INFO: task syz.1.2596:16832 blocked for more than 143 seconds.
Tainted: G U syzkaller #0
"echo 0 > /proc/sys/kernel/hung_task_timeout_secs" disables this message.
task:syz.1.2596 state:D stack:27000 pid:16832 tgid:16830 ppid:16023 task_flags:0x400140 flags:0x00080002
Call Trace:
context_switch kernel/sched/core.c:5256 [inline]
__schedule+0x1139/0x6150 kernel/sched/core.c:6863
__schedule_loop kernel/sched/core.c:6945 [inline]
schedule+0xe7/0x3a0 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+0xcf8/0x1b10 kernel/locking/mutex.c:776
nfsd_nl_listener_set_doit+0xd5/0x1ae0 fs/nfsd/nfsctl.c:1880
genl_family_rcv_msg_doit+0x209/0x2f0 net/netlink/genetlink.c:1115
genl_family_rcv_msg net/netlink/genetlink.c:1195 [inline]
genl_rcv_msg+0x55c/0x800 net/netlink/genetlink.c:1210
netlink_rcv_skb+0x158/0x420 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+0x5aa/0x870 net/netlink/af_netlink.c:1344
netlink_sendmsg+0x8c8/0xdd0 net/netlink/af_netlink.c:1894
sock_sendmsg_nosec net/socket.c:718 [inline]
__sock_sendmsg net/socket.c:733 [inline]
____sys_sendmsg+0xa5d/0xc30 net/socket.c:2583
___sys_sendmsg+0x134/0x1d0 net/socket.c:2637
__sys_sendmsg+0x16d/0x220 net/socket.c:2669
do_syscall_x64 arch/x86/entry/syscall_64.c:63 [inline]
do_syscall_64+0xcd/0xf80 arch/x86/entry/syscall_64.c:94
entry_SYSCALL_64_after_hwframe+0x77/0x7f
RIP: 0033:0x7fb62df8f7c9
RSP: 002b:00007fb62ee24038 EFLAGS: 00000246 ORIG_RAX: 000000000000002e
RAX: ffffffffffffffda RBX: 00007fb62e1e5fa0 RCX: 00007fb62df8f7c9
RDX: 0000000020000000 RSI: 0000200000005380 RDI: 0000000000000003
RBP: 00007fb62e013f91 R08: 0000000000000000 R09: 0000000000000000
R10: 0000000000000000 R11: 0000000000000246 R12: 0000000000000000
R13: 00007fb62e1e6038 R14: 00007fb62e1e5fa0 R15: 00007ffe13579078
Showing all locks held in the system:
2 locks held by kworker/0:1/10:
#0: ffff8880b843acd8 (&rq->__lock){-.-.}-{2:2}, at: raw_spin_rq_lock_nested kernel/sched/core.c:647 [inline]
#0: ffff8880b843acd8 (&rq->__lock){-.-.}-{2:2}, at: raw_spin_rq_lock_nested+0x7e/0x130 kernel/sched/core.c:632
#1: ffff8880b8424508 (psi_seq){-.-.}-{0:0}, at: psi_sched_switch kernel/sched/stats.h:220 [inline]
#1: ffff8880b8424508 (psi_seq){-.-.}-{0:0}, at: __schedule+0x19b1/0x6150 kernel/sched/core.c:6857
1 lock held by khungtaskd/31:
#0: ffffffff8e3c9140 (rcu_read_lock){....}-{1:3}, at: rcu_lock_acquire include/linux/rcupdate.h:331 [inline]
#0: ffffffff8e3c9140 (rcu_read_lock){....}-{1:3}, at: rcu_read_lock include/linux/rcupdate.h:867 [inline]
#0: ffffffff8e3c9140 (rcu_read_lock){....}-{1:3}, at: debug_show_all_locks+0x36/0x1c0 kernel/locking/lockdep.c:6775
