====================================================== WARNING: possible circular locking dependency detected 6.1.0-rc8-syzkaller-00018-g479174d402bc #0 Not tainted ------------------------------------------------------ syz-executor.1/27966 is trying to acquire lock: ffff00001b2f0350 (&ndev->req_lock){+.+.}-{3:3}, at: nci_request net/nfc/nci/core.c:148 [inline] ffff00001b2f0350 (&ndev->req_lock){+.+.}-{3:3}, at: nci_set_local_general_bytes net/nfc/nci/core.c:774 [inline] ffff00001b2f0350 (&ndev->req_lock){+.+.}-{3:3}, at: nci_start_poll+0x36c/0x624 net/nfc/nci/core.c:838 but task is already holding lock: ffff000014649518 (&genl_data->genl_data_mutex){+.+.}-{3:3}, at: nfc_genl_start_poll+0x144/0x3b0 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+0x124/0x83c kernel/locking/mutex.c:747 mutex_lock_nested+0x2c/0x40 kernel/locking/mutex.c:799 nfc_urelease_event_work+0x118/0x270 net/nfc/netlink.c:1811 process_one_work+0x780/0x184c kernel/workqueue.c:2289 worker_thread+0x3cc/0xc40 kernel/workqueue.c:2436 kthread+0x23c/0x2a0 kernel/kthread.c:376 ret_from_fork+0x10/0x20 arch/arm64/kernel/entry.S:860 -> #2 (nfc_devlist_mutex){+.+.}-{3:3}: __mutex_lock_common kernel/locking/mutex.c:603 [inline] __mutex_lock+0x124/0x83c kernel/locking/mutex.c:747 mutex_lock_nested+0x2c/0x40 kernel/locking/mutex.c:799 nfc_register_device+0x34/0x320 net/nfc/core.c:1116 nci_register_device+0x604/0x8c0 net/nfc/nci/core.c:1256 virtual_ncidev_open+0x64/0xe0 drivers/nfc/virtual_ncidev.c:146 misc_open+0x294/0x394 drivers/char/misc.c:143 chrdev_open+0x1c0/0x54c fs/char_dev.c:414 do_dentry_open+0x3c4/0xf40 fs/open.c:882 vfs_open+0x90/0xd0 fs/open.c:1013 do_open fs/namei.c:3557 [inline] path_openat+0x1030/0x1fe0 fs/namei.c:3714 do_filp_open+0x154/0x330 fs/namei.c:3741 do_sys_openat2+0x124/0x390 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] __arm64_sys_openat+0x130/0x1c0 fs/open.c:1337 __invoke_syscall arch/arm64/kernel/syscall.c:38 [inline] invoke_syscall+0x6c/0x260 arch/arm64/kernel/syscall.c:52 el0_svc_common.constprop.0+0xc4/0x254 arch/arm64/kernel/syscall.c:142 do_el0_svc+0x50/0x14c arch/arm64/kernel/syscall.c:206 el0_svc+0x54/0x140 arch/arm64/kernel/entry-common.c:637 el0t_64_sync_handler+0xb8/0xc0 arch/arm64/kernel/entry-common.c:655 el0t_64_sync+0x18c/0x190 arch/arm64/kernel/entry.S:581 -> #1 (nci_mutex){+.+.}-{3:3}: __mutex_lock_common kernel/locking/mutex.c:603 [inline] __mutex_lock+0x124/0x83c kernel/locking/mutex.c:747 mutex_lock_nested+0x2c/0x40 kernel/locking/mutex.c:799 virtual_nci_close+0x2c/0x60 drivers/nfc/virtual_ncidev.c:44 nci_open_device net/nfc/nci/core.c:544 [inline] nci_dev_up+0x41c/0x520 net/nfc/nci/core.c:631 nfc_dev_up+0x11c/0x2b4 net/nfc/core.c:118 nfc_genl_dev_up+0x88/0xe0 net/nfc/netlink.c:770 genl_family_rcv_msg_doit+0x1b8/0x2a0 net/netlink/genetlink.c:756 genl_family_rcv_msg net/netlink/genetlink.c:833 [inline] genl_rcv_msg+0x2f8/0x594 net/netlink/genetlink.c:850 netlink_rcv_skb+0x180/0x330 