INFO: task syz.4.3041:16799 blocked for more than 143 seconds.
Not tainted syzkaller #0
"echo 0 > /proc/sys/kernel/hung_task_timeout_secs" disables this message.
task:syz.4.3041 state:D stack:25784 pid:16799 tgid:16798 ppid:5827 task_flags:0x400040 flags:0x00080002
Call Trace:
context_switch kernel/sched/core.c:5256 [inline]
__schedule+0x149b/0x4fd0 kernel/sched/core.c:6863
__schedule_loop kernel/sched/core.c:6945 [inline]
schedule+0x165/0x360 kernel/sched/core.c:6960
schedule_preempt_disabled+0x13/0x30 kernel/sched/core.c:7017
__mutex_lock_common kernel/locking/mutex.c:692 [inline]
__mutex_lock+0x7e6/0x1350 kernel/locking/mutex.c:776
nfsd_nl_rpc_status_get_dumpit+0xdf/0x1290 fs/nfsd/nfsctl.c:1483
genl_dumpit+0x10b/0x1b0 net/netlink/genetlink.c:1027
netlink_dump+0x6e4/0xe90 net/netlink/af_netlink.c:2325
__netlink_dump_start+0x5cb/0x7e0 net/netlink/af_netlink.c:2440
genl_family_rcv_msg_dumpit+0x1e7/0x2c0 net/netlink/genetlink.c:1076
genl_family_rcv_msg net/netlink/genetlink.c:1192 [inline]
genl_rcv_msg+0x5da/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+0x505/0x820 net/socket.c:2592
___sys_sendmsg+0x21f/0x2a0 net/socket.c:2646
__sys_sendmsg net/socket.c:2678 [inline]
__do_sys_sendmsg net/socket.c:2683 [inline]
__se_sys_sendmsg net/socket.c:2681 [inline]
__x64_sys_sendmsg+0x19b/0x260 net/socket.c:2681
do_syscall_x64 arch/x86/entry/syscall_64.c:63 [inline]
do_syscall_64+0xec/0xf80 arch/x86/entry/syscall_64.c:94
entry_SYSCALL_64_after_hwframe+0x77/0x7f
RIP: 0033:0x7fc32ed8f749
RSP: 002b:00007fc32fbc6038 EFLAGS: 00000246 ORIG_RAX: 000000000000002e
RAX: ffffffffffffffda RBX: 00007fc32efe5fa0 RCX: 00007fc32ed8f749
RDX: 0000000000000800 RSI: 0000200000000180 RDI: 0000000000000007
RBP: 00007fc32ee13f91 R08: 0000000000000000 R09: 0000000000000000
R10: 0000000000000000 R11: 0000000000000246 R12: 0000000000000000
R13: 00007fc32efe6038 R14: 00007fc32efe5fa0 R15: 00007ffd77d5a118
Showing all locks held in the system:
1 lock held by rcu_exp_gp_kthr/18:
1 lock held by khungtaskd/31:
#0: ffffffff8df41aa0 (rcu_read_lock){....}-{1:3}, at: rcu_lock_acquire include/linux/rcupdate.h:331 [inline]
#0: ffffffff8df41aa0 (rcu_read_lock){....}-{1:3}, at: rcu_read_lock include/linux/rcupdate.h:867 [inline]
#0: ffffffff8df41aa0 (rcu_read_lock){....}-{1:3}, at: debug_show_all_locks+0x2e/0x180 kernel/locking/lockdep.c:6775
3 locks held by kworker/u8:4/61:
#0: ffff88813ff29948 ((wq_completion)events_unbound#2){+.+.}-{0:0}, at: process_one_work kernel/workqueue.c:3232 [inline]
#0: ffff88813ff29948 ((wq_completion)events_unbound#2){+.+.}-{0:0}, at: process_scheduled_works+0x9b4/0x1770 kernel/workqueue.c:3340
#1: ffffc9000212fbc0 ((linkwatch_work).work){+.+.}-{0:0}, at: process_one_work kernel/workqueue.c:3233 [inline]
#1: ffffc9000212fbc0 ((linkwatch_work).work){+.+.}-{0:0}, at: process_scheduled_works+0x9ef/0x1770 kernel/workqueue.c:3340
#2: ffffffff8f312108 (rtnl_mutex){+.+.}-{4:4}, at: linkwatch_event+0xe/0x60 net/core/link_watch.c:303
3 locks held by kworker/1:2/130:
#0: ffff88813ff15948 ((wq_completion)events){+.+.}-{0:0}, at: process_one_work kernel/workqueue.c:3232 [inline]
#0: ffff88813ff15948 ((wq_completion)events){+.+.}-{0:0}, at: process_scheduled_works+0x9b4/0x1770 kernel/workqueue.c:3340
#1: ffffc90002e97bc0 ((work_completion)(&tn->work)){+.+.}-{0:0}, at: process_one_work kernel/workqueue.c:3233 [inline]
