INFO: task syz.1.2025:13738 blocked for more than 143 seconds.
Not tainted syzkaller #0
"echo 0 > /proc/sys/kernel/hung_task_timeout_secs" disables this message.
task:syz.1.2025 state:D stack:25120 pid:13738 tgid:13737 ppid:5617 task_flags:0x400140 flags:0x00080002
Call Trace:
context_switch kernel/sched/core.c:5533 [inline]
__schedule+0x17db/0x58f0 kernel/sched/core.c:7284
__schedule_loop kernel/sched/core.c:7361 [inline]
schedule+0x164/0x2b0 kernel/sched/core.c:7376
schedule_preempt_disabled+0x13/0x30 kernel/sched/core.c:7433
__mutex_lock_common kernel/locking/mutex.c:726 [inline]
__mutex_lock+0x7c1/0x1550 kernel/locking/mutex.c:821
nfsd_nl_version_get_doit+0x17c/0xd20 fs/nfsd/nfsctl.c:1919
genl_family_rcv_msg_doit+0x233/0x340 net/netlink/genetlink.c:1114
genl_family_rcv_msg net/netlink/genetlink.c:1194 [inline]
genl_rcv_msg+0x614/0x7a0 net/netlink/genetlink.c:1209
netlink_rcv_skb+0x226/0x4a0 net/netlink/af_netlink.c:2579
genl_rcv+0x28/0x40 net/netlink/genetlink.c:1218
netlink_unicast_kernel net/netlink/af_netlink.c:1338 [inline]
netlink_unicast+0x8ef/0xa80 net/netlink/af_netlink.c:1364
netlink_sendmsg+0x813/0xb40 net/netlink/af_netlink.c:1923
sock_sendmsg_nosec+0x13a/0x180 net/socket.c:800
__sock_sendmsg net/socket.c:815 [inline]
____sys_sendmsg+0x54e/0x850 net/socket.c:2713
___sys_sendmsg+0x2a5/0x360 net/socket.c:2767
__sys_sendmsg net/socket.c:2799 [inline]
__do_sys_sendmsg net/socket.c:2804 [inline]
__se_sys_sendmsg net/socket.c:2802 [inline]
__x64_sys_sendmsg+0x1b1/0x290 net/socket.c:2802
do_syscall_x64 arch/x86/entry/syscall_64.c:61 [inline]
do_syscall_64+0x166/0x520 arch/x86/entry/syscall_64.c:84
entry_SYSCALL_64_after_hwframe+0x77/0x7f
RIP: 0033:0x7f041459e2d9
RSP: 002b:00007f0415518028 EFLAGS: 00000246 ORIG_RAX: 000000000000002e
RAX: ffffffffffffffda RBX: 00007f0414825fa0 RCX: 00007f041459e2d9
RDX: 0000000000000004 RSI: 0000200000000000 RDI: 0000000000000005
RBP: 00007f0414635888 R08: 0000000000000000 R09: 0000000000000000
R10: 0000000000000000 R11: 0000000000000246 R12: 0000000000000000
R13: 00007f0414826038 R14: 00007f0414825fa0 R15: 00007ffc44e92da8
Showing all locks held in the system:
locks held by khungtaskd/31: 1, last CPU#1:
#0: ffffffff8fd5c8a0 (rcu_read_lock){....}-{1:3}, at: rcu_lock_acquire include/linux/rcupdate.h:309 [inline]
#0: ffffffff8fd5c8a0 (rcu_read_lock){....}-{1:3}, at: rcu_read_lock include/linux/rcupdate.h:849 [inline]
#0: ffffffff8fd5c8a0 (rcu_read_lock){....}-{1:3}, at: debug_show_all_locks+0x2e/0x180 kernel/locking/lockdep.c:6871
locks held by getty/5372: 2, on CPU#1:
#0: ffff888036e0a0a0 (&tty->ldisc_sem){++++}-{0:0}, at: tty_ldisc_ref_wait+0x25/0x70 drivers/tty/tty_ldisc.c:243
#1: ffffc900032432e8 (&ldata->atomic_read_lock){+.+.}-{4:4}, at: n_tty_read+0x45a/0x1360 drivers/tty/n_tty.c:2211
locks held by kworker/0:16/10302: 5, last CPU#0:
#0: ffff888051fe6d40 ((wq_completion)wg-crypt-wg1#9){+.+.}-{0:0}, at: rcu_lock_acquire include/linux/rcupdate.h:309 [inline]
