====================================================== WARNING: possible circular locking dependency detected 4.14.169-syzkaller #0 Not tainted ------------------------------------------------------ syz-executor.0/13804 is trying to acquire lock: ((&strp->work)){+.+.}, at: [] flush_work+0x84/0x730 kernel/workqueue.c:2884 but task is already holding lock: (sk_lock-AF_INET){+.+.}, at: [] lock_sock include/net/sock.h:1467 [inline] (sk_lock-AF_INET){+.+.}, at: [] kcm_attach net/kcm/kcmsock.c:1390 [inline] (sk_lock-AF_INET){+.+.}, at: [] kcm_attach_ioctl net/kcm/kcmsock.c:1490 [inline] (sk_lock-AF_INET){+.+.}, at: [] kcm_ioctl+0x35d/0x1120 net/kcm/kcmsock.c:1701 which lock already depends on the new lock. the existing dependency chain (in reverse order) is: -> #1 (sk_lock-AF_INET){+.+.}: lock_acquire+0x16f/0x430 kernel/locking/lockdep.c:3994 lock_sock_nested+0xbd/0x110 net/core/sock.c:2770 lock_sock include/net/sock.h:1467 [inline] strp_sock_lock+0x2e/0x40 net/strparser/strparser.c:451 do_strp_work net/strparser/strparser.c:415 [inline] strp_work+0x43/0x100 net/strparser/strparser.c:434 process_one_work+0x863/0x1600 kernel/workqueue.c:2114 worker_thread+0x5d9/0x1050 kernel/workqueue.c:2248 kthread+0x319/0x430 kernel/kthread.c:232 ret_from_fork+0x24/0x30 arch/x86/entry/entry_64.S:404 -> #0 ((&strp->work)){+.+.}: check_prev_add kernel/locking/lockdep.c:1901 [inline] check_prevs_add kernel/locking/lockdep.c:2018 [inline] validate_chain kernel/locking/lockdep.c:2460 [inline] __lock_acquire+0x2cb3/0x4620 kernel/locking/lockdep.c:3487 lock_acquire+0x16f/0x430 kernel/locking/lockdep.c:3994 flush_work+0xae/0x730 kernel/workqueue.c:2887 __cancel_work_timer+0x2f0/0x480 kernel/workqueue.c:2962 cancel_work_sync+0x18/0x20 kernel/workqueue.c:2998 strp_done+0x58/0xe0 net/strparser/strparser.c:519 kcm_attach net/kcm/kcmsock.c:1429 [inline] kcm_attach_ioctl net/kcm/kcmsock.c:1490 [inline] kcm_ioctl+0x8d9/0x1120 net/kcm/kcmsock.c:1701 sock_do_ioctl+0x64/0xb0 net/socket.c:974 sock_ioctl+0x2a6/0x470 net/socket.c:1071 vfs_ioctl fs/ioctl.c:46 [inline] file_ioctl fs/ioctl.c:500 [inline] do_vfs_ioctl+0x7ae/0x1060 fs/ioctl.c:684 SYSC_ioctl fs/ioctl.c:701 [inline] SyS_ioctl+0x8f/0xc0 fs/ioctl.c:692 do_syscall_64+0x1e8/0x640 arch/x86/entry/common.c:292 entry_SYSCALL_64_after_hwframe+0x42/0xb7 other info that might help us debug this: Possible unsafe locking scenario: CPU0 CPU1 ---- ---- lock(sk_lock-AF_INET); lock((&strp->work)); lock(sk_lock-AF_INET); lock((&strp->work)); *** DEADLOCK *** 1 lock held by syz-executor.0/13804: #0: (sk_lock-AF_INET){+.+.}, at: [] lock_sock include/net/sock.h:1467 [inline] #0: (sk_lock-AF_INET){+.+.}, at: [] kcm_attach net/kcm/kcmsock.c:1390 [inline] #0: (sk_lock-AF_INET){+.+.}, at: [] kcm_attach_ioctl net/kcm/kcmsock.c:1490 [inline] #0: (sk_lock-AF_INET){+.+.}, at: [] kcm_ioctl+0x35d/0x1120 net/kcm/kcmsock.c:1701 stack backtrace: CPU: 1 PID: 13804 Comm: syz-executor.0 Not tainted 4.14.169-syzkaller #0 Hardware name: Google Google Compute Engine/Google Compute Engine, BIOS Google 01/01/2011 Call Trace: __dump_stack lib/dump_stack.c:17 [inline] dump_stack+0x142/0x197 lib/dump_stack.c:58 print_circular_bug.isra.0.cold+0x1cc/0x28f kernel/locking/lockdep.c:1258 check_prev_add kernel/locking/lockdep.c:1901 [inline] check_prevs_add kernel/locking/lockdep.c:2018 [inline] validate_chain kernel/locking/lockdep.c:2460 [inline] __lock_acquire+0x2cb3/0x4620 kernel/locking/lockdep.c:3487 lock_acquire+0x16f/0x430 kernel/locking/lockdep.c:3994 flush_work+0xae/0x730 kernel/workqueue.c:2887 __cancel_work_timer+0x2f0/0x480 kernel/workqueue.c:2962 cancel_work_sync+0x18/0x20 kernel/workqueue.c:2998 strp_done+0x58/0xe0 net/strparser/strparser.c:519 kcm_attach net/kcm/kcmsock.c:1429 [inline] kcm_attach_ioctl net/kcm/kcmsock.c:1490 [inline] kcm_ioctl+0x8d9/0x1120 net/kcm/kcmsock.c:1701 sock_do_ioctl+0x64/0xb0 net/socket.c:974 sock_ioctl+0x2a6/0x470 net/socket.c:1071 vfs_ioctl fs/ioctl.c:46 [inline] file_ioctl fs/ioctl.c:500 [inline] do_vfs_ioctl+0x7ae/0x1060 fs/ioctl.c:684 SYSC_ioctl fs/ioctl.c:701 [inline] SyS_ioctl+0x8f/0xc0 fs/ioctl.c:692 do_syscall_64+0x1e8/0x640 arch/x86/entry/common.c:292 entry_SYSCALL_64_after_hwframe+0x42/0xb7 RIP: 0033:0x45b349 RSP: 002b:00007f14ac963c78 EFLAGS: 00000246 ORIG_RAX: 0000000000000010 RAX: ffffffffffffffda RBX: 00007f14ac9646d4 RCX: 000000000045b349 RDX: 0000000020000380 RSI: 00000000000089e0 RDI: 0000000000000009 RBP: 000000000075c070 R08: 0000000000000000 R09: 0000000000000000 R10: 0000000000000000 R11: 0000000000000246 R12: 00000000ffffffff R13: 00000000000006d2 R14: 00000000004c8499 R15: 000000000075c07c Bluetooth: hci0 command 0x1003 tx timeout Bluetooth: hci0 sending frame failed (-49) Bluetooth: hci1 command 0x1003 tx timeout Bluetooth: hci1 sending frame failed (-49) NOHZ: local_softirq_pending 08 Bluetooth: hci0 command 0x1001 tx timeout Bluetooth: hci0 sending frame failed (-49) Bluetooth: hci1 command 0x1001 tx timeout Bluetooth: hci1 sending frame failed (-49) Bluetooth: hci0 command 0x1009 tx timeout Bluetooth: hci1 command 0x1009 tx timeout