nci: __nci_request: wait_for_completion_interruptible_timeout failed -512 ====================================================== WARNING: possible circular locking dependency detected syzkaller #0 Not tainted ------------------------------------------------------ syz.1.15/4438 is trying to acquire lock: ffffffff8d41a128 (nci_mutex){+.+.}-{3:3}, at: virtual_nci_close+0x13/0x40 drivers/nfc/virtual_ncidev.c:44 but task is already holding lock: ffff88805685d350 (&ndev->req_lock){+.+.}-{3:3}, at: nci_close_device+0x102/0x600 net/nfc/nci/core.c:560 which lock already depends on the new lock. the existing dependency chain (in reverse order) is: -> #3 (&ndev->req_lock){+.+.}-{3:3}: __mutex_lock_common kernel/locking/mutex.c:603 [inline] __mutex_lock+0x12d/0xae0 kernel/locking/mutex.c:747 nci_request net/nfc/nci/core.c:148 [inline] nci_start_poll+0x8c8/0xcc0 net/nfc/nci/core.c:855 nfc_start_poll+0x141/0x2c0 net/nfc/core.c:225 nfc_genl_start_poll+0x1d7/0x340 net/nfc/netlink.c:828 genl_family_rcv_msg_doit+0x22f/0x350 net/netlink/genetlink.c:756 genl_family_rcv_msg net/netlink/genetlink.c:833 [inline] genl_rcv_msg+0x601/0x790 net/netlink/genetlink.c:850 netlink_rcv_skb+0x1ef/0x440 net/netlink/af_netlink.c:2516 genl_rcv+0x24/0x40 net/netlink/genetlink.c:861 netlink_unicast_kernel net/netlink/af_netlink.c:1318 [inline] netlink_unicast+0x7ad/0x920 net/netlink/af_netlink.c:1344 netlink_sendmsg+0x8ad/0xbd0 net/netlink/af_netlink.c:1877 sock_sendmsg_nosec net/socket.c:718 [inline] __sock_sendmsg net/socket.c:730 [inline] ____sys_sendmsg+0x5ed/0x9a0 net/socket.c:2519 ___sys_sendmsg+0x2a2/0x360 net/socket.c:2573 __sys_sendmsg net/socket.c:2602 [inline] __do_sys_sendmsg net/socket.c:2611 [inline] __se_sys_sendmsg+0x1c3/0x2b0 net/socket.c:2609 do_syscall_x64 arch/x86/entry/common.c:46 [inline] do_syscall_64+0x4c/0xa0 arch/x86/entry/common.c:76 entry_SYSCALL_64_after_hwframe+0x68/0xd2 -> #2 (&genl_data->genl_data_mutex){+.+.}-{3:3}: __mutex_lock_common kernel/locking/mutex.c:603 [inline] __mutex_lock+0x12d/0xae0 kernel/locking/mutex.c:747 nfc_urelease_event_work+0x120/0x310 net/nfc/netlink.c:1849 process_one_work+0x8ab/0x1160 kernel/workqueue.c:2292 worker_thread+0xaf5/0x12a0 kernel/workqueue.c:2439 kthread+0x29d/0x330 kernel/kthread.c:376 ret_from_fork+0x1f/0x30 arch/x86/entry/entry_64.S:295 -> #1 (nfc_devlist_mutex){+.+.}-{3:3}: __mutex_lock_common kernel/locking/mutex.c:603 [inline] __mutex_lock+0x12d/0xae0 kernel/locking/mutex.c:747 nfc_register_device+0x38/0x300 net/nfc/core.c:1116 nci_register_device+0x89f/0x9f0 net/nfc/nci/core.c:1272 virtual_ncidev_open+0x55/0xc0 drivers/nfc/virtual_ncidev.c:146 misc_open+0x31f/0x390 drivers/char/misc.c:145 chrdev_open+0x585/0x5f0 fs/char_dev.c:414 do_dentry_open+0x7dd/0x10b0 fs/open.c:882 do_open fs/namei.c:3677 [inline] path_openat+0x2674/0x2f10 fs/namei.c:3834 do_filp_open+0x1ee/0x420 fs/namei.c:3861 do_sys_openat2+0x14b/0x4f0 fs/open.c:1320 do_sys_open fs/open.c:1336 [inline] __do_sys_openat fs/open.c:1352 [inline] __se_sys_openat fs/open.c:1347 [inline] __x64_sys_openat+0x135/0x160 fs/open.c:1347 do_syscall_x64 arch/x86/entry/common.c:46 [inline] do_syscall_64+0x4c/0xa0 arch/x86/entry/common.c:76 entry_SYSCALL_64_after_hwframe+0x68/0xd2 -> #0 (nci_mutex){+.+.