INFO: task syz.9.3830:22645 blocked for more than 143 seconds.
Tainted: G L syzkaller #0
"echo 0 > /proc/sys/kernel/hung_task_timeout_secs" disables this message.
task:syz.9.3830 state:D stack:25304 pid:22645 tgid:22641 ppid:12676 task_flags:0x400140 flags:0x00080002
Call Trace:
context_switch kernel/sched/core.c:5510 [inline]
__schedule+0x125c/0x6740 kernel/sched/core.c:7239
__schedule_loop kernel/sched/core.c:7316 [inline]
schedule+0xdd/0x2c0 kernel/sched/core.c:7331
schedule_preempt_disabled+0x13/0x30 kernel/sched/core.c:7388
__mutex_lock_common kernel/locking/mutex.c:726 [inline]
__mutex_lock+0xcbf/0x1bc0 kernel/locking/mutex.c:821
write_ports+0xa5/0xcc0 fs/nfsd/nfsctl.c:860
nfsctl_transaction_write+0x106/0x1a0 fs/nfsd/nfsctl.c:112
vfs_write+0x2aa/0x1050 fs/read_write.c:685
ksys_write+0x12a/0x250 fs/read_write.c:739
do_syscall_x64 arch/x86/entry/syscall_64.c:61 [inline]
do_syscall_64+0x123/0x790 arch/x86/entry/syscall_64.c:84
entry_SYSCALL_64_after_hwframe+0x77/0x7f
RIP: 0033:0x7effa959e0d9
RSP: 002b:00007effaa3f8028 EFLAGS: 00000246 ORIG_RAX: 0000000000000001
RAX: ffffffffffffffda RBX: 00007effa9825fa0 RCX: 00007effa959e0d9
RDX: 0000000000000003 RSI: 0000200000000380 RDI: 0000000000000007
RBP: 00007effa9635024 R08: 0000000000000000 R09: 0000000000000000
R10: 0000000000000000 R11: 0000000000000246 R12: 0000000000000000
R13: 00007effa9826038 R14: 00007effa9825fa0 R15: 00007ffffdd7ea08
Showing all locks held in the system:
locks held by rcu_exp_gp_kthr/18: 3, last CPU#0:
#0: ffff88801e6e8f20 ((worker)->lock){-...}-{2:2}, at: raw_spin_rq_lock_nested kernel/sched/core.c:675 [inline]
#0: ffff88801e6e8f20 ((worker)->lock){-...}-{2:2}, at: raw_spin_rq_lock_nested+0x88/0x140 kernel/sched/core.c:659
#1: ffff8880b8424568 (psi_seq){-.-.}-{0:0}, at: psi_sched_switch kernel/sched/stats.h:218 [inline]
#1: ffff8880b8424568 (psi_seq){-.-.}-{0:0}, at: __schedule+0x2e8e/0x6740 kernel/sched/core.c:7233
#2: ffffffff9b926148 (&____s->seqcount#2){----}-{0:0}, at: clockevents_program_event+0x23e/0x820 kernel/time/clockevents.c:363
locks held by khungtaskd/30: 1, last CPU#1:
#0: ffffffff8ede9440 (rcu_read_lock){....}-{1:3}, at: rcu_lock_acquire include/linux/rcupdate.h:300 [inline]
#0: ffffffff8ede9440 (rcu_read_lock){....}-{1:3}, at: rcu_read_lock include/linux/rcupdate.h:840 [inline]
#0: ffffffff8ede9440 (rcu_read_lock){....}-{1:3}, at: debug_show_all_locks+0x3d/0x184 kernel/locking/lockdep.c:6793
locks held by getty/5350: 2, on CPU#1:
#0: ffff888033fc10a0 (&tty->ldisc_sem){++++}-{0:0}, at: tty_ldisc_ref_wait+0x24/0x80 drivers/tty/tty_ldisc.c:243
#1: ffffc9000322b2e8 (&ldata->atomic_read_lock){+.+.}-{4:4}, at: n_tty_read+0x419/0x14e0 drivers/tty/n_tty.c:2211
locks held by udevd/5619: 1, on CPU#1:
#0: ffff888028c6a350 (&disk->open_mutex){+.+.}-{4:4}, at: bdev_open+0x41a/0xe40 block/bdev.c:991
locks held by kworker/u8:12/7014: 3, on CPU#0:
#0: ffff888033eb6940 ((wq_completion)ipv6_addrconf){+.+.}-{0:0}, at: process_one_work+0x12b1/0x1940 kernel/workqueue.c:3297