#0: ffff888051fe6d40 ((wq_completion)wg-crypt-wg1#9){+.+.}-{0:0}, at: rcu_read_lock include/linux/rcupdate.h:849 [inline]
#0: ffff888051fe6d40 ((wq_completion)wg-crypt-wg1#9){+.+.}-{0:0}, at: process_one_work kernel/workqueue.c:3361 [inline]
#0: ffff888051fe6d40 ((wq_completion)wg-crypt-wg1#9){+.+.}-{0:0}, at: process_scheduled_works+0x97a/0x1630 kernel/workqueue.c:3479
#1: ffffc90005e67c40 ((work_completion)(&peer->transmit_packet_work)){+.+.}-{0:0}, at: rcu_lock_acquire include/linux/rcupdate.h:309 [inline]
#1: ffffc90005e67c40 ((work_completion)(&peer->transmit_packet_work)){+.+.}-{0:0}, at: rcu_read_lock include/linux/rcupdate.h:849 [inline]
#1: ffffc90005e67c40 ((work_completion)(&peer->transmit_packet_work)){+.+.}-{0:0}, at: process_one_work kernel/workqueue.c:3361 [inline]
#1: ffffc90005e67c40 ((work_completion)(&peer->transmit_packet_work)){+.+.}-{0:0}, at: process_scheduled_works+0x97a/0x1630 kernel/workqueue.c:3479
#2: ffffffff8fd5c8a0 (rcu_read_lock){....}-{1:3}, at: local_lock_acquire include/linux/local_lock_internal.h:46 [inline]
#2: ffffffff8fd5c8a0 (rcu_read_lock){....}-{1:3}, at: process_backlog+0x3de/0x18b0 net/core/dev.c:6757
#3: ffffffff905a1708 (pool_lock){-.-.}-{2:2}, at: _raw_spin_trylock_irqsave include/linux/spinlock_api_smp.h:135 [inline]
#3: ffffffff905a1708 (pool_lock){-.-.}-{2:2}, at: stack_depot_save_flags+0x29d/0x7f0 lib/stackdepot.c:695
#4: ffffffff8fd5c8a0 (rcu_read_lock){....}-{1:3}, at: rcu_lock_acquire include/linux/rcupdate.h:309 [inline]
#4: ffffffff8fd5c8a0 (rcu_read_lock){....}-{1:3}, at: rcu_read_lock include/linux/rcupdate.h:849 [inline]
#4: ffffffff8fd5c8a0 (rcu_read_lock){....}-{1:3}, at: ip_output+0x5a/0x450 net/ipv4/ip_output.c:432
locks held by kworker/u8:10/11051: 2, last CPU#0:
#0: ffff888053f03940 ((wq_completion)wg-kex-wg1#11){+.+.}-{0:0}, at: rcu_lock_acquire include/linux/rcupdate.h:309 [inline]
#0: ffff888053f03940 ((wq_completion)wg-kex-wg1#11){+.+.}-{0:0}, at: rcu_read_lock include/linux/rcupdate.h:849 [inline]
#0: ffff888053f03940 ((wq_completion)wg-kex-wg1#11){+.+.}-{0:0}, at: process_one_work kernel/workqueue.c:3361 [inline]
#0: ffff888053f03940 ((wq_completion)wg-kex-wg1#11){+.+.}-{0:0}, at: process_scheduled_works+0x97a/0x1630 kernel/workqueue.c:3479
#1: ffffc9001b877c40 ((work_completion)(&peer->transmit_handshake_work)){+.+.}-{0:0}, at: rcu_lock_acquire include/linux/rcupdate.h:309 [inline]
#1: ffffc9001b877c40 ((work_completion)(&peer->transmit_handshake_work)){+.+.}-{0:0}, at: rcu_read_lock include/linux/rcupdate.h:849 [inline]
#1: ffffc9001b877c40 ((work_completion)(&peer->transmit_handshake_work)){+.+.}-{0:0}, at: process_one_work kernel/workqueue.c:3361 [inline]
#1: ffffc9001b877c40 ((work_completion)(&peer->transmit_handshake_work)){+.+.}-{0:0}, at: process_scheduled_works+0x97a/0x1630 kernel/workqueue.c:3479
