INFO: task syz.2.4016:21834 blocked for more than 143 seconds.
Not tainted syzkaller #0
"echo 0 > /proc/sys/kernel/hung_task_timeout_secs" disables this message.
task:syz.2.4016 state:D stack:25408 pid:21834 tgid:21833 ppid:17709 task_flags:0x400140 flags:0x00080002
Call Trace:
context_switch kernel/sched/core.c:5325 [inline]
__schedule+0x1798/0x4cc0 kernel/sched/core.c:6929
__schedule_loop kernel/sched/core.c:7011 [inline]
schedule+0x165/0x360 kernel/sched/core.c:7026
schedule_preempt_disabled+0x13/0x30 kernel/sched/core.c:7083
__mutex_lock_common kernel/locking/mutex.c:676 [inline]
__mutex_lock+0x7e6/0x1350 kernel/locking/mutex.c:760
nfsd_nl_version_get_doit+0x16e/0xb60 fs/nfsd/nfsctl.c:1805
genl_family_rcv_msg_doit+0x215/0x300 net/netlink/genetlink.c:1115
genl_family_rcv_msg net/netlink/genetlink.c:1195 [inline]
genl_rcv_msg+0x60e/0x790 net/netlink/genetlink.c:1210
netlink_rcv_skb+0x208/0x470 net/netlink/af_netlink.c:2550
genl_rcv+0x28/0x40 net/netlink/genetlink.c:1219
netlink_unicast_kernel net/netlink/af_netlink.c:1318 [inline]
netlink_unicast+0x82f/0x9e0 net/netlink/af_netlink.c:1344
netlink_sendmsg+0x805/0xb30 net/netlink/af_netlink.c:1894
sock_sendmsg_nosec net/socket.c:727 [inline]
__sock_sendmsg+0x21c/0x270 net/socket.c:742
____sys_sendmsg+0x505/0x830 net/socket.c:2630
___sys_sendmsg+0x21f/0x2a0 net/socket.c:2684
__sys_sendmsg net/socket.c:2716 [inline]
__do_sys_sendmsg net/socket.c:2721 [inline]
__se_sys_sendmsg net/socket.c:2719 [inline]
__x64_sys_sendmsg+0x19b/0x260 net/socket.c:2719
do_syscall_x64 arch/x86/entry/syscall_64.c:63 [inline]
do_syscall_64+0xfa/0xfa0 arch/x86/entry/syscall_64.c:94
entry_SYSCALL_64_after_hwframe+0x77/0x7f
RIP: 0033:0x7f285eb8efc9
RSP: 002b:00007f285fb04038 EFLAGS: 00000246 ORIG_RAX: 000000000000002e
RAX: ffffffffffffffda RBX: 00007f285ede5fa0 RCX: 00007f285eb8efc9
RDX: 0000000000008800 RSI: 00002000000001c0 RDI: 000000000000000b
RBP: 00007f285ec11f91 R08: 0000000000000000 R09: 0000000000000000
R10: 0000000000000000 R11: 0000000000000246 R12: 0000000000000000
R13: 00007f285ede6038 R14: 00007f285ede5fa0 R15: 00007ffcdd83afe8
Showing all locks held in the system:
1 lock held by khungtaskd/31:
#0: ffffffff8e13d2e0 (rcu_read_lock){....}-{1:3}, at: rcu_lock_acquire include/linux/rcupdate.h:331 [inline]
#0: ffffffff8e13d2e0 (rcu_read_lock){....}-{1:3}, at: rcu_read_lock include/linux/rcupdate.h:867 [inline]
#0: ffffffff8e13d2e0 (rcu_read_lock){....}-{1:3}, at: debug_show_all_locks+0x2e/0x180 kernel/locking/lockdep.c:6775
2 locks held by getty/5589:
#0: ffff88814d07e0a0 (&tty->ldisc_sem){++++}-{0:0}, at: tty_ldisc_ref_wait+0x25/0x70 drivers/tty/tty_ldisc.c:243
#1: ffffc9000332b2f0 (&ldata->atomic_read_lock){+.+.}-{4:4}, at: n_tty_read+0x43e/0x1400 drivers/tty/n_tty.c:2222
3 locks held by kworker/u9:4/5836:
#0: ffff888051b5e948 ((wq_completion)hci7){+.+.}-{0:0}, at: process_one_work kernel/workqueue.c:3238 [inline]
#0: ffff888051b5e948 ((wq_completion)hci7){+.+.}-{0:0}, at: process_scheduled_works+0x9b4/0x17b0 kernel/workqueue.c:3346