#1: ffffc9000533fd08 ((work_completion)(&(&net->ipv6.addr_chk_work)->work)){+.+.}-{0:0}, at: process_one_work+0x988/0x1940 kernel/workqueue.c:3298
#2: ffffffff90c9c9c0 (rtnl_mutex){+.+.}-{4:4}, at: rtnl_net_lock include/linux/rtnetlink.h:130 [inline]
#2: ffffffff90c9c9c0 (rtnl_mutex){+.+.}-{4:4}, at: addrconf_verify_work+0x12/0x30 net/ipv6/addrconf.c:4769
locks held by kworker/u8:13/7015: 2, on CPU#0:
#0: ffff88801f3bc940 ((wq_completion)iou_exit){+.+.}-{0:0}, at: process_one_work+0x12b1/0x1940 kernel/workqueue.c:3297
#1: ffffc9000527fd08 ((work_completion)(&ctx->exit_work)){+.+.}-{0:0}, at: process_one_work+0x988/0x1940 kernel/workqueue.c:3298
locks held by syz.9.3830/22645: 3, on CPU#0:
#0: ffff88802b99d270 (&f->f_pos_lock){+.+.}-{4:4}, at: fdget_pos+0x2aa/0x380 fs/file.c:1259
#1: ffff88804d3e8460 (sb_writers#32){.+.+}-{0:0}, at: ksys_write+0x12a/0x250 fs/read_write.c:739
#2: ffffffff8f274ea0 (nfsd_mutex){+.+.}-{4:4}, at: write_ports+0xa5/0xcc0 fs/nfsd/nfsctl.c:860
locks held by syz.9.3830/22646: 3, on CPU#0:
#0: ffff88807e7c0630 (&f->f_pos_lock){+.+.}-{4:4}, at: fdget_pos+0x2aa/0x380 fs/file.c:1259
#1: ffff88804d3e8460 (sb_writers#32){.+.+}-{0:0}, at: ksys_write+0x12a/0x250 fs/read_write.c:739
#2: ffffffff8f274ea0 (nfsd_mutex){+.+.}-{4:4}, at: write_ports+0xa5/0xcc0 fs/nfsd/nfsctl.c:860
locks held by kworker/u8:29/25482: 3, on CPU#0:
#0: ffff88801c084140 ((wq_completion)events_unbound){+.+.}-{0:0}, at: process_one_work+0x12b1/0x1940 kernel/workqueue.c:3297
#1: ffffc9000540fd08 ((linkwatch_work).work){+.+.}-{0:0}, at: process_one_work+0x988/0x1940 kernel/workqueue.c:3298
#2: ffffffff90c9c9c0 (rtnl_mutex){+.+.}-{4:4}, at: linkwatch_event+0x51/0xc0 net/core/link_watch.c:313
locks held by syz.3.4779/25750: 2, on CPU#1:
#0: ffffffff90c9c9c0 (rtnl_mutex){+.+.}-{4:4}, at: tun_detach drivers/net/tun.c:634 [inline]
#0: ffffffff90c9c9c0 (rtnl_mutex){+.+.}-{4:4}, at: tun_chr_close+0x38/0x220 drivers/net/tun.c:3442
#1: ffffffff8edf4ee8 (rcu_state.exp_mutex){+.+.}-{4:4}, at: exp_funnel_lock+0x19e/0x3c0 kernel/rcu/tree_exp.h:343
locks held by syz.4.4785/25765: 1, on CPU#0:
#0: ffffffff90c9c9c0 (rtnl_mutex){+.+.}-{4:4}, at: __tun_chr_ioctl+0x23e/0x47c0 drivers/net/tun.c:3084
locks held by syz.4.4785/25767: 1, on CPU#0:
#0: ffffffff90c9c9c0 (rtnl_mutex){+.+.}-{4:4}, at: tun_detach drivers/net/tun.c:634 [inline]
#0: ffffffff90c9c9c0 (rtnl_mutex){+.+.}-{4:4}, at: tun_chr_close+0x38/0x220 drivers/net/tun.c:3442
locks held by syz.4.4785/25768: 1, on CPU#1:
#0: ffffffff90c9c9c0 (rtnl_mutex){+.+.}-{4:4}, at: rtnl_lock net/core/rtnetlink.c:80 [inline]
#0: ffffffff90c9c9c0 (rtnl_mutex){+.+.}-{4:4}, at: rtnetlink_rcv_msg+0x371/0xe90 net/core/rtnetlink.c:7082
locks held by syz.4.4785/25769: 1, on CPU#0:
#0: ffffffff90c9c9c0 (rtnl_mutex){+.+.}-{4:4}, at: rtnl_net_lock include/linux/rtnetlink.h:130 [inline]
#0: ffffffff90c9c9c0 (rtnl_mutex){+.+.}-{4:4}, at: dev_ioctl+0x331/0x10e0 net/core/dev_ioctl.c:815