locks held by syz.4.1416/11298: 2, on CPU#0:
#0: ffffffff912c6648 (cb_lock){++++}-{4:4}, at: genl_rcv+0x19/0x40 net/netlink/genetlink.c:1217
#1: ffffffff9009f740 (nfsd_mutex){+.+.}-{4:4}, at: nfsd_nl_listener_set_doit+0x53d/0x1ab0 fs/nfsd/nfsctl.c:2057
locks held by syz.1.2025/13738: 2, on CPU#0:
#0: ffffffff912c6648 (cb_lock){++++}-{4:4}, at: genl_rcv+0x19/0x40 net/netlink/genetlink.c:1217
#1: ffffffff9009f740 (nfsd_mutex){+.+.}-{4:4}, at: nfsd_nl_version_get_doit+0x17c/0xd20 fs/nfsd/nfsctl.c:1919
locks held by syz.5.2217/14460: 2, on CPU#1:
#0: ffffffff912c6648 (cb_lock){++++}-{4:4}, at: genl_rcv+0x19/0x40 net/netlink/genetlink.c:1217
#1: ffffffff9009f740 (nfsd_mutex){+.+.}-{4:4}, at: nfsd_nl_version_get_doit+0x17c/0xd20 fs/nfsd/nfsctl.c:1919
locks held by kworker/u8:16/15075: 3, on CPU#0:
#0: ffff888032c81140 ((wq_completion)ipv6_addrconf){+.+.}-{0:0}, at: rcu_lock_acquire include/linux/rcupdate.h:309 [inline]
#0: ffff888032c81140 ((wq_completion)ipv6_addrconf){+.+.}-{0:0}, at: rcu_read_lock include/linux/rcupdate.h:849 [inline]
#0: ffff888032c81140 ((wq_completion)ipv6_addrconf){+.+.}-{0:0}, at: process_one_work kernel/workqueue.c:3361 [inline]
#0: ffff888032c81140 ((wq_completion)ipv6_addrconf){+.+.}-{0:0}, at: process_scheduled_works+0x97a/0x1630 kernel/workqueue.c:3479
#1: ffffc90004aafc40 ((work_completion)(&(&ifa->dad_work)->work)){+.+.}-{0:0}, at: rcu_lock_acquire include/linux/rcupdate.h:309 [inline]
#1: ffffc90004aafc40 ((work_completion)(&(&ifa->dad_work)->work)){+.+.}-{0:0}, at: rcu_read_lock include/linux/rcupdate.h:849 [inline]
#1: ffffc90004aafc40 ((work_completion)(&(&ifa->dad_work)->work)){+.+.}-{0:0}, at: process_one_work kernel/workqueue.c:3361 [inline]
#1: ffffc90004aafc40 ((work_completion)(&(&ifa->dad_work)->work)){+.+.}-{0:0}, at: process_scheduled_works+0x97a/0x1630 kernel/workqueue.c:3479
#2: ffffffff91255a80 (rtnl_mutex){+.+.}-{4:4}, at: rtnl_net_lock include/linux/rtnetlink.h:134 [inline]
#2: ffffffff91255a80 (rtnl_mutex){+.+.}-{4:4}, at: addrconf_dad_work+0x116/0x15c0 net/ipv6/addrconf.c:4230
locks held by syz-executor/15124: 4, last CPU#0:
#0: ffffffff8fe36530 (dup_mmap_sem){++++}-{0:0}, at: dup_mm kernel/fork.c:1542 [inline]
#0: ffffffff8fe36530 (dup_mmap_sem){++++}-{0:0}, at: copy_mm+0x10a/0x480 kernel/fork.c:1595
#1: ffff8880528b3440 (&mm->mmap_lock){++++}-{4:4}, at: mmap_write_lock_killable include/linux/mmap_lock.h:562 [inline]
#1: ffff8880528b3440 (&mm->mmap_lock){++++}-{4:4}, at: dup_mmap+0x195/0x1dc0 mm/mmap.c:1716
#2: ffff8880232d8340 (&mm->mmap_lock/1){+.+.}-{4:4}, at: mmap_write_lock_nested include/linux/mmap_lock.h:552 [inline]
#2: ffff8880232d8340 (&mm->mmap_lock/1){+.+.}-{4:4}, at: dup_mmap+0x221/0x1dc0 mm/mmap.c:1723
#3: ffffffff8fd5c8a0 (rcu_read_lock){....}-{1:3}, at: rcu_lock_acquire include/linux/rcupdate.h:309 [inline]
#3: ffffffff8fd5c8a0 (rcu_read_lock){....}-{1:3}, at: rcu_read_lock include/linux/rcupdate.h:849 [inline]