#1: ffffc900041bfba0 ((work_completion)(&hdev->cmd_sync_work)){+.+.}-{0:0}, at: process_one_work kernel/workqueue.c:3239 [inline]
#1: ffffc900041bfba0 ((work_completion)(&hdev->cmd_sync_work)){+.+.}-{0:0}, at: process_scheduled_works+0x9ef/0x17b0 kernel/workqueue.c:3346
#2: ffff88805e2d0dc8 (&hdev->req_lock){+.+.}-{4:4}, at: hci_cmd_sync_work+0x1d4/0x3a0 net/bluetooth/hci_sync.c:331
2 locks held by syz.3.3827/21122:
#0: ffffffff8f5459b0 (cb_lock){++++}-{4:4}, at: genl_rcv+0x19/0x40 net/netlink/genetlink.c:1218
#1: ffffffff8e426b68 (nfsd_mutex){+.+.}-{4:4}, at: nfsd_nl_listener_set_doit+0x137/0x1690 fs/nfsd/nfsctl.c:1880
2 locks held by syz.2.4016/21834:
#0: ffffffff8f5459b0 (cb_lock){++++}-{4:4}, at: genl_rcv+0x19/0x40 net/netlink/genetlink.c:1218
#1: ffffffff8e426b68 (nfsd_mutex){+.+.}-{4:4}, at: nfsd_nl_version_get_doit+0x16e/0xb60 fs/nfsd/nfsctl.c:1805
2 locks held by syz.0.4191/22526:
#0: ffffffff8f5459b0 (cb_lock){++++}-{4:4}, at: genl_rcv+0x19/0x40 net/netlink/genetlink.c:1218
#1: ffffffff8e426b68 (nfsd_mutex){+.+.}-{4:4}, at: nfsd_nl_listener_set_doit+0x137/0x1690 fs/nfsd/nfsctl.c:1880
2 locks held by syz.1.4340/23120:
#0: ffffffff8f5459b0 (cb_lock){++++}-{4:4}, at: genl_rcv+0x19/0x40 net/netlink/genetlink.c:1218
#1: ffffffff8e426b68 (nfsd_mutex){+.+.}-{4:4}, at: nfsd_nl_listener_set_doit+0x137/0x1690 fs/nfsd/nfsctl.c:1880
2 locks held by syz.4.4608/24127:
#0: ffffffff8f5459b0 (cb_lock){++++}-{4:4}, at: genl_rcv+0x19/0x40 net/netlink/genetlink.c:1218
#1: ffffffff8e426b68 (nfsd_mutex){+.+.}-{4:4}, at: nfsd_nl_listener_set_doit+0x137/0x1690 fs/nfsd/nfsctl.c:1880
2 locks held by syz.7.4627/24188:
#0: ffffffff8f5459b0 (cb_lock){++++}-{4:4}, at: genl_rcv+0x19/0x40 net/netlink/genetlink.c:1218
#1: ffffffff8e426b68 (nfsd_mutex){+.+.}-{4:4}, at: nfsd_nl_listener_set_doit+0x137/0x1690 fs/nfsd/nfsctl.c:1880
2 locks held by syz.6.5093/26012:
#0: ffffffff8f5459b0 (cb_lock){++++}-{4:4}, at: genl_rcv+0x19/0x40 net/netlink/genetlink.c:1218
#1: ffffffff8e426b68 (nfsd_mutex){+.+.}-{4:4}, at: nfsd_nl_listener_set_doit+0x137/0x1690 fs/nfsd/nfsctl.c:1880
2 locks held by syz.8.5385/27112:
#0: ffffffff8f4dfdc8 (rtnl_mutex){+.+.}-{4:4}, at: tun_detach drivers/net/tun.c:634 [inline]
#0: ffffffff8f4dfdc8 (rtnl_mutex){+.+.}-{4:4}, at: tun_chr_close+0x3e/0x1c0 drivers/net/tun.c:3436
#1: ffffffff8e142d78 (rcu_state.exp_mutex){+.+.}-{4:4}, at: exp_funnel_lock kernel/rcu/tree_exp.h:311 [inline]
#1: ffffffff8e142d78 (rcu_state.exp_mutex){+.+.}-{4:4}, at: synchronize_rcu_expedited+0x2f6/0x730 kernel/rcu/tree_exp.h:957
1 lock held by syz.8.5385/27113:
1 lock held by syz.8.5385/27115:
=============================================
NMI backtrace for cpu 1
CPU: 1 UID: 0 PID: 31 Comm: khungtaskd Not tainted syzkaller #0 PREEMPT(full)
Hardware name: Google Google Compute Engine/Google Compute Engine, BIOS Google 10/02/2025
Call Trace:
dump_stack_lvl+0x189/0x250 lib/dump_stack.c:120