locks held by syz.4.4785/25770: 1, on CPU#0:
#0: ffffffff90c9c9c0 (rtnl_mutex){+.+.}-{4:4}, at: rtnl_lock net/core/rtnetlink.c:80 [inline]
#0: ffffffff90c9c9c0 (rtnl_mutex){+.+.}-{4:4}, at: rtnetlink_rcv_msg+0x371/0xe90 net/core/rtnetlink.c:7082
locks held by syz.1.4788/25777: 1, on CPU#1:
#0: ffffffff90c9c9c0 (rtnl_mutex){+.+.}-{4:4}, at: rtnl_lock net/core/rtnetlink.c:80 [inline]
#0: ffffffff90c9c9c0 (rtnl_mutex){+.+.}-{4:4}, at: rtnetlink_rcv_msg+0x371/0xe90 net/core/rtnetlink.c:7082
=============================================
NMI backtrace for cpu 1
CPU: 1 UID: 0 PID: 30 Comm: khungtaskd Tainted: G L syzkaller #0 PREEMPT(full)
Tainted: [L]=SOFTLOCKUP
Hardware name: Google Google Compute Engine/Google Compute Engine, BIOS Google 07/16/2026
Call Trace:
__dump_stack lib/dump_stack.c:94 [inline]
dump_stack_lvl+0x100/0x190 lib/dump_stack.c:120
nmi_cpu_backtrace.cold+0x12d/0x151 lib/nmi_backtrace.c:122
nmi_trigger_cpumask_backtrace+0x21f/0x2a0 lib/nmi_backtrace.c:65
trigger_all_cpu_backtrace include/linux/nmi.h:162 [inline]
__sys_info lib/sys_info.c:157 [inline]
sys_info+0x141/0x190 lib/sys_info.c:165
check_hung_uninterruptible_tasks kernel/hung_task.c:353 [inline]
watchdog+0xcb1/0x1030 kernel/hung_task.c:561
kthread+0x373/0x450 kernel/kthread.c:436
ret_from_fork+0x730/0xd60 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: 0 Comm: swapper/0 Tainted: G L syzkaller #0 PREEMPT(full)
Tainted: [L]=SOFTLOCKUP
Hardware name: Google Google Compute Engine/Google Compute Engine, BIOS Google 07/16/2026
RIP: 0010:pv_native_safe_halt+0xf/0x20 arch/x86/kernel/paravirt.c:64
Code: 58 a8 02 e9 03 4d 03 00 0f 1f 00 90 90 90 90 90 90 90 90 90 90 90 90 90 90 90 90 f3 0f 1e fa 66 90 0f 00 2d c3 d2 2c 00 fb f4 cc cc cc cc 66 2e 0f 1f 84 00 00 00 00 00 66 90 90 90 90 90 90
RSP: 0018:ffffffff8ea07cf0 EFLAGS: 00000246
RAX: 0000000004a4fbed RBX: ffffffff8ea91500 RCX: ffffffff8bbed115
RDX: 0000000000000001 RSI: ffffffff8e3a92ac RDI: ffffffff8c602380
RBP: fffffbfff1d522a0 R08: 0000000000000001 R09: ffffed101708678d
R10: ffff8880b8433c6b R11: 0000000000000001 R12: 0000000000000000
R13: 0000000000000000 R14: 1ffffffff1d40fa2 R15: dffffc0000000000
FS: 0000000000000000(0000) GS:ffff888123bd4000(0000) knlGS:0000000000000000
CS: 0010 DS: 0000 ES: 0000 CR0: 0000000080050033
CR2: 000055558991d4e8 CR3: 000000002cc0e000 CR4: 00000000003526f0
Call Trace:
arch_safe_halt arch/x86/include/asm/paravirt.h:62 [inline]
default_idle+0x9/0x10 arch/x86/kernel/process.c:768
default_idle_call+0x6c/0xb0 kernel/sched/idle.c:122
cpuidle_idle_call kernel/sched/idle.c:199 [inline]
do_idle+0x3ae/0x5b0 kernel/sched/idle.c:355
cpu_startup_entry+0x4f/0x60 kernel/sched/idle.c:454
rest_init+0x2d3/0x2e0 init/main.c:723
start_kernel+0x48e/0x490 init/main.c:1181
x86_64_start_reservations+0x24/0x30 arch/x86/kernel/head64.c:310
x86_64_start_kernel+0x12b/0x130 arch/x86/kernel/head64.c:291
common_startup_64+0x13e/0x158