====================================================== WARNING: possible circular locking dependency detected 6.1.0-syzkaller #0 Not tainted ------------------------------------------------------ syz-executor.4/25791 is trying to acquire lock: ffff88803b3c6350 (&ndev->req_lock){+.+.}-{3:3}, at: nci_request net/nfc/nci/core.c:148 [inline] ffff88803b3c6350 (&ndev->req_lock){+.+.}-{3:3}, at: nci_set_local_general_bytes net/nfc/nci/core.c:774 [inline] ffff88803b3c6350 (&ndev->req_lock){+.+.}-{3:3}, at: nci_start_poll+0x688/0x900 net/nfc/nci/core.c:838 but task is already holding lock: ffff88803b3c5508 (&genl_data->genl_data_mutex){+.+.}-{3:3}, at: nfc_genl_start_poll+0x19e/0x490 net/nfc/netlink.c:826 which lock already depends on the new lock. the existing dependency chain (in reverse order) is: -> #3 (&genl_data->genl_data_mutex){+.+.}-{3:3}: __mutex_lock_common kernel/locking/mutex.c:603 [inline] __mutex_lock+0x12f/0x1360 kernel/locking/mutex.c:747 nfc_urelease_event_work+0x143/0x2d0 net/nfc/netlink.c:1811 process_one_work+0x9bf/0x1710 kernel/workqueue.c:2289 worker_thread+0x669/0x1090 kernel/workqueue.c:2436 kthread+0x2e8/0x3a0 kernel/kthread.c:376 ret_from_fork+0x1f/0x30 arch/x86/entry/entry_64.S:306 -> #2 (nfc_devlist_mutex){+.+.}-{3:3}: __mutex_lock_common kernel/locking/mutex.c:603 [inline] __mutex_lock+0x12f/0x1360 kernel/locking/mutex.c:747 nfc_register_device+0x32/0x3b0 net/nfc/core.c:1116 nci_register_device+0x7cb/0xb50 net/nfc/nci/core.c:1256 virtual_ncidev_open+0x71/0x110 drivers/nfc/virtual_ncidev.c:146 misc_open+0x37a/0x4a0 drivers/char/misc.c:143 chrdev_open+0x26a/0x770 fs/char_dev.c:414 do_dentry_open+0x6cc/0x13f0 fs/open.c:882 do_open fs/namei.c:3557 [inline] path_openat+0x1bf6/0x2860 fs/namei.c:3714 do_filp_open+0x1ba/0x410 fs/namei.c:3741 do_sys_openat2+0x16d/0x4c0 fs/open.c:1310 do_sys_open fs/open.c:1326 [inline] __do_sys_openat fs/open.c:1342 [inline] __se_sys_openat fs/open.c:1337 [inline] __x64_sys_openat+0x143/0x1f0 fs/open.c:1337 do_syscall_x64 arch/x86/entry/common.c:50 [inline] do_syscall_64+0x39/0xb0 arch/x86/entry/common.c:80 entry_SYSCALL_64_after_hwframe+0x63/0xcd -> #1 (nci_mutex){+.+.}-{3:3}: __mutex_lock_common kernel/locking/mutex.c:603 [inline] __mutex_lock+0x12f/0x1360 kernel/locking/mutex.c:747 virtual_nci_close+0x17/0x50 drivers/nfc/virtual_ncidev.c:44 nci_open_device net/nfc/nci/core.c:544 [inline] nci_dev_up+0x4cb/0x660 net/nfc/nci/core.c:631 nfc_dev_up+0x1aa/0x3b0 net/nfc/core.c:118 nfc_genl_dev_up+0xa6/0xf0 net/nfc/netlink.c:770 genl_family_rcv_msg_doit+0x228/0x320 net/netlink/genetlink.c:756 genl_family_rcv_msg net/netlink/genetlink.c:833 [inline] genl_rcv_msg+0x445/0x780 net/netlink/genetlink.c:850 netlink_rcv_skb+0x157/0x430 net/netlink/af_netlink.c:2540 