#3: ffffffff8fd5c8a0 (rcu_read_lock){....}-{1:3}, at: __pte_offset_map+0x29/0x240 mm/pgtable-generic.c:290
locks held by syz-executor/16935: 1, on CPU#0:
#0: ffffffff8fc110e0 (sched_map-wait-type-override){+.+.}-{3:3}, at: raw_spin_rq_lock_nested+0x2d/0x160 kernel/sched/core.c:677
locks held by umount/18557: 2, last CPU#1:
#0: ffff88807f9060e8 (&type->s_umount_key#32){++++}-{4:4}, at: __super_lock fs/super.c:60 [inline]
#0: ffff88807f9060e8 (&type->s_umount_key#32){++++}-{4:4}, at: __super_lock_excl fs/super.c:75 [inline]
#0: ffff88807f9060e8 (&type->s_umount_key#32){++++}-{4:4}, at: deactivate_super+0xac/0xe0 fs/super.c:613
#1: ffffffff9058d4c0 (fill_pool_map-wait-type-override){+.+.}-{3:3}, at: debug_objects_fill_pool lib/debugobjects.c:779 [inline]
#1: ffffffff9058d4c0 (fill_pool_map-wait-type-override){+.+.}-{3:3}, at: debug_object_activate+0x364/0x420 lib/debugobjects.c:869
locks held by syz.2.3166/18603: 2, last CPU#0:
#0: ffff888077f4d900 (&mm->mmap_lock){++++}-{4:4}, at: mmap_read_lock include/linux/mmap_lock.h:600 [inline]
#0: ffff888077f4d900 (&mm->mmap_lock){++++}-{4:4}, at: exit_mmap+0x1a4/0x9f0 mm/mmap.c:1299
#1: ffffffff8fd5c8a0 (rcu_read_lock){....}-{1:3}, at: rcu_lock_acquire include/linux/rcupdate.h:309 [inline]
#1: ffffffff8fd5c8a0 (rcu_read_lock){....}-{1:3}, at: rcu_read_lock include/linux/rcupdate.h:849 [inline]
#1: ffffffff8fd5c8a0 (rcu_read_lock){....}-{1:3}, at: __pte_offset_map+0x29/0x240 mm/pgtable-generic.c:290
locks held by syz.3.3169/18605: 2, last CPU#0:
#0: ffffffff91255a80 (rtnl_mutex){+.+.}-{4:4}, at: __tun_chr_ioctl+0x3da/0x1e70 drivers/net/tun.c:3234
#1: ffffffff8fd5c8a0 (rcu_read_lock){....}-{1:3}, at: rcu_lock_acquire include/linux/rcupdate.h:309 [inline]
#1: ffffffff8fd5c8a0 (rcu_read_lock){....}-{1:3}, at: rcu_read_lock include/linux/rcupdate.h:849 [inline]
#1: ffffffff8fd5c8a0 (rcu_read_lock){....}-{1:3}, at: class_rcu_constructor include/linux/rcupdate.h:1216 [inline]
#1: ffffffff8fd5c8a0 (rcu_read_lock){....}-{1:3}, at: is_module_text_address+0x1d/0x1e0 kernel/module/main.c:3938
=============================================
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 07/24/2026
Call Trace:
dump_stack_lvl+0xe8/0x150 lib/dump_stack.c:120
nmi_cpu_backtrace+0x274/0x2d0 lib/nmi_backtrace.c:123
nmi_trigger_cpumask_backtrace+0x17d/0x390 lib/nmi_backtrace.c:66
trigger_all_cpu_backtrace include/linux/nmi.h:164 [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:353 [inline]
watchdog+0xfd7/0x1030 kernel/hung_task.c:561
kthread+0x38b/0x480 kernel/kthread.c:436
ret_from_fork+0x514/0xb70 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: 18605 Comm: syz.3.3169 Not tainted syzkaller #0 PREEMPT(full)
Hardware name: Google Google Compute Engine/Google Compute Engine, BIOS Google 07/24/2026
RIP: 0010:native_save_fl arch/x86/include/asm/irqflags.h:26 [inline]
