syzbot


possible deadlock in nci_close_device

Status: upstream: reported on 2024/04/03 04:08
Reported-by: syzbot+b48d4c917c8276ea9df3@syzkaller.appspotmail.com
First crash: 82d, last: 82d
Similar bugs (2)
Kernel Title Repro Cause bisect Fix bisect Count Last Reported Patched Status
upstream possible deadlock in nci_close_device net nfc 2 566d 580d 22/27 fixed on 2023/02/24 13:50
linux-5.15 possible deadlock in nci_close_device 1 260d 260d 0/3 auto-obsoleted due to no activity on 2024/01/16 04:06

Sample crash report:
======================================================
WARNING: possible circular locking dependency detected
6.1.83-syzkaller #0 Not tainted
------------------------------------------------------
kworker/0:7/3611 is trying to acquire lock:
ffff88807a488350 (&ndev->req_lock){+.+.}-{3:3}, at: nci_close_device+0x106/0x5f0 net/nfc/nci/core.c:560

but task is already holding lock:
ffffffff8e547a28 (rfkill_global_mutex){+.+.}-{3:3}, at: rfkill_sync_work+0x25/0xe0 net/rfkill/core.c:1040

which lock already depends on the new lock.


the existing dependency chain (in reverse order) is:

-> #2 (rfkill_global_mutex){+.+.}-{3:3}:
       lock_acquire+0x1f8/0x5a0 kernel/locking/lockdep.c:5662
       __mutex_lock_common kernel/locking/mutex.c:603 [inline]
       __mutex_lock+0x132/0xd80 kernel/locking/mutex.c:747
       rfkill_register+0x30/0x880 net/rfkill/core.c:1057
       nfc_register_device+0x144/0x310 net/nfc/core.c:1132
       nci_register_device+0x7be/0x900 net/nfc/nci/core.c:1265
       virtual_ncidev_open+0x55/0xc0 drivers/nfc/virtual_ncidev.c:146
       misc_open+0x304/0x380 drivers/char/misc.c:143
       chrdev_open+0x54a/0x630 fs/char_dev.c:414
       do_dentry_open+0x7f9/0x10f0 fs/open.c:882
       do_open fs/namei.c:3628 [inline]
       path_openat+0x2644/0x2e60 fs/namei.c:3785
       do_filp_open+0x230/0x480 fs/namei.c:3812
       do_sys_openat2+0x13b/0x500 fs/open.c:1318
       do_sys_open fs/open.c:1334 [inline]
       __do_sys_openat fs/open.c:1350 [inline]
       __se_sys_openat fs/open.c:1345 [inline]
       __x64_sys_openat+0x243/0x290 fs/open.c:1345
       do_syscall_x64 arch/x86/entry/common.c:51 [inline]
       do_syscall_64+0x3d/0xb0 arch/x86/entry/common.c:81
       entry_SYSCALL_64_after_hwframe+0x63/0xcd

-> #1 (nci_mutex){+.+.}-{3:3}:
       lock_acquire+0x1f8/0x5a0 kernel/locking/lockdep.c:5662
       __mutex_lock_common kernel/locking/mutex.c:603 [inline]
       __mutex_lock+0x132/0xd80 kernel/locking/mutex.c:747
       virtual_nci_close+0x13/0x40 drivers/nfc/virtual_ncidev.c:44
       nci_open_device net/nfc/nci/core.c:544 [inline]
       nci_dev_up+0x954/0xd40 net/nfc/nci/core.c:631
       nfc_dev_up+0x185/0x330 net/nfc/core.c:118
       nfc_genl_dev_up+0x80/0xd0 net/nfc/netlink.c:770
       genl_family_rcv_msg_doit net/netlink/genetlink.c:756 [inline]
       genl_family_rcv_msg net/netlink/genetlink.c:833 [inline]
       genl_rcv_msg+0xc1a/0xf70 net/netlink/genetlink.c:850
       netlink_rcv_skb+0x1cd/0x410 net/netlink/af_netlink.c:2508
       genl_rcv+0x24/0x40 net/netlink/genetlink.c:861
       netlink_unicast_kernel net/netlink/af_netlink.c:1326 [inline]
       netlink_unicast+0x7d8/0x970 net/netlink/af_netlink.c:1352
       netlink_sendmsg+0xa26/0xd60 net/netlink/af_netlink.c:1874
       sock_sendmsg_nosec net/socket.c:718 [inline]
       __sock_sendmsg net/socket.c:730 [inline]
       ____sys_sendmsg+0x5a5/0x8f0 net/socket.c:2514
       ___sys_sendmsg net/socket.c:2568 [inline]
       __sys_sendmsg+0x2a9/0x390 net/socket.c:2597
       do_syscall_x64 arch/x86/entry/common.c:51 [inline]
       do_syscall_64+0x3d/0xb0 arch/x86/entry/common.c:81
       entry_SYSCALL_64_after_hwframe+0x63/0xcd

