Hello, syzbot found the following issue on: HEAD commit: bb7a2467e6be Add linux-next specific files for 20240426 git tree: linux-next console output: https://syzkaller.appspot.com/x/log.txt?x=17d7d27f180000 kernel config: https://syzkaller.appspot.com/x/.config?x=5c6a0288262dd108 dashboard link: https://syzkaller.appspot.com/bug?extid=27678574afc8747c97f3 compiler: Debian clang version 15.0.6, GNU ld (GNU Binutils for Debian) 2.40 Unfortunately, I don't have any reproducer for this issue yet. Downloadable assets: disk image: https://storage.googleapis.com/syzbot-assets/5175af7dda64/disk-bb7a2467.raw.xz vmlinux: https://storage.googleapis.com/syzbot-assets/70db0462e868/vmlinux-bb7a2467.xz kernel image: https://storage.googleapis.com/syzbot-assets/3217fb825698/bzImage-bb7a2467.xz IMPORTANT: if you fix the issue, please add the following tag to the commit: Reported-by: syzbot+27678574afc8747c97f3@xxxxxxxxxxxxxxxxxxxxxxxxx ====================================================== WARNING: possible circular locking dependency detected 6.9.0-rc5-next-20240426-syzkaller #0 Not tainted ------------------------------------------------------ syz-executor.4/20238 is trying to acquire lock: ffff888068f348d0 ((work_completion)(&hdev->cmd_sync_work)){+.+.}-{0:0}, at: rcu_lock_acquire include/linux/rcupdate.h:329 [inline] ffff888068f348d0 ((work_completion)(&hdev->cmd_sync_work)){+.+.}-{0:0}, at: rcu_read_lock include/linux/rcupdate.h:841 [inline] ffff888068f348d0 ((work_completion)(&hdev->cmd_sync_work)){+.+.}-{0:0}, at: start_flush_work kernel/workqueue.c:4113 [inline] ffff888068f348d0 ((work_completion)(&hdev->cmd_sync_work)){+.+.}-{0:0}, at: __flush_work+0xe6/0xd00 kernel/workqueue.c:4172 but task is already holding lock: ffff888068f35060 (&hdev->req_lock){+.+.}-{3:3}, at: hci_dev_do_close net/bluetooth/hci_core.c:559 [inline] ffff888068f35060 (&hdev->req_lock){+.+.}-{3:3}, at: hci_dev_close+0x10a/0x210 net/bluetooth/hci_core.c:586 which lock already depends on the new lock. the existing dependency chain (in reverse order) is: -> #1 (&hdev->req_lock){+.+.}-{3:3}: lock_acquire+0x1ed/0x550 kernel/locking/lockdep.c:5754 __mutex_lock_common kernel/locking/mutex.c:608 [inline] __mutex_lock+0x136/0xd70 kernel/locking/mutex.c:752 hci_cmd_sync_work+0x1ec/0x400 net/bluetooth/hci_sync.c:309 process_one_work kernel/workqueue.c:3222 [inline] process_scheduled_works+0xa2c/0x1830 kernel/workqueue.c:3303 worker_thread+0x86d/0xd70 kernel/workqueue.c:3384 kthread+0x2f0/0x390 kernel/kthread.c:389 ret_from_fork+0x4b/0x80 arch/x86/kernel/process.c:147 ret_from_fork_asm+0x1a/0x30 arch/x86/entry/entry_64.S:244 -> #0 ((work_completion)(&hdev->cmd_sync_work)){+.+.}-{0:0}: check_prev_add kernel/locking/lockdep.c:3134 [inline] check_prevs_add kernel/locking/lockdep.c:3253 [inline] validate_chain+0x18cb/0x58e0 kernel/locking/lockdep.c:3869 __lock_acquire+0x1346/0x1fd0 kernel/locking/lockdep.c:5137 lock_acquire+0x1ed/0x550 kernel/locking/lockdep.c:5754 touch_work_lockdep_map kernel/workqueue.c:3885 [inline] start_flush_work kernel/workqueue.c:4139 [inline] __flush_work+0x73c/0xd00 kernel/workqueue.c:4172 __cancel_work_sync+0xbc/0x110 kernel/workqueue.c:4322 hci_cmd_sync_clear+0x30/0x220 net/bluetooth/hci_sync.c:588 hci_dev_close_sync+0xbae/0x1060 net/bluetooth/hci_sync.c:5188 hci_dev_do_close