INFO: task syz.1.1761:12664 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.1.1761      state:D stack:25352 pid:12664 tgid:12663 ppid:5617   task_flags:0x400140 flags:0x00080002
Call Trace:
 <TASK>
 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_unlock_export_doit+0x2ef/0x580 fs/nfsd/nfsctl.c:2724
 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: 0033:0x7f56fdf9e559
RSP: 002b:00007f56feddb028 EFLAGS: 00000246 ORIG_RAX: 000000000000002e
RAX: ffffffffffffffda RBX: 00007f56fe225fa0 RCX: 00007f56fdf9e559
RDX: 0000000004000080 RSI: 0000200000000840 RDI: 0000000000000005
RBP: 00007f56fe035ab8 R08: 0000000000000000 R09: 0000000000000000
R10: 0000000000000000 R11: 0000000000000246 R12: 0000000000000000
R13: 00007f56fe226038 R14: 00007f56fe225fa0 R15: 00007ffc508b8f68
 </TASK>

Showing all locks held in the system:
locks held by khungtaskd/33: 1, last CPU#0:
 #0: ffffffff8fd5c8e0 (rcu_read_lock){....}-{1:3}, at: rcu_lock_acquire include/linux/rcupdate.h:309 [inline]
 #0: ffffffff8fd5c8e0 (rcu_read_lock){....}-{1:3}, at: rcu_read_lock include/linux/rcupdate.h:849 [inline]
 #0: ffffffff8fd5c8e0 (rcu_read_lock){....}-{1:3}, at: debug_show_all_locks+0x2e/0x180 kernel/locking/lockdep.c:6871
locks held by kworker/0:0H/10882: 2, last CPU#0:
 #0: ffff88801c06ad40 ((wq_completion)events_highpri){+.+.}-{0:0}, at: rcu_lock_acquire include/linux/rcupdate.h:309 [inline]
 #0: ffff88801c06ad40 ((wq_completion)events_highpri){+.+.}-{0:0}, at: rcu_read_lock include/linux/rcupdate.h:849 [inline]
 #0: ffff88801c06ad40 ((wq_completion)events_highpri){+.+.}-{0:0}, at: process_one_work kernel/workqueue.c:3361 [inline]
 #0: ffff88801c06ad40 ((wq_completion)events_highpri){+.+.}-{0:0}, at: process_scheduled_works+0x97a/0x1630 kernel/workqueue.c:3479
 #1: ffffc9000c03fc40 ((work_completion)(&vmidi->output_work)){+.+.}-{0:0}, at: rcu_lock_acquire include/linux/rcupdate.h:309 [inline]
 #1: ffffc9000c03fc40 ((work_completion)(&vmidi->output_work)){+.+.}-{0:0}, at: rcu_read_lock include/linux/rcupdate.h:849 [inline]
 #1: ffffc9000c03fc40 ((work_completion)(&vmidi->output_work)){+.+.}-{0:0}, at: process_one_work kernel/workqueue.c:3361 [inline]
 #1: ffffc9000c03fc40 ((work_completion)(&vmidi->output_work)){+.+.}-{0:0}, at: process_scheduled_works+0x97a/0x1630 kernel/workqueue.c:3479
locks held by syz.2.1699/12409: 3, on CPU#0:
 #0: ffff888032c67cf0 (&f->f_pos_lock){+.+.}-{4:4}, at: fdget_pos+0x246/0x320 fs/file.c:1259
 #1: ffff88807dbac460 (sb_writers#30){.+.+}-{0:0}, at: file_start_write include/linux/fs.h:2756 [inline]
