syzbot

======================================================
WARNING: possible circular locking dependency detected
5.15.153-syzkaller #0 Not tainted
------------------------------------------------------
syz-executor.3/9815 is trying to acquire lock:
ffff8880767df350 (&ndev->req_lock){+.+.}-{3:3}, at: nci_request net/nfc/nci/core.c:148 [inline]
ffff8880767df350 (&ndev->req_lock){+.+.}-{3:3}, at: nci_set_local_general_bytes net/nfc/nci/core.c:774 [inline]
ffff8880767df350 (&ndev->req_lock){+.+.}-{3:3}, at: nci_start_poll+0x59f/0xf20 net/nfc/nci/core.c:838

but task is already holding lock:
ffff8880767de5d0 (&genl_data->genl_data_mutex){+.+.}-{3:3}, at: nfc_genl_start_poll+0x1da/0x350 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}:
       lock_acquire+0x1db/0x4f0 kernel/locking/lockdep.c:5623
       __mutex_lock_common+0x1da/0x25a0 kernel/locking/mutex.c:596
       __mutex_lock kernel/locking/mutex.c:729 [inline]
       mutex_lock_nested+0x17/0x20 kernel/locking/mutex.c:743
       nfc_urelease_event_work+0x113/0x2f0 net/nfc/netlink.c:1833
       process_one_work+0x8a1/0x10c0 kernel/workqueue.c:2310
       worker_thread+0xaca/0x1280 kernel/workqueue.c:2457
       kthread+0x3f6/0x4f0 kernel/kthread.c:319
       ret_from_fork+0x1f/0x30 arch/x86/entry/entry_64.S:298

-> #2 (nfc_devlist_mutex){+.+.}-{3:3}:
       lock_acquire+0x1db/0x4f0 kernel/locking/lockdep.c:5623
       __mutex_lock_common+0x1da/0x25a0 kernel/locking/mutex.c:596
       __mutex_lock kernel/locking/mutex.c:729 [inline]
       mutex_lock_nested+0x17/0x20 kernel/locking/mutex.c:743
       nfc_register_device+0x38/0x310 net/nfc/core.c:1116
       nci_register_device+0x7be/0x900 net/nfc/nci/core.c:1269
       virtual_ncidev_open+0x55/0xc0 drivers/nfc/virtual_ncidev.c:146
       misc_open+0x304/0x380 drivers/char/misc.c:141
       chrdev_open+0x54a/0x630 fs/char_dev.c:414
       do_dentry_open+0x807/0xfb0 fs/open.c:826
       do_open fs/namei.c:3608 [inline]
       path_openat+0x2702/0x2f20 fs/namei.c:3742
       do_filp_open+0x21c/0x460 fs/namei.c:3769
       do_sys_openat2+0x13b/0x500 fs/open.c:1211
       do_sys_open fs/open.c:1227 [inline]
       __do_sys_openat fs/open.c:1243 [inline]
       __se_sys_openat fs/open.c:1238 [inline]
       __x64_sys_openat+0x243/0x290 fs/open.c:1238
       do_syscall_x64 arch/x86/entry/common.c:50 [inline]
       do_syscall_64+0x3d/0xb0 arch/x86/entry/common.c:80
       entry_SYSCALL_64_after_hwframe+0x61/0xcb

