INFO: task syz.0.2196:15699 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.0.2196 state:D stack:29000 pid:15699 tgid:15697 ppid:5827 task_flags:0x400140 flags:0x00080002
Call Trace:
context_switch kernel/sched/core.c:5298 [inline]
__schedule+0xfee/0x6120 kernel/sched/core.c:6911
__schedule_loop kernel/sched/core.c:6993 [inline]
schedule+0xdd/0x390 kernel/sched/core.c:7008
schedule_preempt_disabled+0x13/0x30 kernel/sched/core.c:7065
__mutex_lock_common kernel/locking/mutex.c:692 [inline]
__mutex_lock+0xc9a/0x1b90 kernel/locking/mutex.c:776
nfsd_shutdown_threads+0x5b/0xf0 fs/nfsd/nfssvc.c:576
nfsd_umount+0x3b/0x60 fs/nfsd/nfsctl.c:1364
deactivate_locked_super+0xc1/0x1b0 fs/super.c:476
deactivate_super fs/super.c:509 [inline]
deactivate_super+0xe7/0x110 fs/super.c:505
cleanup_mnt+0x21f/0x450 fs/namespace.c:1312
task_work_run+0x150/0x240 kernel/task_work.c:233
resume_user_mode_work include/linux/resume_user_mode.h:50 [inline]
__exit_to_user_mode_loop kernel/entry/common.c:67 [inline]
exit_to_user_mode_loop+0x100/0x4a0 kernel/entry/common.c:98
__exit_to_user_mode_prepare include/linux/irq-entry-common.h:226 [inline]
syscall_exit_to_user_mode_prepare include/linux/irq-entry-common.h:256 [inline]
syscall_exit_to_user_mode include/linux/entry-common.h:325 [inline]
do_syscall_64+0x668/0xf80 arch/x86/entry/syscall_64.c:100
entry_SYSCALL_64_after_hwframe+0x77/0x7f
RIP: 0033:0x7f5e4e79c799
RSP: 002b:00007f5e4c9f6028 EFLAGS: 00000246 ORIG_RAX: 00000000000000a6
RAX: 0000000000000000 RBX: 00007f5e4ea15fa0 RCX: 00007f5e4e79c799
RDX: 0000000000000000 RSI: 000000000000000c RDI: 0000200000000040
RBP: 00007f5e4e832c99 R08: 0000000000000000 R09: 0000000000000000
R10: 0000000000000000 R11: 0000000000000246 R12: 0000000000000000
R13: 00007f5e4ea16038 R14: 00007f5e4ea15fa0 R15: 00007ffefa615098
Showing all locks held in the system:
1 lock held by khungtaskd/30:
#0: ffffffff8e7e7660 (rcu_read_lock){....}-{1:3}, at: rcu_lock_acquire include/linux/rcupdate.h:312 [inline]
#0: ffffffff8e7e7660 (rcu_read_lock){....}-{1:3}, at: rcu_read_lock include/linux/rcupdate.h:850 [inline]
#0: ffffffff8e7e7660 (rcu_read_lock){....}-{1:3}, at: debug_show_all_locks+0x3d/0x184 kernel/locking/lockdep.c:6775
5 locks held by kworker/u8:11/3031:
#0: ffff88801c6ae948 ((wq_completion)netns){+.+.}-{0:0}, at: process_one_work+0x1310/0x19a0 kernel/workqueue.c:3251
#1: ffffc9000f4f7d08 (net_cleanup_work){+.+.}-{0:0}, at: process_one_work+0x988/0x19a0 kernel/workqueue.c:3252
#2: ffffffff905fbd90 (pernet_ops_rwsem){++++}-{4:4}, at: cleanup_net+0xb8/0x920 net/core/net_namespace.c:675
#3: ffffffff906145e8 (rtnl_mutex){+.+.}-{4:4}, at: default_device_exit_batch+0x90/0xc60 net/core/dev.c:13055
#4: ffffffff8e7f3278 (rcu_state.exp_mutex){+.+.}-{4:4}, at: exp_funnel_lock+0x19e/0x3c0 kernel/rcu/tree_exp.h:343