 #1: ffff88807dbac460 (sb_writers#30){.+.+}-{0:0}, at: vfs_write+0x22b/0xba0 fs/read_write.c:683
 #2: ffffffff9009f9a0 (nfsd_mutex){+.+.}-{4:4}, at: write_ports+0xb5/0xd10 fs/nfsd/nfsctl.c:867
locks held by syz-executor/12632: 4, last CPU#0:
 #0: ffffffff8fe36570 (dup_mmap_sem){++++}-{0:0}, at: dup_mm kernel/fork.c:1542 [inline]
 #0: ffffffff8fe36570 (dup_mmap_sem){++++}-{0:0}, at: copy_mm+0x10a/0x480 kernel/fork.c:1595
 #1: ffff888026544080 (&mm->mmap_lock){++++}-{4:4}, at: mmap_write_lock_killable include/linux/mmap_lock.h:562 [inline]
 #1: ffff888026544080 (&mm->mmap_lock){++++}-{4:4}, at: dup_mmap+0x195/0x1dc0 mm/mmap.c:1716
 #2: ffff8880536ba800 (&mm->mmap_lock/1){+.+.}-{4:4}, at: mmap_write_lock_nested include/linux/mmap_lock.h:552 [inline]
 #2: ffff8880536ba800 (&mm->mmap_lock/1){+.+.}-{4:4}, at: dup_mmap+0x221/0x1dc0 mm/mmap.c:1723
 #3: ffffffff8fd5c8e0 (rcu_read_lock){....}-{1:3}, at: rcu_lock_acquire include/linux/rcupdate.h:309 [inline]
 #3: ffffffff8fd5c8e0 (rcu_read_lock){....}-{1:3}, at: rcu_read_lock include/linux/rcupdate.h:849 [inline]
 #3: ffffffff8fd5c8e0 (rcu_read_lock){....}-{1:3}, at: __pte_offset_map+0x29/0x240 mm/pgtable-generic.c:290
locks held by syz.1.1761/12664: 2, on CPU#1:
 #0: ffffffff912c6988 (cb_lock){++++}-{4:4}, at: genl_rcv+0x19/0x40 net/netlink/genetlink.c:1217
 #1: ffffffff9009f9a0 (nfsd_mutex){+.+.}-{4:4}, at: nfsd_nl_unlock_export_doit+0x2ef/0x580 fs/nfsd/nfsctl.c:2724
locks held by syz.9.1791/12823: 2, on CPU#0:
 #0: ffffffff912c6988 (cb_lock){++++}-{4:4}, at: genl_rcv+0x19/0x40 net/netlink/genetlink.c:1217
 #1: ffffffff9009f9a0 (nfsd_mutex){+.+.}-{4:4}, at: nfsd_nl_unlock_export_doit+0x2ef/0x580 fs/nfsd/nfsctl.c:2724
locks held by syz-executor/14275: 6, last CPU#1:
 #0: ffffffff912c6988 (cb_lock){++++}-{4:4}, at: genl_rcv+0x19/0x40 net/netlink/genetlink.c:1217
 #1: ffffffff912c67c0 (genl_mutex){+.+.}-{4:4}, at: genl_lock net/netlink/genetlink.c:35 [inline]
 #1: ffffffff912c67c0 (genl_mutex){+.+.}-{4:4}, at: genl_op_lock net/netlink/genetlink.c:60 [inline]
 #1: ffffffff912c67c0 (genl_mutex){+.+.}-{4:4}, at: genl_rcv_msg+0x10b/0x7a0 net/netlink/genetlink.c:1208
 #2: ffffffff91255dc0 (rtnl_mutex){+.+.}-{4:4}, at: wg_set_device_doit+0x170/0x2120 drivers/net/wireguard/netlink.c:484
 #3: ffff88807e385610 (&wg->device_update_lock){+.+.}-{4:4}, at: wg_set_device_doit+0x18b/0x2120 drivers/net/wireguard/netlink.c:485
 #4: ffffffff8fe903a0 (fs_reclaim){+.+.}-{0:0}, at: might_alloc include/linux/sched/mm.h:316 [inline]
 #4: ffffffff8fe903a0 (fs_reclaim){+.+.}-{0:0}, at: slab_pre_alloc_hook mm/slub.c:4636 [inline]