5 locks held by kworker/u8:10/2990:
#0: ffff88801badf148 ((wq_completion)netns){+.+.}-{0:0}, at: process_one_work+0x128d/0x1b20 kernel/workqueue.c:3232
#1: ffffc9000ba67c90 (net_cleanup_work){+.+.}-{0:0}, at: process_one_work+0x914/0x1b20 kernel/workqueue.c:3233
#2: ffffffff90108830 (pernet_ops_rwsem){++++}-{4:4}, at: cleanup_net+0xad/0x830 net/core/net_namespace.c:670
#3: ffffffff9011ee88 (rtnl_mutex){+.+.}-{4:4}, at: ops_exit_rtnl_list net/core/net_namespace.c:173 [inline]
#3: ffffffff9011ee88 (rtnl_mutex){+.+.}-{4:4}, at: ops_undo_list+0x7e9/0xab0 net/core/net_namespace.c:248
#4: ffffffff8e3d48b8 (rcu_state.exp_mutex){+.+.}-{4:4}, at: exp_funnel_lock+0x284/0x3c0 kernel/rcu/tree_exp.h:311
2 locks held by getty/5591:
#0: ffff88814dc3f0a0 (&tty->ldisc_sem){++++}-{0:0}, at: tty_ldisc_ref_wait+0x24/0x80 drivers/tty/tty_ldisc.c:243
#1: ffffc9000332b2f0 (&ldata->atomic_read_lock){+.+.}-{4:4}, at: n_tty_read+0x41b/0x14f0 drivers/tty/n_tty.c:2222
2 locks held by syz.3.2590/16808:
#0: ffffffff901c5310 (cb_lock){++++}-{4:4}, at: genl_rcv+0x19/0x40 net/netlink/genetlink.c:1218
#1: ffffffff8e7fd848 (nfsd_mutex){+.+.}-{4:4}, at: nfsd_nl_listener_set_doit+0xd5/0x1ae0 fs/nfsd/nfsctl.c:1880
2 locks held by syz.1.2596/16832:
#0: ffffffff901c5310 (cb_lock){++++}-{4:4}, at: genl_rcv+0x19/0x40 net/netlink/genetlink.c:1218
#1: ffffffff8e7fd848 (nfsd_mutex){+.+.}-{4:4}, at: nfsd_nl_listener_set_doit+0xd5/0x1ae0 fs/nfsd/nfsctl.c:1880
2 locks held by syz.5.2764/17581:
#0: ffffffff901c5310 (cb_lock){++++}-{4:4}, at: genl_rcv+0x19/0x40 net/netlink/genetlink.c:1218
#1: ffffffff8e7fd848 (nfsd_mutex){+.+.}-{4:4}, at: nfsd_nl_listener_set_doit+0xd5/0x1ae0 fs/nfsd/nfsctl.c:1880
2 locks held by syz.4.2817/17897:
#0: ffffffff901c5310 (cb_lock){++++}-{4:4}, at: genl_rcv+0x19/0x40 net/netlink/genetlink.c:1218
#1: ffffffff8e7fd848 (nfsd_mutex){+.+.}-{4:4}, at: nfsd_nl_listener_set_doit+0xd5/0x1ae0 fs/nfsd/nfsctl.c:1880
3 locks held by syz.8.3132/19232:
2 locks held by syz.7.3150/19296:
#0: ffff8880535263c8 (&sb->s_type->i_mutex_key#12){+.+.}-{4:4}, at: inode_lock include/linux/fs.h:1027 [inline]
#0: ffff8880535263c8 (&sb->s_type->i_mutex_key#12){+.+.}-{4:4}, at: __sock_release+0x86/0x270 net/socket.c:652
#1: ffffffff8e3d48b8 (rcu_state.exp_mutex){+.+.}-{4:4}, at: exp_funnel_lock+0x1a3/0x3c0 kernel/rcu/tree_exp.h:343
=============================================
NMI backtrace for cpu 0
CPU: 0 UID: 0 PID: 31 Comm: khungtaskd Tainted: G U syzkaller #0 PREEMPT(full)
Tainted: [U]=USER
Hardware name: Google Google Compute Engine/Google Compute Engine, BIOS Google 10/25/2025