#1: ffffc90002e97bc0 ((work_completion)(&tn->work)){+.+.}-{0:0}, at: process_scheduled_works+0x9ef/0x1770 kernel/workqueue.c:3340
#2: ffffffff8f312108 (rtnl_mutex){+.+.}-{4:4}, at: tipc_net_finalize_work+0x1e/0x90 net/tipc/net.c:148
3 locks held by kworker/u8:8/1135:
4 locks held by kworker/u8:10/1327:
2 locks held by getty/5589:
#0: ffff888034d4d0a0 (&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+0x449/0x1460 drivers/tty/n_tty.c:2211
3 locks held by kworker/u8:14/6035:
#0: ffff88814d301948 ((wq_completion)ipv6_addrconf){+.+.}-{0:0}, at: process_one_work kernel/workqueue.c:3232 [inline]
#0: ffff88814d301948 ((wq_completion)ipv6_addrconf){+.+.}-{0:0}, at: process_scheduled_works+0x9b4/0x1770 kernel/workqueue.c:3340
#1: ffffc900052b7bc0 ((work_completion)(&(&ifa->dad_work)->work)){+.+.}-{0:0}, at: process_one_work kernel/workqueue.c:3233 [inline]
#1: ffffc900052b7bc0 ((work_completion)(&(&ifa->dad_work)->work)){+.+.}-{0:0}, at: process_scheduled_works+0x9ef/0x1770 kernel/workqueue.c:3340
#2: ffffffff8f312108 (rtnl_mutex){+.+.}-{4:4}, at: rtnl_net_lock include/linux/rtnetlink.h:130 [inline]
#2: ffffffff8f312108 (rtnl_mutex){+.+.}-{4:4}, at: addrconf_dad_work+0x112/0x14b0 net/ipv6/addrconf.c:4194
2 locks held by syz.0.2418/14413:
1 lock held by udevd/16325:
#0: ffff88814235d358 (&disk->open_mutex){+.+.}-{4:4}, at: bdev_open+0xe0/0xd30 block/bdev.c:962
3 locks held by syz.4.3041/16799:
#0: ffffffff8f379e70 (cb_lock){++++}-{4:4}, at: genl_rcv+0x19/0x40 net/netlink/genetlink.c:1218
#1:
ffff88802b2566f0
(nlk_cb_mutex-GENERIC){+.+.}-{4:4}, at: __netlink_dump_start+0xfe/0x7e0 net/netlink/af_netlink.c:2404
#2: ffffffff8e2379a8 (nfsd_mutex){+.+.}-{4:4}, at: nfsd_nl_rpc_status_get_dumpit+0xdf/0x1290 fs/nfsd/nfsctl.c:1483
2 locks held by syz.6.3533/18571:
#0: ffffffff8f379e70 (cb_lock){++++}-{4:4}, at: genl_rcv+0x19/0x40 net/netlink/genetlink.c:1218
#1: ffffffff8e2379a8 (nfsd_mutex
){+.+.}-{4:4}
, at: nfsd_nl_listener_get_doit+0x10a/0x5e0 fs/nfsd/nfsctl.c:2036
2 locks held by syz.2.4050/20474:
#0:
ffffffff8f312108
(rtnl_mutex){+.+.}-{4:4}, at: tun_detach drivers/net/tun.c:634 [inline]
(rtnl_mutex){+.+.}-{4:4}, at: tun_chr_close+0x3e/0x1c0 drivers/net/tun.c:3436
#1: ffffffff8df475f8 (rcu_state.exp_mutex){+.+.}-{4:4}, at: exp_funnel_lock kernel/rcu/tree_exp.h:311 [inline]
#1: ffffffff8df475f8 (rcu_state.exp_mutex){+.+.}-{4:4}, at: synchronize_rcu_expedited+0x2b1/0x6e0 kernel/rcu/tree_exp.h:956
1 lock held by syz.3.4053/20485:
#0: ffffffff8f312108 (rtnl_mutex){+.+.}-{4:4}, at: rtnl_lock net/core/rtnetlink.c:80 [inline]
#0: ffffffff8f312108 (rtnl_mutex){+.+.}-{4:4}, at: rtnl_nets_lock net/core/rtnetlink.c:341 [inline]
#0: ffffffff8f312108 (rtnl_mutex){+.+.}-{4:4}, at: rtnl_newlink+0x8ec/0x1c90 net/core/rtnetlink.c:4071
1 lock held by syz.7.4057/20504:
#0: ffffffff8f312108 (rtnl_mutex
){+.+.}-{4:4}
, at: __tun_chr_ioctl+0x37a/0x1df0 drivers/net/tun.c:3078
1 lock held by syz.7.4057/20506:
#0:
ffffffff8f312108
(
rtnl_mutex){+.+.}-{4:4}, at: __tun_chr_ioctl+0x37a/0x1df0 drivers/net/tun.c:3078
1 lock held by syz.1.4062/20522:
#0: ffffffff8f312108 (rtnl_mutex){+.+.}-{4:4}, at: rtnl_net_lock include/linux/rtnetlink.h:130 [inline]
#0: ffffffff8f312108 (rtnl_mutex){+.+.}-{4:4}, at: devinet_ioctl+0x323/0x1b20 net/ipv4/devinet.c:1120