-> #0 (&ndev->req_lock){+.+.}-{3:3}:
       check_prev_add kernel/locking/lockdep.c:3090 [inline]
       check_prevs_add kernel/locking/lockdep.c:3209 [inline]
       validate_chain+0x1661/0x5950 kernel/locking/lockdep.c:3825
       __lock_acquire+0x125b/0x1f80 kernel/locking/lockdep.c:5049
       lock_acquire+0x1f8/0x5a0 kernel/locking/lockdep.c:5662
       __mutex_lock_common kernel/locking/mutex.c:603 [inline]
       __mutex_lock+0x132/0xd80 kernel/locking/mutex.c:747
       nci_close_device+0x106/0x5f0 net/nfc/nci/core.c:560
       nci_dev_down+0x37/0x40 net/nfc/nci/core.c:638
       nfc_dev_down net/nfc/core.c:161 [inline]
       nfc_rfkill_set_block+0x16d/0x2f0 net/nfc/core.c:179
       rfkill_set_block+0x1e7/0x430 net/rfkill/core.c:345
       rfkill_sync_work+0x8a/0xe0 net/rfkill/core.c:1042
       process_one_work+0x8a9/0x11d0 kernel/workqueue.c:2292
       worker_thread+0xa47/0x1200 kernel/workqueue.c:2439
       kthread+0x28d/0x320 kernel/kthread.c:376
       ret_from_fork+0x1f/0x30 arch/x86/entry/entry_64.S:307

other info that might help us debug this:

Chain exists of:
  &ndev->req_lock --> nci_mutex --> rfkill_global_mutex

 Possible unsafe locking scenario:

       CPU0                    CPU1
       ----                    ----
  lock(rfkill_global_mutex);
                               lock(nci_mutex);
                               lock(rfkill_global_mutex);
  lock(&ndev->req_lock);

 *** DEADLOCK ***

4 locks held by kworker/0:7/3611:
 #0: ffff888012470938 ((wq_completion)events){+.+.}-{0:0}, at: process_one_work+0x7a9/0x11d0 kernel/workqueue.c:2267
 #1: ffffc9000402fd20 ((work_completion)(&rfkill->sync_work)){+.+.}-{0:0}, at: process_one_work+0x7a9/0x11d0 kernel/workqueue.c:2267
 #2: ffffffff8e547a28 (rfkill_global_mutex){+.+.}-{3:3}, at: rfkill_sync_work+0x25/0xe0 net/rfkill/core.c:1040
 #3: ffff88807aa28100 (&dev->mutex){....}-{3:3}, at: device_lock include/linux/device.h:837 [inline]
 #3: ffff88807aa28100 (&dev->mutex){....}-{3:3}, at: nfc_dev_down net/nfc/core.c:143 [inline]
 #3: ffff88807aa28100 (&dev->mutex){....}-{3:3}, at: nfc_rfkill_set_block+0x4c/0x2f0 net/nfc/core.c:179

stack backtrace:
CPU: 0 PID: 3611 Comm: kworker/0:7 Not tainted 6.1.83-syzkaller #0
Hardware name: Google Google Compute Engine/Google Compute Engine, BIOS Google 03/27/2024
Workqueue: events rfkill_sync_work
Call Trace:
 <TASK>
 __dump_stack lib/dump_stack.c:88 [inline]
 dump_stack_lvl+0x1e3/0x2cb lib/dump_stack.c:106
 check_noncircular+0x2fa/0x3b0 kernel/locking/lockdep.c:2170
 check_prev_add kernel/locking/lockdep.c:3090 [inline]
 check_prevs_add kernel/locking/lockdep.c:3209 [inline]
 validate_chain+0x1661/0x5950 kernel/locking/lockdep.c:3825
 __lock_acquire+0x125b/0x1f80 kernel/locking/lockdep.c:5049
 lock_acquire+0x1f8/0x5a0 kernel/locking/lockdep.c:5662
 __mutex_lock_common kernel/locking/mutex.c:603 [inline]
 __mutex_lock+0x132/0xd80 kernel/locking/mutex.c:747
 nci_close_device+0x106/0x5f0 net/nfc/nci/core.c:560
 nci_dev_down+0x37/0x40 net/nfc/nci/core.c:638
 nfc_dev_down net/nfc/core.c:161 [inline]
 nfc_rfkill_set_block+0x16d/0x2f0 net/nfc/core.c:179
 rfkill_set_block+0x1e7/0x430 net/rfkill/core.c:345
 rfkill_sync_work+0x8a/0xe0 net/rfkill/core.c:1042
 process_one_work+0x8a9/0x11d0 kernel/workqueue.c:2292
 worker_thread+0xa47/0x1200 kernel/workqueue.c:2439
 kthread+0x28d/0x320 kernel/kthread.c:376
 ret_from_fork+0x1f/0x30 arch/x86/entry/entry_64.S:307
 </TASK>

Crashes (1):
Time Kernel Commit Syzkaller Config Log Report Syz repro C repro VM info Assets (help?) Manager Title
2024/04/03 04:08 linux-6.1.y e5cd595e23c1 7925100d .config console log report info [disk image] [vmlinux] [kernel image] ci2-linux-6-1-kasan possible deadlock in nci_close_device
* Struck through repros no longer work on HEAD.