-> #1 (nci_mutex){+.+.}-{3:3}:
       lock_acquire+0x1db/0x4f0 kernel/locking/lockdep.c:5623
       __mutex_lock_common+0x1da/0x25a0 kernel/locking/mutex.c:596
       __mutex_lock kernel/locking/mutex.c:729 [inline]
       mutex_lock_nested+0x17/0x20 kernel/locking/mutex.c:743
       virtual_nci_close+0x13/0x40 drivers/nfc/virtual_ncidev.c:44
       nci_close_device+0x3a8/0x5f0 net/nfc/nci/core.c:592
       nci_unregister_device+0x3c/0x230 net/nfc/nci/core.c:1304
       virtual_ncidev_close+0x55/0x90 drivers/nfc/virtual_ncidev.c:166
       __fput+0x3bf/0x890 fs/file_table.c:280
       task_work_run+0x129/0x1a0 kernel/task_work.c:164
       get_signal+0x143a/0x14e0 kernel/signal.c:2661
       arch_do_signal_or_restart+0xc3/0x1890 arch/x86/kernel/signal.c:867
       handle_signal_work kernel/entry/common.c:148 [inline]
       exit_to_user_mode_loop+0x97/0x130 kernel/entry/common.c:172
       exit_to_user_mode_prepare+0xb1/0x140 kernel/entry/common.c:208
       __syscall_exit_to_user_mode_work kernel/entry/common.c:290 [inline]
       syscall_exit_to_user_mode+0x5d/0x250 kernel/entry/common.c:301
       do_syscall_64+0x49/0xb0 arch/x86/entry/common.c:86
       entry_SYSCALL_64_after_hwframe+0x61/0xcb

-> #0 (&ndev->req_lock){+.+.}-{3:3}:
       check_prev_add kernel/locking/lockdep.c:3053 [inline]
       check_prevs_add kernel/locking/lockdep.c:3172 [inline]
       validate_chain+0x1649/0x5930 kernel/locking/lockdep.c:3788
       __lock_acquire+0x1295/0x1ff0 kernel/locking/lockdep.c:5012
       lock_acquire+0x1db/0x4f0 kernel/locking/lockdep.c:5623
       __mutex_lock_common+0x1da/0x25a0 kernel/locking/mutex.c:596
       __mutex_lock kernel/locking/mutex.c:729 [inline]
       mutex_lock_nested+0x17/0x20 kernel/locking/mutex.c:743
       nci_request net/nfc/nci/core.c:148 [inline]
       nci_set_local_general_bytes net/nfc/nci/core.c:774 [inline]
       nci_start_poll+0x59f/0xf20 net/nfc/nci/core.c:838
       nfc_start_poll+0x184/0x2f0 net/nfc/core.c:225
       nfc_genl_start_poll+0x1e7/0x350 net/nfc/netlink.c:828
       genl_family_rcv_msg_doit net/netlink/genetlink.c:731 [inline]
       genl_family_rcv_msg net/netlink/genetlink.c:775 [inline]
       genl_rcv_msg+0xfbd/0x14a0 net/netlink/genetlink.c:792
       netlink_rcv_skb+0x1cf/0x410 net/netlink/af_netlink.c:2505
       genl_rcv+0x24/0x40 net/netlink/genetlink.c:803
       netlink_unicast_kernel net/netlink/af_netlink.c:1330 [inline]
       netlink_unicast+0x7b6/0x980 net/netlink/af_netlink.c:1356
       netlink_sendmsg+0xa30/0xd60 net/netlink/af_netlink.c:1924
       sock_sendmsg_nosec net/socket.c:704 [inline]
       __sock_sendmsg net/socket.c:716 [inline]
       ____sys_sendmsg+0x59e/0x8f0 net/socket.c:2431
       ___sys_sendmsg+0x252/0x2e0 net/socket.c:2485
       __sys_sendmsg net/socket.c:2514 [inline]
       __do_sys_sendmsg net/socket.c:2523 [inline]
       __se_sys_sendmsg+0x19a/0x260 net/socket.c:2521
       do_syscall_x64 arch/x86/entry/common.c:50 [inline]
       do_syscall_64+0x3d/0xb0 arch/x86/entry/common.c:80
       entry_SYSCALL_64_after_hwframe+0x61/0xcb