2 locks held by syz-executor/5828:
#0: ffff88807bb180e0 (&type->s_umount_key#52){+.+.}-{4:4}, at: __super_lock fs/super.c:58 [inline]
#0: ffff88807bb180e0 (&type->s_umount_key#52){+.+.}-{4:4}, at: __super_lock_excl fs/super.c:73 [inline]
#0: ffff88807bb180e0 (&type->s_umount_key#52){+.+.}-{4:4}, at: deactivate_super fs/super.c:508 [inline]
#0: ffff88807bb180e0 (&type->s_umount_key#52){+.+.}-{4:4}, at: deactivate_super+0xdf/0x110 fs/super.c:505
#1: ffffffff8ec583a8 (nfsd_mutex){+.+.}-{4:4}, at: nfsd_shutdown_threads+0x5b/0xf0 fs/nfsd/nfssvc.c:576
7 locks held by kworker/u8:14/12497:
#0: ffff8880b843b2e0 (&rq->__lock){-.-.}-{2:2}, at: raw_spin_rq_lock_nested kernel/sched/core.c:655 [inline]
#0: ffff8880b843b2e0 (&rq->__lock){-.-.}-{2:2}, at: raw_spin_rq_lock_nested+0x88/0x140 kernel/sched/core.c:639
#1: ffff888082538008 (&____s->seqcount#17){.-.-}-{0:0}, at: trace_find_filtered_pid kernel/trace/trace_pid.c:15 [inline]
#1: ffff888082538008 (&____s->seqcount#17){.-.-}-{0:0}, at: trace_ignore_this_task+0xbc/0x100 kernel/trace/trace_pid.c:44
#2: ffff8880365f4868 (&rtn->rds_tcp_accept_lock){+.+.}-{4:4}, at: rds_tcp_accept_one+0xb1/0xe70 net/rds/tcp_listen.c:172
#3: ffffffff9b472258 (&obj_hash[i].lock){-.-.}-{2:2}, at: debug_object_activate+0x144/0x490 lib/debugobjects.c:835
#4: ffffffff8e7e7660 (rcu_read_lock){....}-{1:3}, at: rcu_lock_acquire include/linux/rcupdate.h:312 [inline]
#4: ffffffff8e7e7660 (rcu_read_lock){....}-{1:3}, at: rcu_read_lock include/linux/rcupdate.h:850 [inline]
#4: ffffffff8e7e7660 (rcu_read_lock){....}-{1:3}, at: class_rcu_constructor include/linux/rcupdate.h:1193 [inline]
#4: ffffffff8e7e7660 (rcu_read_lock){....}-{1:3}, at: unwind_next_frame+0xbd/0x1ea0 arch/x86/kernel/unwind_orc.c:495
#5: ffff88813fffc198 (&zone->lock){..-.}-{3:3}, at: rmqueue_bulk mm/page_alloc.c:2559 [inline]
#5: ffff88813fffc198 (&zone->lock){..-.}-{3:3}, at: __rmqueue_pcplist+0x4a8/0x16f0 mm/page_alloc.c:3349
#6: ffffffff8e7e7660 (rcu_read_lock){....}-{1:3}, at: rcu_lock_acquire include/linux/rcupdate.h:312 [inline]
#6: ffffffff8e7e7660 (rcu_read_lock){....}-{1:3}, at: rcu_read_lock include/linux/rcupdate.h:850 [inline]
#6: ffffffff8e7e7660 (rcu_read_lock){....}-{1:3}, at: ip_local_deliver_finish+0x335/0x6e0 net/ipv4/ip_input.c:240
2 locks held by syz.3.1959/14789:
#0: ffffffff906c0910 (cb_lock){++++}-{4:4}, at: genl_rcv+0x19/0x40 net/netlink/genetlink.c:1217
#1: ffffffff8ec583a8 (nfsd_mutex){+.+.}-{4:4}, at: nfsd_nl_threads_set_doit+0x6c1/0xc00 fs/nfsd/nfsctl.c:1607
2 locks held by syz.0.2196/15699:
#0: ffff88803aecc0e0 (&type->s_umount_key#52){+.+.}-{4:4}, at: __super_lock fs/super.c:58 [inline]
#0: ffff88803aecc0e0 (&type->s_umount_key#52){+.+.}-{4:4}, at: __super_lock_excl fs/super.c:73 [inline]