}-{3:3}: check_prev_add kernel/locking/lockdep.c:3095 [inline] check_prevs_add kernel/locking/lockdep.c:3214 [inline] validate_chain kernel/locking/lockdep.c:3830 [inline] __lock_acquire+0x2d18/0x7c40 kernel/locking/lockdep.c:5063 lock_acquire+0x1bb/0x4a0 kernel/locking/lockdep.c:5676 __mutex_lock_common kernel/locking/mutex.c:603 [inline] __mutex_lock+0x12d/0xae0 kernel/locking/mutex.c:747 virtual_nci_close+0x13/0x40 drivers/nfc/virtual_ncidev.c:44 nci_close_device+0x383/0x600 net/nfc/nci/core.c:591 nci_unregister_device+0x5e/0x250 net/nfc/nci/core.c:1309 virtual_ncidev_close+0x55/0x90 drivers/nfc/virtual_ncidev.c:166 __fput+0x20a/0x8b0 fs/file_table.c:320 task_work_run+0x1d0/0x260 kernel/task_work.c:203 resume_user_mode_work include/linux/resume_user_mode.h:49 [inline] exit_to_user_mode_loop+0xe6/0x110 kernel/entry/common.c:177 exit_to_user_mode_prepare+0xee/0x180 kernel/entry/common.c:210 __syscall_exit_to_user_mode_work kernel/entry/common.c:292 [inline] syscall_exit_to_user_mode+0x16/0x40 kernel/entry/common.c:303 do_syscall_64+0x58/0xa0 arch/x86/entry/common.c:82 entry_SYSCALL_64_after_hwframe+0x68/0xd2 other info that might help us debug this: Chain exists of: nci_mutex --> &genl_data->genl_data_mutex --> &ndev->req_lock Possible unsafe locking scenario: CPU0 CPU1 ---- ---- lock(&ndev->req_lock); lock(&genl_data->genl_data_mutex); lock(&ndev->req_lock); lock(nci_mutex); *** DEADLOCK *** 1 lock held by syz.1.15/4438: #0: ffff88805685d350 (&ndev->req_lock){+.+.}-{3:3}, at: nci_close_device+0x102/0x600 net/nfc/nci/core.c:560 stack backtrace: CPU: 1 PID: 4438 Comm: syz.1.15 Not tainted syzkaller #0 Hardware name: Google Google Compute Engine/Google Compute Engine, BIOS Google 07/24/2026 Call Trace: dump_stack_lvl+0x188/0x24e lib/dump_stack.c:106 check_noncircular+0x296/0x330 kernel/locking/lockdep.c:2170 check_prev_add kernel/locking/lockdep.c:3095 [inline] check_prevs_add kernel/locking/lockdep.c:3214 [inline] validate_chain kernel/locking/lockdep.c:3830 [inline] __lock_acquire+0x2d18/0x7c40 kernel/locking/lockdep.c:5063 lock_acquire+0x1bb/0x4a0 kernel/locking/lockdep.c:5676 __mutex_lock_common kernel/locking/mutex.c:603 [inline] __mutex_lock+0x12d/0xae0 kernel/locking/mutex.c:747 virtual_nci_close+0x13/0x40 drivers/nfc/virtual_ncidev.c:44 nci_close_device+0x383/0x600 net/nfc/nci/core.c:591 nci_unregister_device+0x5e/0x250 net/nfc/nci/core.c:1309 virtual_ncidev_close+0x55/0x90 drivers/nfc/virtual_ncidev.c:166 __fput+0x20a/0x8b0 fs/file_table.c:320 task_work_run+0x1d0/0x260 kernel/task_work.c:203 resume_user_mode_work include/linux/resume_user_mode.h:49 [inline] exit_to_user_mode_loop+0xe6/0x110 kernel/entry/common.c:177 exit_to_user_mode_prepare+0xee/0x180 kernel/entry/common.c:210 __syscall_exit_to_user_mode_work kernel/entry/common.c:292 [inline] syscall_exit_to_user_mode+0x16/0x40 kernel/entry/common.c:303 do_syscall_64+0x58/0xa0 arch/x86/entry/common.c:82 entry_SYSCALL_64_after_hwframe+0x68/0xd2 RIP: 0033:0x7fc54b99e0d9 Code: ff c3 66 2e 0f 1f 84 00 00 00 00 00 0f 1f 44 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 e8 ff ff ff f7 d8 64 89 01 48 RSP: 002b:00007ffea1f997f8 EFLAGS: 00000246 ORIG_RAX: 00000000000001b4 RAX: 0000000000000000 RBX: 00007fc54bc27da0 RCX: 00007fc54b99e0d9 RDX: 0000000000000000 RSI: 000000000000001e RDI: 0000000000000003 RBP: 00007fc54bc27da0 R08: 0000000000000006 R09: 0000000000000000 R10: 00007fc54bc27cb0 R11: 0000000000000246 R12: 0000000000013979 R13: 00007fc54bc2618c R14: 000000000001371a R15: 00007fc54bc26180