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.3/9815:
 #0: ffffffff8da39830 (cb_lock){++++}-{3:3}, at: genl_rcv+0x15/0x40 net/netlink/genetlink.c:802
 #1: ffffffff8da396e8 (genl_mutex){+.+.}-{3:3}, at: genl_lock net/netlink/genetlink.c:33 [inline]
 #1: ffffffff8da396e8 (genl_mutex){+.+.}-{3:3}, at: genl_rcv_msg+0x124/0x14a0 net/netlink/genetlink.c:790
 #2: ffff8880767de5d0 (&genl_data->genl_data_mutex){+.+.}-{3:3}, at: nfc_genl_start_poll+0x1da/0x350 net/nfc/netlink.c:826
 #3: ffff8880767de190 (&dev->mutex){....}-{3:3}, at: device_lock include/linux/device.h:760 [inline]
 #3: ffff8880767de190 (&dev->mutex){....}-{3:3}, at: nfc_start_poll+0x56/0x2f0 net/nfc/core.c:208

stack backtrace:
CPU: 1 PID: 9815 Comm: syz-executor.3 Not tainted 5.15.153-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+0x1e3/0x2cb lib/dump_stack.c:106
 check_noncircular+0x2f8/0x3b0 kernel/locking/lockdep.c:2133
 check_prev_add kernel/locking/lockdep.c:3053 [inline]
 check_prevs_add kernel/locking/lockdep.c:3172 [inline]
 validate_chain+0x1649/0x5930 kernel/locking/lockdep.c:3788
 __lock_acquire+0x1295/0x1ff0 kernel/locking/lockdep.c:5012
 lock_acquire+0x1db/0x4f0 kernel/locking/lockdep.c:5623
 __mutex_lock_common+0x1da/0x25a0 kernel/locking/mutex.c:596
 __mutex_lock kernel/locking/mutex.c:729 [inline]
 mutex_lock_nested+0x17/0x20 kernel/locking/mutex.c:743
 nci_request net/nfc/nci/core.c:148 [inline]
 nci_set_local_general_bytes net/nfc/nci/core.c:774 [inline]
 nci_start_poll+0x59f/0xf20 net/nfc/nci/core.c:838
 nfc_start_poll+0x184/0x2f0 net/nfc/core.c:225
 nfc_genl_start_poll+0x1e7/0x350 net/nfc/netlink.c:828
 genl_family_rcv_msg_doit net/netlink/genetlink.c:731 [inline]
 genl_family_rcv_msg net/netlink/genetlink.c:775 [inline]
 genl_rcv_msg+0xfbd/0x14a0 net/netlink/genetlink.c:792
 netlink_rcv_skb+0x1cf/0x410 net/netlink/af_netlink.c:2505
 genl_rcv+0x24/0x40 net/netlink/genetlink.c:803
 netlink_unicast_kernel net/netlink/af_netlink.c:1330 [inline]
 netlink_unicast+0x7b6/0x980 net/netlink/af_netlink.c:1356
 netlink_sendmsg+0xa30/0xd60 net/netlink/af_netlink.c:1924
 sock_sendmsg_nosec net/socket.c:704 [inline]
 __sock_sendmsg net/socket.c:716 [inline]
 ____sys_sendmsg+0x59e/0x8f0 net/socket.c:2431
 ___sys_sendmsg+0x252/0x2e0 net/socket.c:2485
 __sys_sendmsg net/socket.c:2514 [inline]
 __do_sys_sendmsg net/socket.c:2523 [inline]
 __se_sys_sendmsg+0x19a/0x260 net/socket.c:2521
 do_syscall_x64 arch/x86/entry/common.c:50 [inline]
 do_syscall_64+0x3d/0xb0 arch/x86/entry/common.c:80
 entry_SYSCALL_64_after_hwframe+0x61/0xcb
RIP: 0033:0x7fc052194e69
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:00007fc0506e60c8 EFLAGS: 00000246 ORIG_RAX: 000000000000002e
RAX: ffffffffffffffda RBX: 00007fc0522c3050 RCX: 00007fc052194e69
RDX: 0003000000000000 RSI: 0000000020000440 RDI: 0000000000000005
RBP: 00007fc0521e147a R08: 0000000000000000 R09: 0000000000000000
R10: 0000000000000000 R11: 0000000000000246 R12: 0000000000000000
R13: 000000000000006e R14: 00007fc0522c3050 R15: 00007fff5668a4d8
 </TASK>