RIP: 0010:arch_local_save_flags arch/x86/include/asm/irqflags.h:109 [inline]
RIP: 0010:check_preemption_disabled+0x26/0xd0 lib/smp_processor_id.c:19
Code: 90 90 90 90 55 41 57 41 56 53 65 8b 05 db 5c ad 08 65 48 8b 0d ab 5c ad 08 85 c9 74 0c 5b 41 5e 41 5f 5d c3 cc cc cc cc cc 9c <59> f7 c1 00 02 00 00 74 ea 65 4c 8b 3d 81 5c ad 08 41 f6 47 2f 04
RSP: 0018:ffffc900074076a8 EFLAGS: 00000046
RAX: 0000000000000000 RBX: 00000000ffffffff RCX: 8000000000000000
RDX: 0000000000000002 RSI: ffffffff8e483baf RDI: ffffffff8c6dd880
RBP: 00000000ffffffff R08: ffffffff827a380c R09: 0000000000000000
R10: dffffc0000000000 R11: ffffed1003a5a925 R12: 0000000000000246
R13: ffff88804dea9f40 R14: ffffffff8fd5c8a0 R15: ffff888040435e10
FS: 00007fdbfcc746c0(0000) GS:ffff888123abf000(0000) knlGS:0000000000000000
CS: 0010 DS: 0000 ES: 0000 CR0: 0000000080050033
CR2: 000000110c303e29 CR3: 00000000573c2000 CR4: 00000000003526f0
Call Trace:
lockdep_recursion_inc kernel/locking/lockdep.c:465 [inline]
lock_is_held_type+0x5a/0x150 kernel/locking/lockdep.c:6015
kernfs_root+0xf6/0x230 fs/kernfs/kernfs-internal.h:77
kernfs_root_is_locked fs/kernfs/kernfs-internal.h:110 [inline]
kernfs_rcu_name fs/kernfs/kernfs-internal.h:120 [inline]
kernfs_sd_compare fs/kernfs/dir.c:366 [inline]
kernfs_link_sibling+0xed/0x5a0 fs/kernfs/dir.c:397
kernfs_add_one+0x2db/0x6f0 fs/kernfs/dir.c:844
__kernfs_create_file+0x22b/0x2e0 fs/kernfs/file.c:1079
sysfs_add_file_mode_ns+0x237/0x300 fs/sysfs/file.c:316
create_files fs/sysfs/group.c:82 [inline]
internal_create_group+0x679/0x1180 fs/sysfs/group.c:189
internal_create_groups fs/sysfs/group.c:229 [inline]
sysfs_create_groups+0x59/0x120 fs/sysfs/group.c:255
device_add_groups drivers/base/core.c:2911 [inline]
device_add_attrs+0x1b1/0x600 drivers/base/core.c:2986
device_add+0x488/0xb80 drivers/base/core.c:3715
netdev_register_kobject+0x197/0x350 net/core/net-sysfs.c:2340
register_netdevice+0x1433/0x1eb0 net/core/dev.c:11549
tun_set_iff+0x82b/0xf20 drivers/net/tun.c:2961
__tun_chr_ioctl+0x7e5/0x1e70 drivers/net/tun.c:3244
vfs_ioctl fs/ioctl.c:51 [inline]
__do_sys_ioctl fs/ioctl.c:597 [inline]
__se_sys_ioctl+0xfc/0x170 fs/ioctl.c:583
do_syscall_x64 arch/x86/entry/syscall_64.c:61 [inline]
do_syscall_64+0x166/0x520 arch/x86/entry/syscall_64.c:84
entry_SYSCALL_64_after_hwframe+0x77/0x7f
RIP: 0033:0x7fdbfbd9e2d9
Code: ff c3 66 2e 0f 1f 84 00 00 00 00 00 0f 1f 44 00 00 48 89 f8 48 89 f7 48 89 d6 48 89 ca 4d 89 c2 4d 89 c8 4c 8b 4c 24 08 0f 05 <48> 3d 01 f0 ff ff 73 01 c3 48 c7 c1 e8 ff ff ff f7 d8 64 89 01 48
RSP: 002b:00007fdbfcc74028 EFLAGS: 00000246 ORIG_RAX: 0000000000000010
RAX: ffffffffffffffda RBX: 00007fdbfc025fa0 RCX: 00007fdbfbd9e2d9
RDX: 0000200000000200 RSI: 00000000400454ca RDI: 0000000000000004
RBP: 00007fdbfbe35888 R08: 0000000000000000 R09: 0000000000000000
R10: 0000000000000000 R11: 0000000000000246 R12: 0000000000000000
R13: 00007fdbfc026038 R14: 00007fdbfc025fa0 R15: 00007ffc2c6544d8