genl_rcv+0x28/0x40 net/netlink/genetlink.c:861 netlink_unicast_kernel net/netlink/af_netlink.c:1319 [inline] netlink_unicast+0x547/0x7f0 net/netlink/af_netlink.c:1345 netlink_sendmsg+0x91b/0xe10 net/netlink/af_netlink.c:1921 sock_sendmsg_nosec net/socket.c:714 [inline] sock_sendmsg+0xd3/0x120 net/socket.c:734 ____sys_sendmsg+0x712/0x8c0 net/socket.c:2482 ___sys_sendmsg+0x110/0x1b0 net/socket.c:2536 __sys_sendmsg+0xf7/0x1c0 net/socket.c:2565 do_syscall_x64 arch/x86/entry/common.c:50 [inline] do_syscall_64+0x39/0xb0 arch/x86/entry/common.c:80 entry_SYSCALL_64_after_hwframe+0x63/0xcd -> #0 (&ndev->req_lock){+.+.}-{3:3}: check_prev_add kernel/locking/lockdep.c:3097 [inline] check_prevs_add kernel/locking/lockdep.c:3216 [inline] validate_chain kernel/locking/lockdep.c:3831 [inline] __lock_acquire+0x2a43/0x56d0 kernel/locking/lockdep.c:5055 lock_acquire kernel/locking/lockdep.c:5668 [inline] lock_acquire+0x1e3/0x630 kernel/locking/lockdep.c:5633 __mutex_lock_common kernel/locking/mutex.c:603 [inline] __mutex_lock+0x12f/0x1360 kernel/locking/mutex.c:747 nci_request net/nfc/nci/core.c:148 [inline] nci_set_local_general_bytes net/nfc/nci/core.c:774 [inline] nci_start_poll+0x688/0x900 net/nfc/nci/core.c:838 nfc_start_poll+0x192/0x320 net/nfc/core.c:225 nfc_genl_start_poll+0x1ac/0x490 net/nfc/netlink.c:828 genl_family_rcv_msg_doit+0x228/0x320 net/netlink/genetlink.c:756 genl_family_rcv_msg net/netlink/genetlink.c:833 [inline] genl_rcv_msg+0x445/0x780 net/netlink/genetlink.c:850 netlink_rcv_skb+0x157/0x430 net/netlink/af_netlink.c:2540 genl_rcv+0x28/0x40 net/netlink/genetlink.c:861 netlink_unicast_kernel net/netlink/af_netlink.c:1319 [inline] netlink_unicast+0x547/0x7f0 net/netlink/af_netlink.c:1345 netlink_sendmsg+0x91b/0xe10 net/netlink/af_netlink.c:1921 sock_sendmsg_nosec net/socket.c:714 [inline] sock_sendmsg+0xd3/0x120 net/socket.c:734 ____sys_sendmsg+0x712/0x8c0 net/socket.c:2482 ___sys_sendmsg+0x110/0x1b0 net/socket.c:2536 __sys_sendmsg+0xf7/0x1c0 net/socket.c:2565 do_syscall_x64 arch/x86/entry/common.c:50 [inline] do_syscall_64+0x39/0xb0 arch/x86/entry/common.c:80 entry_SYSCALL_64_after_hwframe+0x63/0xcd other info that might help us debug this: Chain exists of: &ndev->req_lock --> nfc_devlist_mutex --> &genl_data->genl_data_mutex Possible unsafe locking scenario: CPU0 CPU1 ---- ---- lock(&genl_data->genl_data_mutex); lock(nfc_devlist_mutex); lock(&genl_data->genl_data_mutex); lock(&ndev->req_lock); *** DEADLOCK *** 4 locks held by syz-executor.4/25791: #0: ffffffff8df508f0 (cb_lock){++++}-{3:3}, at: genl_rcv+0x19/0x40 net/netlink/genetlink.c:860 #1: ffffffff8df509a8 (genl_mutex){+.+.}-{3:3}, at: genl_lock net/netlink/genetlink.c:33 [inline] #1: ffffffff8df509a8 (genl_mutex){+.+.