 #4: ffffffff8fe903a0 (fs_reclaim){+.+.}-{0:0}, at: slab_alloc_node mm/slub.c:4974 [inline]
 #4: ffffffff8fe903a0 (fs_reclaim){+.+.}-{0:0}, at: kmem_cache_alloc_noprof+0x5f/0x600 mm/slub.c:5010
 #5: ffffffff8fea5f60 (mmu_notifier_invalidate_range_start){+.+.}-{0:0}, at: fs_reclaim_acquire+0x7c/0x100 mm/page_alloc.c:4392
locks held by getty/14295: 2, on CPU#1:
 #0: ffff888036c8a0a0 (&tty->ldisc_sem){++++}-{0:0}, at: tty_ldisc_ref_wait+0x25/0x70 drivers/tty/tty_ldisc.c:243
 #1: ffffc900055a52e8 (&ldata->atomic_read_lock){+.+.}-{4:4}, at: n_tty_read+0x45a/0x1360 drivers/tty/n_tty.c:2211
locks held by syz.4.2142/14626: 2, last CPU#1:
 #0: ffff88801d2fa460 (sb_writers#5){.+.+}-{0:0}, at: file_start_write include/linux/fs.h:2756 [inline]
 #0: ffff88801d2fa460 (sb_writers#5){.+.+}-{0:0}, at: vfs_write+0x22b/0xba0 fs/read_write.c:683
 #1: ffff88807e741aa8 (&sb->s_type->i_mutex_key#16){+.+.}-{4:4}, at: inode_lock include/linux/fs.h:1024 [inline]
 #1: ffff88807e741aa8 (&sb->s_type->i_mutex_key#16){+.+.}-{4:4}, at: shmem_file_write_iter+0x7f/0x120 mm/shmem.c:3433
locks held by syz.2.2144/14643: 2, last CPU#0:
 #0: ffff88807f784cc0 (&mm->mmap_lock){++++}-{4:4}, at: mmap_read_lock include/linux/mmap_lock.h:600 [inline]
 #0: ffff88807f784cc0 (&mm->mmap_lock){++++}-{4:4}, at: exit_mmap+0x1a4/0x9f0 mm/mmap.c:1299
 #1: ffffffff8fd5c8e0 (rcu_read_lock){....}-{1:3}, at: rcu_lock_acquire include/linux/rcupdate.h:309 [inline]
 #1: ffffffff8fd5c8e0 (rcu_read_lock){....}-{1:3}, at: rcu_read_lock include/linux/rcupdate.h:849 [inline]
 #1: ffffffff8fd5c8e0 (rcu_read_lock){....}-{1:3}, at: __pte_offset_map+0x29/0x240 mm/pgtable-generic.c:290
locks held by syz.3.2146/14648: 1, on CPU#1:
 #0: ffff8880373380e8 (&type->s_umount_key#59/1){+.+.}-{4:4}, at: alloc_super fs/super.c:351 [inline]
 #0: ffff8880373380e8 (&type->s_umount_key#59/1){+.+.}-{4:4}, at: sget_fc+0x9d4/0x1a60 fs/super.c:874
locks held by dhcpcd-run-hook/14645: 2, last CPU#1:
 #0: ffff88807442a948 (vm_lock){++++}-{0:0}, at: lock_vma_under_rcu+0x1d1/0x500 mm/mmap_lock.c:310
 #1: ffffffff8fd5c8e0 (rcu_read_lock){....}-{1:3}, at: rcu_lock_acquire include/linux/rcupdate.h:309 [inline]
 #1: ffffffff8fd5c8e0 (rcu_read_lock){....}-{1:3}, at: rcu_read_lock include/linux/rcupdate.h:849 [inline]
 #1: ffffffff8fd5c8e0 (rcu_read_lock){....}-{1:3}, at: count_memcg_events_mm include/linux/memcontrol.h:990 [inline]
 #1: ffffffff8fd5c8e0 (rcu_read_lock){....}-{1:3}, at: count_memcg_event_mm+0x21/0x260 include/linux/memcontrol.h:1000

=============================================