#0: ffff88803aecc0e0 (&type->s_umount_key#52){+.+.}-{4:4}, at: deactivate_super fs/super.c:508 [inline]
#0: ffff88803aecc0e0 (&type->s_umount_key#52){+.+.}-{4:4}, at: deactivate_super+0xdf/0x110 fs/super.c:505
#1: ffffffff8ec583a8 (nfsd_mutex){+.+.}-{4:4}, at: nfsd_shutdown_threads+0x5b/0xf0 fs/nfsd/nfssvc.c:576
2 locks held by syz-executor/16124:
#0: ffff88807e6f20e0 (&type->s_umount_key#52){+.+.}-{4:4}, at: __super_lock fs/super.c:58 [inline]
#0: ffff88807e6f20e0 (&type->s_umount_key#52){+.+.}-{4:4}, at: __super_lock_excl fs/super.c:73 [inline]
#0: ffff88807e6f20e0 (&type->s_umount_key#52){+.+.}-{4:4}, at: deactivate_super fs/super.c:508 [inline]
#0: ffff88807e6f20e0 (&type->s_umount_key#52){+.+.}-{4:4}, at: deactivate_super+0xdf/0x110 fs/super.c:505
#1: ffffffff8ec583a8 (nfsd_mutex){+.+.}-{4:4}, at: nfsd_shutdown_threads+0x5b/0xf0 fs/nfsd/nfssvc.c:576
2 locks held by syz.4.2422/16575:
#0: ffffffff906c0910 (cb_lock){++++}-{4:4}, at: genl_rcv+0x19/0x40 net/netlink/genetlink.c:1217
#1: ffffffff8ec583a8 (nfsd_mutex){+.+.}-{4:4}, at: nfsd_nl_threads_set_doit+0x6c1/0xc00 fs/nfsd/nfsctl.c:1607
2 locks held by syz.5.2730/18085:
#0: ffffffff8fc23928 (mon_lock){+.+.}-{4:4}, at: mon_text_release+0x4e/0x3b0 drivers/usb/mon/mon_text.c:650
#1: ffffffff8e7f3140 (rcu_state.barrier_mutex){+.+.}-{4:4}, at: rcu_barrier+0x48/0x6d0 kernel/rcu/tree.c:3828
=============================================
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 02/12/2026
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:113
nmi_trigger_cpumask_backtrace+0x1d7/0x230 lib/nmi_backtrace.c:62
trigger_all_cpu_backtrace include/linux/nmi.h:161 [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:346 [inline]
watchdog+0xd25/0x1050 kernel/hung_task.c:515
kthread+0x370/0x450 kernel/kthread.c:436
ret_from_fork+0x754/0xd80 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: 17017 Comm: kworker/u8:27 Tainted: G L syzkaller #0 PREEMPT(full)
Tainted: [L]=SOFTLOCKUP
Hardware name: Google Google Compute Engine/Google Compute Engine, BIOS Google 02/12/2026
Workqueue: krds_cp_wq#3/0 rds_connect_worker
RIP: 0010:ipt_do_table+0xde4/0x1b00 net/ipv4/netfilter/ip_tables.c:313
Code: 01 00 00 5b 5d 41 5c 41 5d 41 5e 41 5f e9 44 5c 77 01 e8 3f bc ee f7 90 0f 0b 90 e9 e8 f6 ff ff e8 31 bc ee f7 48 8b 44 24 28 <48> 8d 78 20 48 b8 00 00 00 00 00 fc ff df 48 89 fa 48 c1 ea 03 0f
RSP: 0018:ffffc90000007828 EFLAGS: 00000246
RAX: ffff88802c564948 RBX: ffffffff90db8740 RCX: ffffffff8a195d75
RDX: ffff888057970000 RSI: ffffffff8a195faf RDI: ffffffff90db8770
RBP: 0000000000000000 R08: 0000000000000001 R09: 0000000000000000
R10: 0000000000000000 R11: 0000000000000000 R12: 00000000011fc47c
R13: 0000000000000001 R14: ffff88802c5648d8 R15: dffffc0000000000
FS: 0000000000000000(0000) GS:ffff888124349000(0000) knlGS:0000000000000000
