Hello, syzbot found the following issue on: HEAD commit: 940fcc189c51 Add linux-next specific files for 20230921 git tree: linux-next console+strace: https://syzkaller.appspot.com/x/log.txt?x=127d4f64680000 kernel config: https://syzkaller.appspot.com/x/.config?x=1f140ae6e669ac24 dashboard link: https://syzkaller.appspot.com/bug?extid=4e3a76c5c505a3f49083 compiler: gcc (Debian 12.2.0-14) 12.2.0, GNU ld (GNU Binutils for Debian) 2.40 syz repro: https://syzkaller.appspot.com/x/repro.syz?x=1081124a680000 C reproducer: https://syzkaller.appspot.com/x/repro.c?x=10cfe14a680000 Downloadable assets: disk image: https://storage.googleapis.com/syzbot-assets/b8921b235c24/disk-940fcc18.raw.xz vmlinux: https://storage.googleapis.com/syzbot-assets/c80a9f6bcdd4/vmlinux-940fcc18.xz kernel image: https://storage.googleapis.com/syzbot-assets/ed10a4df6950/bzImage-940fcc18.xz The issue was bisected to: commit 091e25d6b54992d1d702ae91cbac139d4c243251 Author: Arkadiusz Bokowy <arkadiusz.bokowy@xxxxxxxxx> Date: Wed Sep 20 15:30:07 2023 +0000 Bluetooth: vhci: Fix race when opening vhci device bisection log: https://syzkaller.appspot.com/x/bisect.txt?x=1326e53c680000 final oops: https://syzkaller.appspot.com/x/report.txt?x=10a6e53c680000 console output: https://syzkaller.appspot.com/x/log.txt?x=1726e53c680000 IMPORTANT: if you fix the issue, please add the following tag to the commit: Reported-by: syzbot+4e3a76c5c505a3f49083@xxxxxxxxxxxxxxxxxxxxxxxxx Fixes: 091e25d6b549 ("Bluetooth: vhci: Fix race when opening vhci device") ====================================================== WARNING: possible circular locking dependency detected 6.6.0-rc2-next-20230921-syzkaller #0 Not tainted ------------------------------------------------------ syz-executor126/5053 is trying to acquire lock: ffff88807df1cdc0 ((work_completion)(&hdev->tx_work)){+.+.}-{0:0}, at: __flush_work+0xfa/0xa10 kernel/workqueue.c:3403 but task is already holding lock: ffff88807df1d0b8 (&hdev->req_lock){+.+.}-{3:3}, at: hci_dev_do_close+0x26/0x90 net/bluetooth/hci_core.c:552 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:603 [inline] __mutex_lock+0x181/0x1340 kernel/locking/mutex.c:747 hci_dev_do_close+0x26/0x90 net/bluetooth/hci_core.c:552 hci_rfkill_set_block+0x1b9/0x200 net/bluetooth/hci_core.c:956 rfkill_set_block+0x200/0x550 net/rfkill/core.c:346 rfkill_fop_write+0x2d4/0x570 net/rfkill/core.c:1306 vfs_write+0x2a4/0xe40 fs/read_write.c:582 ksys_write+0x1f0/0x250 fs/read_write.c:637 do_syscall_x64 arch/x86/entry/common.c:51 [inline] do_syscall_64+0x38/0xb0 arch/x86/entry/common.c:81 entry_SYSCALL_64_after_hwframe+0x63/0xcd -> #2 (rfkill_global_mutex){+.+.}-{3:3}: __mutex_lock_common kernel/locking/mutex.c:603 [inline] __mutex_lock+0x181/0x1340 kernel/locking/mutex.c:747 rfkill_register+0x3a/0xb30 net/rfkill/core.c:1075 hci_register_dev+0x43a/0xd40 net/bluetooth/hci_core.c:2656 __vhci_create_device+0x393/0x800 drivers/bluetooth/hci_vhci.c:437 vhci_create_device drivers/bluetooth/hci_vhci.c:478 [inline] vhci_get_user drivers/bluetooth/hci_vhci.c:535 [inline] vhci_write+0x2c7/0x470 drivers/bluetooth/hci_vhci.c:615 call_write_iter include/linux/fs.h:1957 [inline] new_sync_write fs/read_write.c:491 [inline] vfs_write+0x650/0xe40 fs/read_write.c:584 ksys_write+0x12f/0x250 fs/read_write.c:637 do_syscall_x64 arch/x86/entry/common.c:51 [inline] do_syscall_64+0x38/0xb0 arch/x86/entry/common.c:81 entry_SYSCALL_64_after_hwframe+0x63/0xcd -> #1 (&data->open_mutex){+.+.}-{3:3}: __mutex_lock_common kernel/locking/mutex.c:603 [inline] __mutex_lock+0x181/0x1340 kernel/locking/mutex.c:747 vhci_send_frame+0x67/0xa0 drivers/bluetooth/hci_vhci.c:78 hci_send_frame+0x220/0x470 net/bluetooth/hci_core.c:3039 hci_sched_acl_pkt net/bluetooth/hci_core.c:3651 [inline] hci_sched_acl net/bluetooth/hci_core.c:3736 [inline] hci_tx_work+0x1456/0x1e40 net/bluetooth/hci_core.c:3835 process_one_work+0x884/0x15c0 kernel/workqueue.c:2630 process_scheduled_works kernel/workqueue.c:2703 [inline] worker_thread+0x8b9/0x1290 kernel/workqueue.c:2784 kthread+0x33c/0x440 kernel/kthread.c:388 ret_from_fork+0x45/0x80 arch/x86/kernel/process.c:147 ret_from_fork_asm+0x11/0x20 arch/x86/entry/entry_64.S:304 -> #0 ((work_completion)(&hdev->tx_work)){+.