Call Trace:
__dump_stack lib/dump_stack.c:94 [inline]
dump_stack_lvl+0x116/0x1f0 lib/dump_stack.c:120
nmi_cpu_backtrace+0x27b/0x390 lib/nmi_backtrace.c:113
nmi_trigger_cpumask_backtrace+0x29c/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+0xf14/0x1140 kernel/hung_task.c:495
kthread+0x3c5/0x780 kernel/kthread.c:463
ret_from_fork+0x983/0xb10 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: 2990 Comm: kworker/u8:10 Tainted: G U syzkaller #0 PREEMPT(full)
Tainted: [U]=USER
Hardware name: Google Google Compute Engine/Google Compute Engine, BIOS Google 10/25/2025
Workqueue: netns cleanup_net
RIP: 0010:write_comp_data+0x0/0x90 kernel/kcov.c:240
Code: 48 8b 05 7b 40 ec 11 48 8b 80 60 16 00 00 c3 cc cc cc cc 0f 1f 80 00 00 00 00 90 90 90 90 90 90 90 90 90 90 90 90 90 90 90 90 <49> 89 d2 49 89 f8 49 89 f1 65 48 8b 15 47 40 ec 11 65 8b 05 58 40
RSP: 0018:ffffc9000ba67730 EFLAGS: 00000246
RAX: 0000000000000001 RBX: ffff88805dfa1a50 RCX: ffffffff8265b6b6
RDX: 0000000000000001 RSI: 0000000000000000 RDI: 0000000000000005
RBP: ffff88805dfa1b40 R08: 0000000000000001 R09: 0000000000000000
R10: 0000000000000001 R11: 00000000c0748890 R12: 0000000000000001
R13: ffffffff8cc38400 R14: 0000000000000000 R15: 0000000000000001
FS: 0000000000000000(0000) GS:ffff888124a85000(0000) knlGS:0000000000000000
CS: 0010 DS: 0000 ES: 0000 CR0: 0000000080050033
CR2: 0000001b34ad6ff8 CR3: 000000003446c000 CR4: 00000000003526f0
Call Trace:
kernfs_root+0x86/0x2a0 fs/kernfs/kernfs-internal.h:76
kernfs_find_ns+0x366/0x530 fs/kernfs/dir.c:860
kernfs_remove_by_name_ns+0x4b/0x100 fs/kernfs/dir.c:1714
kernfs_remove_by_name include/linux/kernfs.h:633 [inline]
remove_files+0x96/0x1c0 fs/sysfs/group.c:28
sysfs_remove_group+0x8b/0x180 fs/sysfs/group.c:322
sysfs_remove_groups fs/sysfs/group.c:346 [inline]
sysfs_remove_groups+0x60/0xa0 fs/sysfs/group.c:338
netdev_queue_update_kobjects+0x4dd/0x710 net/core/net-sysfs.c:2072
remove_queue_kobjects net/core/net-sysfs.c:2170 [inline]
netdev_unregister_kobject+0x168/0x540 net/core/net-sysfs.c:2325
unregister_netdevice_many_notify+0x14f9/0x2570 net/core/dev.c:12416
ops_exit_rtnl_list net/core/net_namespace.c:187 [inline]
ops_undo_list+0x8fc/0xab0 net/core/net_namespace.c:248
cleanup_net+0x41b/0x830 net/core/net_namespace.c:696
process_one_work+0x9ba/0x1b20 kernel/workqueue.c:3257
process_scheduled_works kernel/workqueue.c:3340 [inline]
worker_thread+0x6c8/0xf10 kernel/workqueue.c:3421
kthread+0x3c5/0x780 kernel/kthread.c:463
ret_from_fork+0x983/0xb10 arch/x86/kernel/process.c:158
ret_from_fork_asm+0x1a/0x30 arch/x86/entry/entry_64.S:246