NMI backtrace for cpu 0
CPU: 0 UID: 0 PID: 33 Comm: khungtaskd Tainted: G             L      syzkaller #0 PREEMPT(full) 
Tainted: [L]=SOFTLOCKUP
Hardware name: Google Google Compute Engine/Google Compute Engine, BIOS Google 08/26/2026
Call Trace:
 <TASK>
 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
 </TASK>
Sending NMI from CPU 0 to CPUs 1:
NMI backtrace for cpu 1
CPU: 1 UID: 0 PID: 1167 Comm: kworker/u8:12 Tainted: G             L      syzkaller #0 PREEMPT(full) 
Tainted: [L]=SOFTLOCKUP
Hardware name: Google Google Compute Engine/Google Compute Engine, BIOS Google 08/26/2026
Workqueue: events_unbound nsim_dev_trap_report_work
RIP: 0010:trace_irq_enable+0x34/0x140 include/trace/events/preemptirq.h:40
Code: 8b 05 78 b1 c5 12 83 f8 08 73 37 89 c3 c1 e8 06 48 8d 3c c5 78 74 7a 91 be 08 00 00 00 e8 74 94 68 00 48 0f a3 1d 94 15 aa 0f <73> 09 e8 95 3f dc ff 84 c0 74 13 5b 41 5c 41 5e 41 5f e9 10 e2 3f
RSP: 0018:ffffc90004e8f810 EFLAGS: 00000057
RAX: 0000000000000001 RBX: 0000000000000001 RCX: ffffffff81d05edc
RDX: 0000000000000000 RSI: 0000000000000008 RDI: ffffffff917a7478
RBP: ffff88807797b840 R08: ffffffff917a747f R09: 1ffffffff22f4e8f
R10: dffffc0000000000 R11: fffffbfff22f4e90 R12: 0000000000000000
R13: ffff888035528000 R14: ffffffff9bbfd1e8 R15: 0000000000000000
FS:  0000000000000000(0000) GS:ffff888123bbf000(0000) knlGS:0000000000000000
CS:  0010 DS: 0000 ES: 0000 CR0: 0000000080050033
CR2: 00007f02750f7c38 CR3: 0000000042b42000 CR4: 0000000000350ef0
Call Trace:
 <TASK>
 trace_hardirqs_on+0x18/0x40 kernel/trace/trace_preemptirq.c:73
 __raw_spin_unlock_irqrestore include/linux/spinlock_api_smp.h:210 [inline]
 _raw_spin_unlock_irqrestore+0x30/0x80 kernel/locking/spinlock.c:221
 __debug_check_no_obj_freed lib/debugobjects.c:1180 [inline]
 debug_check_no_obj_freed+0x39e/0x450 lib/debugobjects.c:1201
 slab_free_hook mm/slub.c:2679 [inline]
 slab_free mm/slub.c:6509 [inline]
 kfree+0x13e/0x650 mm/slub.c:6802
 skb_kfree_head net/core/skbuff.c:1083 [inline]
 skb_free_head net/core/skbuff.c:1095 [inline]
 skb_release_data+0x82e/0xa80 net/core/skbuff.c:1122
 skb_release_all net/core/skbuff.c:1197 [inline]
 __kfree_skb+0x5d/0x210 net/core/skbuff.c:1211
 nsim_dev_trap_report drivers/net/netdevsim/dev.c:817 [inline]
 nsim_dev_trap_report_work+0x7ac/0xb40 drivers/net/netdevsim/dev.c:847
 process_one_work kernel/workqueue.c:3396 [inline]
 process_scheduled_works+0xc3d/0x1630 kernel/workqueue.c:3479
 worker_thread+0xa47/0xfb0 kernel/workqueue.c:3560
 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
 </TASK>