net/bluetooth/hci_core.c:561 [inline] hci_dev_close+0x112/0x210 net/bluetooth/hci_core.c:586 sock_do_ioctl+0x158/0x460 net/socket.c:1222 sock_ioctl+0x629/0x8e0 net/socket.c:1341 vfs_ioctl fs/ioctl.c:51 [inline] __do_sys_ioctl fs/ioctl.c:907 [inline] __se_sys_ioctl+0xfc/0x170 fs/ioctl.c:893 do_syscall_x64 arch/x86/entry/common.c:52 [inline] do_syscall_64+0xf5/0x240 arch/x86/entry/common.c:83 entry_SYSCALL_64_after_hwframe+0x77/0x7f other info that might help us debug this: Possible unsafe locking scenario: CPU0 CPU1 ---- ---- lock(&hdev->req_lock); lock((work_completion)(&hdev->cmd_sync_work)); lock(&hdev->req_lock); lock((work_completion)(&hdev->cmd_sync_work)); *** DEADLOCK *** 2 locks held by syz-executor.4/20238: #0: ffff888068f35060 (&hdev->req_lock){+.+.}-{3:3}, at: hci_dev_do_close net/bluetooth/hci_core.c:559 [inline] #0: ffff888068f35060 (&hdev->req_lock){+.+.}-{3:3}, at: hci_dev_close+0x10a/0x210 net/bluetooth/hci_core.c:586 #1: ffffffff8e333ba0 (rcu_read_lock){....}-{1:2}, at: rcu_lock_acquire include/linux/rcupdate.h:329 [inline] #1: ffffffff8e333ba0 (rcu_read_lock){....}-{1:2}, at: rcu_read_lock include/linux/rcupdate.h:841 [inline] #1: ffffffff8e333ba0 (rcu_read_lock){....}-{1:2}, at: start_flush_work kernel/workqueue.c:4113 [inline] #1: ffffffff8e333ba0 (rcu_read_lock){....}-{1:2}, at: __flush_work+0xe6/0xd00 kernel/workqueue.c:4172 stack backtrace: CPU: 0 PID: 20238 Comm: syz-executor.4 Not tainted 6.9.0-rc5-next-20240426-syzkaller #0 Hardware name: Google Google Compute Engine/Google Compute Engine, BIOS Google 03/27/2024 Call Trace: <TASK> __dump_stack lib/dump_stack.c:88 [inline] dump_stack_lvl+0x241/0x360 lib/dump_stack.c:114 check_noncircular+0x36a/0x4a0 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+0x18cb/0x58e0 kernel/locking/lockdep.c:3869 __lock_acquire+0x1346/0x1fd0 kernel/locking/lockdep.c:5137 lock_acquire+0x1ed/0x550 kernel/locking/lockdep.c:5754 touch_work_lockdep_map kernel/workqueue.c:3885 [inline] start_flush_work kernel/workqueue.c:4139 [inline] __flush_work+0x73c/0xd00 kernel/workqueue.c:4172 __cancel_work_sync+0xbc/0x110 kernel/workqueue.c:4322 hci_cmd_sync_clear+0x30/0x220 net/bluetooth/hci_sync.c:588 hci_dev_close_sync+0xbae/0x1060 net/bluetooth/hci_sync.c:5188 hci_dev_do_close net/bluetooth/hci_core.c:561 [inline] hci_dev_close+0x112/0x210 net/bluetooth/hci_core.c:586 sock_do_ioctl+0x158/0x460 net/socket.c:1222 sock_ioctl+0x629/0x8e0 net/socket.c:1341 vfs_ioctl fs/ioctl.c:51 [inline] __do_sys_ioctl fs/ioctl.c:907 [inline] __se_sys_ioctl+0xfc/0x170 fs/ioctl.c:893 do_syscall_x64 arch/x86/entry/common.c:52 [inline] do_syscall_64+0xf5/0x240 arch/x86/entry/common.c:83 entry_SYSCALL_64_after_hwframe+0x77/0x7f RIP: 0033:0x7f978a87dea9 Code: 28 00 00 00 75 05 48 83 c4 28 c3 e8 e1 20 00 00 90 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:00007f978b6ad0c8 EFLAGS: 00000246 ORIG_RAX: 0000000000000010 RAX: ffffffffffffffda RBX: 00007f978a9abf80 RCX: 00007f978a87dea9 RDX: 0000000000000000 RSI: 00000000400448ca RDI: 000000000000000a RBP: 00007f978a8ca4a4 R08: 0000000000000000 R09: 0000000000000000 R10: 0000000000000000 R11: 0000000000000246 R12: 0000000000000000 R13: 000000000000000b R14: 00007f978a9abf80 R15: 00007fff06c0ef28 </TASK> --- This report is generated by a bot. 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