CS: 0010 DS: 0000 ES: 0000 CR0: 0000000080050033
CR2: 00007f5bbebe92f8 CR3: 000000000e598000 CR4: 00000000003526f0
Call Trace:
iptable_mangle_hook+0x69/0x4b0 net/ipv4/netfilter/iptable_mangle.c:80
nf_hook_entry_hookfn include/linux/netfilter.h:158 [inline]
nf_hook_slow+0xbf/0x220 net/netfilter/core.c:623
nf_hook.constprop.0+0x2a6/0x750 include/linux/netfilter.h:273
NF_HOOK include/linux/netfilter.h:316 [inline]
ip_local_deliver+0x163/0x1f0 net/ipv4/ip_input.c:262
dst_input include/net/dst.h:480 [inline]
ip_rcv_finish net/ipv4/ip_input.c:453 [inline]
NF_HOOK include/linux/netfilter.h:318 [inline]
NF_HOOK include/linux/netfilter.h:312 [inline]
ip_rcv+0x33a/0x3c0 net/ipv4/ip_input.c:573
__netif_receive_skb_one_core+0x197/0x1e0 net/core/dev.c:6164
__netif_receive_skb+0x1f/0x120 net/core/dev.c:6277
process_backlog+0x37a/0x1580 net/core/dev.c:6628
__napi_poll.constprop.0+0xaf/0x450 net/core/dev.c:7692
napi_poll net/core/dev.c:7755 [inline]
net_rx_action+0xa40/0xf20 net/core/dev.c:7912
handle_softirqs+0x1eb/0x9e0 kernel/softirq.c:622
do_softirq kernel/softirq.c:523 [inline]
do_softirq+0xac/0xe0 kernel/softirq.c:510
__local_bh_enable_ip+0xf8/0x120 kernel/softirq.c:450
local_bh_enable include/linux/bottom_half.h:33 [inline]
rcu_read_unlock_bh include/linux/rcupdate.h:924 [inline]
__dev_queue_xmit+0x8b5/0x4800 net/core/dev.c:4873
dev_queue_xmit include/linux/netdevice.h:3385 [inline]
neigh_hh_output include/net/neighbour.h:540 [inline]
neigh_output include/net/neighbour.h:554 [inline]
ip_finish_output2+0xf4a/0x24d0 net/ipv4/ip_output.c:237
__ip_finish_output.part.0+0x444/0x6f0 net/ipv4/ip_output.c:315
__ip_finish_output net/ipv4/ip_output.c:303 [inline]
ip_finish_output net/ipv4/ip_output.c:325 [inline]
NF_HOOK_COND include/linux/netfilter.h:307 [inline]
ip_output+0x39b/0xc10 net/ipv4/ip_output.c:438
dst_output include/net/dst.h:470 [inline]
ip_local_out+0x193/0x1f0 net/ipv4/ip_output.c:131
__ip_queue_xmit+0x885/0x1e90 net/ipv4/ip_output.c:534
__tcp_transmit_skb+0x3347/0x4b50 net/ipv4/tcp_output.c:1693
tcp_transmit_skb net/ipv4/tcp_output.c:1711 [inline]
tcp_connect+0x36ab/0x5630 net/ipv4/tcp_output.c:4377
tcp_v4_connect+0x1603/0x1b40 net/ipv4/tcp_ipv4.c:346
__inet_stream_connect+0x208/0xfa0 net/ipv4/af_inet.c:685
inet_stream_connect+0x57/0xa0 net/ipv4/af_inet.c:756
kernel_connect+0x107/0x160 net/socket.c:3634
rds_tcp_conn_path_connect+0x72b/0xaa0 net/rds/tcp_connect.c:205
rds_connect_worker+0x1b4/0x2d0 net/rds/threads.c:176
process_one_work+0xa23/0x19a0 kernel/workqueue.c:3276
process_scheduled_works kernel/workqueue.c:3359 [inline]
worker_thread+0x5ef/0xe50 kernel/workqueue.c:3440
kthread+0x370/0x450 kernel/kthread.c:436
ret_from_fork+0x754/0xd80 arch/x86/kernel/process.c:158
ret_from_fork_asm+0x1a/0x30 arch/x86/entry/entry_64.S:245