+.}-{0:0}: check_prev_add kernel/locking/lockdep.c:3134 [inline] check_prevs_add kernel/locking/lockdep.c:3253 [inline] validate_chain kernel/locking/lockdep.c:3868 [inline] __lock_acquire+0x2e3d/0x5de0 kernel/locking/lockdep.c:5136 lock_acquire kernel/locking/lockdep.c:5753 [inline] lock_acquire+0x1ae/0x510 kernel/locking/lockdep.c:5718 __flush_work+0x103/0xa10 kernel/workqueue.c:3403 hci_dev_close_sync+0x22d/0x1160 net/bluetooth/hci_sync.c:4982 hci_dev_do_close+0x2e/0x90 net/bluetooth/hci_core.c:554 hci_rfkill_set_block+0x1b9/0x200 net/bluetooth/hci_core.c:956 rfkill_set_block+0x200/0x550 net/rfkill/core.c:346 rfkill_fop_write+0x2d4/0x570 net/rfkill/core.c:1306 vfs_write+0x2a4/0xe40 fs/read_write.c:582 ksys_write+0x1f0/0x250 fs/read_write.c:637 do_syscall_x64 arch/x86/entry/common.c:51 [inline] do_syscall_64+0x38/0xb0 arch/x86/entry/common.c:81 entry_SYSCALL_64_after_hwframe+0x63/0xcd 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-executor126/5053: #0: ffffffff8ea842a8 (rfkill_global_mutex){+.+.}-{3:3}, at: rfkill_fop_write+0x16e/0x570 net/rfkill/core.c:1298 #1: ffff88807df1d0b8 (&hdev->req_lock){+.+.}-{3:3}, at: hci_dev_do_close+0x26/0x90 net/bluetooth/hci_core.c:552 stack backtrace: CPU: 1 PID: 5053 Comm: syz-executor126 Not tainted 6.6.0-rc2-next-20230921-syzkaller #0 Hardware name: Google Google Compute Engine/Google Compute Engine, BIOS Google 08/04/2023 Call Trace: <TASK> __dump_stack lib/dump_stack.c:88 [inline] dump_stack_lvl+0xd9/0x1b0 lib/dump_stack.c:106 check_noncircular+0x311/0x3f0 kernel/locking/lockdep.c:2187 check_prev_add kernel/locking/lockdep.c:3134 [inline] check_prevs_add kernel/locking/lockdep.c:3253 [inline] validate_chain kernel/locking/lockdep.c:3868 [inline] __lock_acquire+0x2e3d/0x5de0 kernel/locking/lockdep.c:5136 lock_acquire kernel/locking/lockdep.c:5753 [inline] lock_acquire+0x1ae/0x510 kernel/locking/lockdep.c:5718 __flush_work+0x103/0xa10 kernel/workqueue.c:3403 hci_dev_close_sync+0x22d/0x1160 net/bluetooth/hci_sync.c:4982 hci_dev_do_close+0x2e/0x90 net/bluetooth/hci_core.c:554 hci_rfkill_set_block+0x1b9/0x200 net/bluetooth/hci_core.c:956 rfkill_set_block+0x200/0x550 net/rfkill/core.c:346 rfkill_fop_write+0x2d4/0x570 net/rfkill/core.c:1306 vfs_write+0x2a4/0xe40 fs/read_write.c:582 ksys_write+0x1f0/0x250 fs/read_write.c:637 do_syscall_x64 arch/x86/entry/common.c:51 [inline] do_syscall_64+0x38/0xb0 arch/x86/entry/common.c:81 entry_SYSCALL_64_after_hwframe+0x63/0xcd RIP: 0033:0x7f8297388479 Code: 48 83 c4 28 c3 e8 e7 18 00 00 0f 1f 80 00 00 00 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 b0 ff ff ff f7 d8 64 89 01 48 RSP: 002b:00007ffc9ef0d068 EFLAGS: 00000246 ORIG_RAX: 0000000000000001 RAX: ffffffffffffffda RBX: 00007f82973df043 RCX: 00007f8297388479 RDX: 0000000000000008 RSI: 0000000020000080 RDI: 0000000000000003 RBP: 00007ffc9ef0d0b0 R08: 000000ff00ffa650 R09: 000000ff00ffa650 R10: 0000000000000000 R11: 0000000000000246 R12: 00007ffc9ef0d098 R13: 00007f829740c5b0 R14: 0000000000000000 R15: 0000000000000001 </TASK> --- This report is generated by a bot. It may contain errors. See https://goo.gl/tpsmEJ for more information about syzbot. syzbot engineers can be reached at syzkaller@xxxxxxxxxxxxxxxx. syzbot will keep track of this issue. See: https://goo.gl/tpsmEJ#status for how to communicate with syzbot. For information about bisection process see: https://goo.gl/tpsmEJ#bisection If the bug is already fixed, let syzbot know by replying with: #syz fix: exact-commit-title If you want syzbot to run the reproducer, reply with: #syz test: git://repo/address.git branch-or-commit-hash If you attach or paste a git patch, syzbot will apply it before testing. If you want to overwrite bug's subsystems, reply with: #syz set subsystems: new-subsystem (See the list of subsystem names on the web dashboard) If the bug is a duplicate of another bug, reply with: #syz dup: exact-subject-of-another-report If you want to undo deduplication, reply with: #syz undup