2 locks held by syz.5.4063/20520:
#0: ffffffff8f379e70 (cb_lock){++++}-{4:4}, at: genl_rcv+0x19/0x40 net/netlink/genetlink.c:1218
#1: ffffffff8f312108 (rtnl_mutex){+.+.}-{4:4}, at: nl80211_pre_doit+0x5f/0x930 net/wireless/nl80211.c:17932
=============================================
NMI backtrace for cpu 0
CPU: 0 UID: 0 PID: 31 Comm: khungtaskd Not tainted syzkaller #0 PREEMPT(full)
Hardware name: Google Google Compute Engine/Google Compute Engine, BIOS Google 10/25/2025
Call Trace:
dump_stack_lvl+0xe8/0x150 lib/dump_stack.c:120
nmi_cpu_backtrace+0x274/0x2d0 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]
__sys_info lib/sys_info.c:157 [inline]
sys_info+0x135/0x170 lib/sys_info.c:165
check_hung_uninterruptible_tasks kernel/hung_task.c:346 [inline]
watchdog+0xf95/0xfe0 kernel/hung_task.c:515
kthread+0x711/0x8a0 kernel/kthread.c:463
ret_from_fork+0x510/0xa50 arch/x86/kernel/process.c:158
ret_from_fork_asm+0x1a/0x30 arch/x86/entry/entry_64.S:246
Sending NMI from CPU 0 to CPUs 1:
NMI backtrace for cpu 1
CPU: 1 UID: 0 PID: 1327 Comm: kworker/u8:10 Not tainted syzkaller #0 PREEMPT(full)
Hardware name: Google Google Compute Engine/Google Compute Engine, BIOS Google 10/25/2025
Workqueue: xprtiod xs_tcp_setup_socket
RIP: 0010:io_serial_in+0x77/0xc0 drivers/tty/serial/8250/8250_port.c:400
Code: e8 4e c7 a6 fc 44 89 f9 d3 e3 49 83 c6 40 4c 89 f0 48 c1 e8 03 42 80 3c 20 00 74 08 4c 89 f7 e8 1f ea 0c fd 41 03 1e 89 da ec <0f> b6 c0 5b 41 5c 41 5e 41 5f e9 8a 9e 42 06 cc 44 89 f9 80 e1 07
RSP: 0018:ffffc9000451f430 EFLAGS: 00000002
RAX: 1ffffffff3381600 RBX: 00000000000003fd RCX: 0000000000000000
RDX: 00000000000003fd RSI: 0000000000000000 RDI: 0000000000000020
RBP: ffffffff99c0b550 R08: ffff888141338237 R09: 1ffff11028267046
R10: dffffc0000000000 R11: ffffffff851a3110 R12: dffffc0000000000
R13: 0000000000000000 R14: ffffffff99c0b2c0 R15: 0000000000000000
FS: 0000000000000000(0000) GS:ffff888125f1e000(0000) knlGS:0000000000000000
CS: 0010 DS: 0000 ES: 0000 CR0: 0000000080050033
CR2: 00007f9a84330e9c CR3: 000000002a8e6000 CR4: 00000000003526f0
Call Trace:
serial_in drivers/tty/serial/8250/8250.h:128 [inline]
serial_lsr_in drivers/tty/serial/8250/8250.h:150 [inline]
wait_for_lsr+0x1a1/0x2f0 drivers/tty/serial/8250/8250_port.c:1961
fifo_wait_for_lsr drivers/tty/serial/8250/8250_port.c:3234 [inline]
serial8250_console_fifo_write drivers/tty/serial/8250/8250_port.c:3257 [inline]
serial8250_console_write+0x1301/0x1b60 drivers/tty/serial/8250/8250_port.c:3342
console_emit_next_record kernel/printk/printk.c:3129 [inline]
console_flush_one_record kernel/printk/printk.c:3215 [inline]
console_flush_all+0x713/0xb00 kernel/printk/printk.c:3289
__console_flush_and_unlock kernel/printk/printk.c:3319 [inline]
console_unlock+0xbb/0x190 kernel/printk/printk.c:3359
vprintk_emit+0x47b/0x550 kernel/printk/printk.c:2426
_printk+0xcf/0x120 kernel/printk/printk.c:2451
xs_tcp_setup_socket+0xa64/0xc10 net/sunrpc/xprtsock.c:2491
process_one_work kernel/workqueue.c:3257 [inline]
process_scheduled_works+0xad1/0x1770 kernel/workqueue.c:3340
worker_thread+0x8a0/0xda0 kernel/workqueue.c:3421
kthread+0x711/0x8a0 kernel/kthread.c:463
ret_from_fork+0x510/0xa50 arch/x86/kernel/process.c:158
ret_from_fork_asm+0x1a/0x30 arch/x86/entry/entry_64.S:246