x2c4/0x2c8 kernel/locking/lockdep.c:2053 check_noncircular+0x14c/0x154 kernel/locking/lockdep.c:2175 check_prev_add kernel/locking/lockdep.c:3095 [inline] check_prevs_add kernel/locking/lockdep.c:3214 [inline] validate_chain kernel/locking/lockdep.c:3829 [inline] __lock_acquire+0x1530/0x30a4 kernel/locking/lockdep.c:5053 lock_acquire+0x100/0x1f8 kernel/locking/lockdep.c:5666 lock_sock_nested+0x70/0xd8 net/core/sock.c:3393 lock_sock include/net/sock.h:1712 [inline] sco_sock_timeout+0x88/0x1b8 net/bluetooth/sco.c:97 process_one_work+0x2d8/0x504 kernel/workqueue.c:2289 worker_thread+0x340/0x610 kernel/workqueue.c:2436 kthread+0x12c/0x158 kernel/kthread.c:376 ret_from_fork+0x10/0x20 arch/arm64/kernel/entry.S:860 --- This report is generated by a bot. 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