net/netlink/af_netlink.c:2540 genl_rcv+0x38/0x50 net/netlink/genetlink.c:861 netlink_unicast_kernel net/netlink/af_netlink.c:1319 [inline] netlink_unicast+0x3ec/0x684 net/netlink/af_netlink.c:1345 netlink_sendmsg+0x690/0xb1c net/netlink/af_netlink.c:1921 sock_sendmsg_nosec net/socket.c:714 [inline] sock_sendmsg+0xc0/0xf4 net/socket.c:734 ____sys_sendmsg+0x534/0x6b0 net/socket.c:2482 ___sys_sendmsg+0xf0/0x174 net/socket.c:2536 __sys_sendmsg+0xc4/0x154 net/socket.c:2565 __do_sys_sendmsg net/socket.c:2574 [inline] __se_sys_sendmsg net/socket.c:2572 [inline] __arm64_sys_sendmsg+0x70/0xa0 net/socket.c:2572 __invoke_syscall arch/arm64/kernel/syscall.c:38 [inline] invoke_syscall+0x6c/0x260 arch/arm64/kernel/syscall.c:52 el0_svc_common.constprop.0+0xc4/0x254 arch/arm64/kernel/syscall.c:142 do_el0_svc+0x50/0x14c arch/arm64/kernel/syscall.c:206 el0_svc+0x54/0x140 arch/arm64/kernel/entry-common.c:637 el0t_64_sync_handler+0xb8/0xc0 arch/arm64/kernel/entry-common.c:655 el0t_64_sync+0x18c/0x190 arch/arm64/kernel/entry.S:581 -> #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+0x2788/0x56d0 kernel/locking/lockdep.c:5055 lock_acquire kernel/locking/lockdep.c:5668 [inline] lock_acquire+0x58c/0x9a0 kernel/locking/lockdep.c:5633 __mutex_lock_common kernel/locking/mutex.c:603 [inline] __mutex_lock+0x124/0x83c kernel/locking/mutex.c:747 mutex_lock_nested+0x2c/0x40 kernel/locking/mutex.c:799 nci_request net/nfc/nci/core.c:148 [inline] nci_set_local_general_bytes net/nfc/nci/core.c:774 [inline] nci_start_poll+0x36c/0x624 net/nfc/nci/core.c:838 nfc_start_poll+0x114/0x270 net/nfc/core.c:225 nfc_genl_start_poll+0x154/0x3b0 net/nfc/netlink.c:828 genl_family_rcv_msg_doit+0x1b8/0x2a0 net/netlink/genetlink.c:756 genl_family_rcv_msg net/netlink/genetlink.c:833 [inline] genl_rcv_msg+0x2f8/0x594 net/netlink/genetlink.c:850 netlink_rcv_skb+0x180/0x330 net/netlink/af_netlink.c:2540 genl_rcv+0x38/0x50 net/netlink/genetlink.c:861 netlink_unicast_kernel net/netlink/af_netlink.c:1319 [inline] netlink_unicast+0x3ec/0x684 net/netlink/af_netlink.c:1345 netlink_sendmsg+0x690/0xb1c net/netlink/af_netlink.c:1921 sock_sendmsg_nosec net/socket.c:714 [inline] sock_sendmsg+0xc0/0xf4 net/socket.c:734 ____sys_sendmsg+0x534/0x6b0 net/socket.c:2482 ___sys_sendmsg+0xf0/0x174 net/socket.c:2536 __sys_sendmsg+0xc4/0x154 net/socket.c:2565 __do_sys_sendmsg net/socket.c:2574 [inline] __se_sys_sendmsg net/socket.c:2572 [inline] __arm64_sys_sendmsg+0x70/0xa0 net/socket.c:2572 __invoke_syscall arch/arm64/kernel/syscall.c:38 [inline] invoke_syscall+0x6c/0x260 arch/arm64/kernel/syscall.c:52 el0_svc_common.constprop.0+0xc4/0x254 arch/arm64/kernel/syscall.c:142 do_el0_svc+0x50/0x14c arch/arm64/kernel/syscall.c:206 el0_svc+0x54/0x140 arch/arm64/kernel/entry-common.c:637 el0t_64_sync_handler+0xb8/0xc0 arch/arm64/kernel/entry-common.c:655 el0t_64_sync+0x18c/0x190 arch/arm64/kernel/entry.S:581 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.1/27966: #0: ffff80000f328b70 (cb_lock){++++}-{3:3}, at: genl_rcv+0x28/0x50 net/netlink/genetlink.c:860 #1: ffff80000f328aa8 (genl_mutex){+.