nmi_cpu_backtrace+0x39e/0x3d0 lib/nmi_backtrace.c:113
nmi_trigger_cpumask_backtrace+0x17a/0x300 lib/nmi_backtrace.c:62
trigger_all_cpu_backtrace include/linux/nmi.h:160 [inline]
check_hung_uninterruptible_tasks kernel/hung_task.c:332 [inline]
watchdog+0xf60/0xfa0 kernel/hung_task.c:495
kthread+0x711/0x8a0 kernel/kthread.c:463
ret_from_fork+0x4bc/0x870 arch/x86/kernel/process.c:158
ret_from_fork_asm+0x1a/0x30 arch/x86/entry/entry_64.S:245
Sending NMI from CPU 1 to CPUs 0:
NMI backtrace for cpu 0
CPU: 0 UID: 0 PID: 5836 Comm: kworker/u9:4 Not tainted syzkaller #0 PREEMPT(full)
Hardware name: Google Google Compute Engine/Google Compute Engine, BIOS Google 10/02/2025
Workqueue: hci7 hci_cmd_sync_work
RIP: 0010:_find_first_zero_bit+0x99/0xb0 lib/find_bit.c:149
Code: 08 45 31 ed 4d 89 f7 eb 11 49 8b 06 49 83 c7 08 49 83 c6 08 48 83 f8 ff 75 bb 49 83 c5 40 49 39 dd 73 c8 4c 89 f8 48 c1 e8 03 <42> 80 3c 20 00 74 d8 4c 89 ff e8 08 5e 96 fd eb ce 66 0f 1f 44 00
RSP: 0018:ffffc900041bf3e0 EFLAGS: 00000806
RAX: 1ffffffff26a5c82 RBX: 0000000000100000 RCX: 0000000000000001
RDX: 0000000000000001 RSI: 0000000000100000 RDI: ffffffff9352d330
RBP: 0000000000000000 R08: 0000000000000000 R09: ffffffff821a7938
R10: 0000000000000084 R11: 0000000000000000 R12: dffffc0000000000
R13: 0000000000008700 R14: ffffffff9352e410 R15: ffffffff9352e410
FS: 0000000000000000(0000) GS:ffff888125d0e000(0000) knlGS:0000000000000000
CS: 0010 DS: 0000 ES: 0000 CR0: 0000000080050033
CR2: 0000200000aca000 CR3: 000000003056e000 CR4: 00000000003526f0
Call Trace:
find_first_zero_bit include/linux/find.h:393 [inline]
alloc_lock_chain kernel/locking/lockdep.c:3714 [inline]
add_chain_cache kernel/locking/lockdep.c:3746 [inline]
lookup_chain_cache_add kernel/locking/lockdep.c:3855 [inline]
validate_chain+0x11b/0x2140 kernel/locking/lockdep.c:3876
__lock_acquire+0xab9/0xd20 kernel/locking/lockdep.c:5237
lock_acquire+0x120/0x360 kernel/locking/lockdep.c:5868
__fs_reclaim_acquire mm/page_alloc.c:4269 [inline]
fs_reclaim_acquire+0x72/0x100 mm/page_alloc.c:4283
might_alloc include/linux/sched/mm.h:318 [inline]
slab_pre_alloc_hook mm/slub.c:4906 [inline]
slab_alloc_node mm/slub.c:5241 [inline]
kmem_cache_alloc_node_noprof+0x48/0x710 mm/slub.c:5317
__alloc_skb+0x112/0x2d0 net/core/skbuff.c:660
alloc_skb include/linux/skbuff.h:1383 [inline]
mgmt_alloc_skb net/bluetooth/mgmt_util.c:64 [inline]
mgmt_send_event+0x46/0x190 net/bluetooth/mgmt_util.c:116
mgmt_connect_failed+0x39b/0x490 net/bluetooth/mgmt.c:-1
hci_conn_failed+0xda/0x310 net/bluetooth/hci_conn.c:1301
hci_abort_conn_sync+0x658/0xe30 net/bluetooth/hci_sync.c:5698
hci_cmd_sync_work+0x213/0x3a0 net/bluetooth/hci_sync.c:332
process_one_work kernel/workqueue.c:3263 [inline]
process_scheduled_works+0xae1/0x17b0 kernel/workqueue.c:3346
worker_thread+0x8a0/0xda0 kernel/workqueue.c:3427
kthread+0x711/0x8a0 kernel/kthread.c:463
ret_from_fork+0x4bc/0x870 arch/x86/kernel/process.c:158
ret_from_fork_asm+0x1a/0x30 arch/x86/entry/entry_64.S:245