}-{3:3}, at: genl_rcv_msg+0x50d/0x780 net/netlink/genetlink.c:848 #2: ffff88803b3c5508 (&genl_data->genl_data_mutex){+.+.}-{3:3}, at: nfc_genl_start_poll+0x19e/0x490 net/nfc/netlink.c:826 #3: ffff88803b3c5100 (&dev->mutex){....}-{3:3}, at: device_lock include/linux/device.h:835 [inline] #3: ffff88803b3c5100 (&dev->mutex){....}-{3:3}, at: nfc_start_poll+0x58/0x320 net/nfc/core.c:208 stack backtrace: CPU: 0 PID: 25791 Comm: syz-executor.4 Not tainted 6.1.0-syzkaller #0 Hardware name: Google Google Compute Engine/Google Compute Engine, BIOS Google 10/26/2022 Call Trace: __dump_stack lib/dump_stack.c:88 [inline] dump_stack_lvl+0xd1/0x138 lib/dump_stack.c:106 check_noncircular+0x25f/0x2e0 kernel/locking/lockdep.c:2177 check_prev_add kernel/locking/lockdep.c:3097 [inline] check_prevs_add kernel/locking/lockdep.c:3216 [inline] validate_chain kernel/locking/lockdep.c:3831 [inline] __lock_acquire+0x2a43/0x56d0 kernel/locking/lockdep.c:5055 lock_acquire kernel/locking/lockdep.c:5668 [inline] lock_acquire+0x1e3/0x630 kernel/locking/lockdep.c:5633 __mutex_lock_common kernel/locking/mutex.c:603 [inline] __mutex_lock+0x12f/0x1360 kernel/locking/mutex.c:747 nci_request net/nfc/nci/core.c:148 [inline] nci_set_local_general_bytes net/nfc/nci/core.c:774 [inline] nci_start_poll+0x688/0x900 net/nfc/nci/core.c:838 nfc_start_poll+0x192/0x320 net/nfc/core.c:225 nfc_genl_start_poll+0x1ac/0x490 net/nfc/netlink.c:828 genl_family_rcv_msg_doit+0x228/0x320 net/netlink/genetlink.c:756 genl_family_rcv_msg net/netlink/genetlink.c:833 [inline] genl_rcv_msg+0x445/0x780 net/netlink/genetlink.c:850 netlink_rcv_skb+0x157/0x430 net/netlink/af_netlink.c:2540 genl_rcv+0x28/0x40 net/netlink/genetlink.c:861 netlink_unicast_kernel net/netlink/af_netlink.c:1319 [inline] netlink_unicast+0x547/0x7f0 net/netlink/af_netlink.c:1345 netlink_sendmsg+0x91b/0xe10 net/netlink/af_netlink.c:1921 sock_sendmsg_nosec net/socket.c:714 [inline] sock_sendmsg+0xd3/0x120 net/socket.c:734 ____sys_sendmsg+0x712/0x8c0 net/socket.c:2482 ___sys_sendmsg+0x110/0x1b0 net/socket.c:2536 __sys_sendmsg+0xf7/0x1c0 net/socket.c:2565 do_syscall_x64 arch/x86/entry/common.c:50 [inline] do_syscall_64+0x39/0xb0 arch/x86/entry/common.c:80 entry_SYSCALL_64_after_hwframe+0x63/0xcd RIP: 0033:0x7facd248c0d9 Code: 28 00 00 00 75 05 48 83 c4 28 c3 e8 f1 19 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 b8 ff ff ff f7 d8 64 89 01 48 RSP: 002b:00007facd3219168 EFLAGS: 00000246 ORIG_RAX: 000000000000002e RAX: ffffffffffffffda RBX: 00007facd25ac050 RCX: 00007facd248c0d9 RDX: 0000000000000000 RSI: 0000000020000440 RDI: 0000000000000006 RBP: 00007facd24e7ae9 R08: 0000000000000000 R09: 0000000000000000 R10: 0000000000000000 R11: 0000000000000246 R12: 0000000000000000 R13: 00007ffeb048cf9f R14: 00007facd3219300 R15: 0000000000022000