+.}-{3:3}, at: genl_lock net/netlink/genetlink.c:33 [inline] #1: ffff80000f328aa8 (genl_mutex){+.+.}-{3:3}, at: genl_rcv_msg+0x3d0/0x594 net/netlink/genetlink.c:848 #2: ffff000014649518 (&genl_data->genl_data_mutex){+.+.}-{3:3}, at: nfc_genl_start_poll+0x144/0x3b0 net/nfc/netlink.c:826 #3: ffff000014649100 (&dev->mutex){....}-{3:3}, at: device_lock include/linux/device.h:835 [inline] #3: ffff000014649100 (&dev->mutex){....}-{3:3}, at: nfc_start_poll+0x40/0x270 net/nfc/core.c:208 stack backtrace: CPU: 1 PID: 27966 Comm: syz-executor.1 Not tainted 6.1.0-rc8-syzkaller-00018-g479174d402bc #0 Hardware name: linux,dummy-virt (DT) Call trace: dump_backtrace+0xe0/0x140 arch/arm64/kernel/stacktrace.c:156 show_stack+0x18/0x40 arch/arm64/kernel/stacktrace.c:163 __dump_stack lib/dump_stack.c:88 [inline] dump_stack_lvl+0x9c/0xd8 lib/dump_stack.c:106 dump_stack+0x1c/0x38 lib/dump_stack.c:113 print_circular_bug+0x2d4/0x2ec kernel/locking/lockdep.c:2055 check_noncircular+0x26c/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+0x2788/0x56d0 kernel/locking/lockdep.c:5055 lock_acquire kernel/locking/lockdep.c:5668 [inline] lock_acquire+0x58c/0x9a0 kernel/locking/lockdep.c:5633 __mutex_lock_common kernel/locking/mutex.c:603 [inline] __mutex_lock+0x124/0x83c kernel/locking/mutex.c:747 mutex_lock_nested+0x2c/0x40 kernel/locking/mutex.c:799 nci_request net/nfc/nci/core.c:148 [inline] nci_set_local_general_bytes net/nfc/nci/core.c:774 [inline] nci_start_poll+0x36c/0x624 net/nfc/nci/core.c:838 nfc_start_poll+0x114/0x270 net/nfc/core.c:225 nfc_genl_start_poll+0x154/0x3b0 net/nfc/netlink.c:828 genl_family_rcv_msg_doit+0x1b8/0x2a0 net/netlink/genetlink.c:756 genl_family_rcv_msg net/netlink/genetlink.c:833 [inline] genl_rcv_msg+0x2f8/0x594 net/netlink/genetlink.c:850 netlink_rcv_skb+0x180/0x330 net/netlink/af_netlink.c:2540 genl_rcv+0x38/0x50 net/netlink/genetlink.c:861 netlink_unicast_kernel net/netlink/af_netlink.c:1319 [inline] netlink_unicast+0x3ec/0x684 net/netlink/af_netlink.c:1345 netlink_sendmsg+0x690/0xb1c net/netlink/af_netlink.c:1921 sock_sendmsg_nosec net/socket.c:714 [inline] sock_sendmsg+0xc0/0xf4 net/socket.c:734 ____sys_sendmsg+0x534/0x6b0 net/socket.c:2482 ___sys_sendmsg+0xf0/0x174 net/socket.c:2536 __sys_sendmsg+0xc4/0x154 net/socket.c:2565 __do_sys_sendmsg net/socket.c:2574 [inline] __se_sys_sendmsg net/socket.c:2572 [inline] __arm64_sys_sendmsg+0x70/0xa0 net/socket.c:2572 __invoke_syscall arch/arm64/kernel/syscall.c:38 [inline] invoke_syscall+0x6c/0x260 arch/arm64/kernel/syscall.c:52 el0_svc_common.constprop.0+0xc4/0x254 arch/arm64/kernel/syscall.c:142 do_el0_svc+0x50/0x14c arch/arm64/kernel/syscall.c:206 el0_svc+0x54/0x140 arch/arm64/kernel/entry-common.c:637 el0t_64_sync_handler+0xb8/0xc0 arch/arm64/kernel/entry-common.c:655 el0t_64_sync+0x18c/0x190 arch/arm64/kernel/entry.S:581