INFO: task syz.2.1198:10257 blocked for more than 143 seconds.
      Not tainted syzkaller #0
"echo 0 > /proc/sys/kernel/hung_task_timeout_secs" disables this message.
task:syz.2.1198      state:D stack:25696 pid:10257 tgid:10256 ppid:5616   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_cache_flush_doit+0xe2/0x1b fs/nfsd/nfsctl.c:2319
 nfsd_nl_cache_flush_doit+0xe2/0x1b0 fs/nfsd/nfsctl.c:2319
 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:2575
 genl_rcv+0x28/0x40 net/netlink/genetlink.c:1218
 netlink_unicast_kernel net/netlink/af_netlink.c:1338 [inline]
 netlink_unicast+0x7bd/0x940 net/netlink/af_netlink.c:1364
 netlink_sendmsg+0x813/0xb40 net/netlink/af_netlink.c:1919
 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: 0033:0x7fbcacb9e1d9
RSP: 002b:00007fbcaadf6028 EFLAGS: 00000246 ORIG_RAX: 000000000000002e
RAX: ffffffffffffffda RBX: 00007fbcace25fa0 RCX: 00007fbcacb9e1d9
RDX: 0000000004000880 RSI: 0000200000000080 RDI: 0000000000000005
RBP: 00007fbcacc35888 R08: 0000000000000000 R09: 0000000000000000
R10: 0000000000000000 R11: 0000000000000246 R12: 0000000000000000
R13: 00007fbcace26038 R14: 00007fbcace25fa0 R15: 00007ffe2c2eb5c8
 </TASK>

Showing all locks held in the system:
locks held by khungtaskd/33: 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#0:
 #0: ffff8880330410a0 (&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 syz-executor/5615: 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: ffff888076e18340 (&mm->mmap_lock){++++}-{4:4}, at: mmap_write_lock_killable include/linux/mmap_lock.h:562 [inline]
 #1: ffff888076e18340 (&mm->mmap_lock){++++}-{4:4}, at: dup_mmap+0x195/0x1dc0 mm/mmap.c:1716
 #2: ffff8880368f8f80 (&mm->mmap_lock/1){+.+.}-{4:4}, at: mmap_write_lock_nested include/linux/mmap_lock.h:552 [inline]
 #2: ffff8880368f8f80 (&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.0.747/8629: 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_listener_set_doit+0x53d/0x1ab0 fs/nfsd/nfsctl.c:2057
locks held by udevd/9204: 1, on CPU#1:
 #0: ffff888028b87350 (&disk->open_mutex){+.+.}-{4:4}, at: bdev_open+0xde/0xd70 block/bdev.c:990
locks held by syz.2.1198/10257: 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_cache_flush_doit+0xe2/0x1b0 fs/nfsd/nfsctl.c:2319
locks held by syz-executor/10835: 3, last CPU#1:
 #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: ffff88802aebe540 (&mm->mmap_lock){++++}-{4:4}, at: mmap_write_lock_killable include/linux/mmap_lock.h:562 [inline]
 #1: ffff88802aebe540 (&mm->mmap_lock){++++}-{4:4}, at: dup_mmap+0x195/0x1dc0 mm/mmap.c:1716
 #2: ffff88802d47a800 (&mm->mmap_lock/1){+.+.}-{4:4}, at: mmap_write_lock_nested include/linux/mmap_lock.h:552 [inline]
 #2: ffff88802d47a800 (&mm->mmap_lock/1){+.+.}-{4:4}, at: dup_mmap+0x221/0x1dc0 mm/mmap.c:1723
locks held by syz.4.2488/15304: 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: psi_task_switch+0x57/0x7d0 kernel/sched/psi.c:933
locks held by syz-executor/15305: 4, last CPU#1:
 #0: ffff888074549588 (vm_lock){++++}-{0:0}, at: lock_vma_under_rcu+0x1d1/0x500 mm/mmap_lock.c:310
 #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: do_fault_around mm/memory.c:5957 [inline]
 #1: ffffffff8fd5c8a0 (rcu_read_lock){....}-{1:3}, at: do_read_fault mm/memory.c:5991 [inline]
 #1: ffffffff8fd5c8a0 (rcu_read_lock){....}-{1:3}, at: do_fault mm/memory.c:6134 [inline]
 #1: ffffffff8fd5c8a0 (rcu_read_lock){....}-{1:3}, at: do_pte_missing+0x140c/0x34b0 mm/memory.c:4700
 #2: ffffffff8fd5c8a0 (rcu_read_lock){....}-{1:3}, at: rcu_lock_acquire include/linux/rcupdate.h:309 [inline]
 #2: ffffffff8fd5c8a0 (rcu_read_lock){....}-{1:3}, at: rcu_read_lock include/linux/rcupdate.h:849 [inline]
 #2: ffffffff8fd5c8a0 (rcu_read_lock){....}-{1:3}, at: filemap_map_pages+0x1d1/0x2170 mm/filemap.c:3921
 #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

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

NMI backtrace for cpu 1
CPU: 1 UID: 0 PID: 33 Comm: khungtaskd Not tainted syzkaller #0 PREEMPT(full) 
Hardware name: Google Google Compute Engine/Google Compute Engine, BIOS Google 07/24/2026
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 1 to CPUs 0:
NMI backtrace for cpu 0
CPU: 0 UID: 0 PID: 15304 Comm: syz.4.2488 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:arch_local_irq_save arch/x86/include/asm/irqflags.h:127 [inline]
RIP: 0010:lock_acquire+0xb7/0x350 kernel/locking/lockdep.c:5938
Code: a7 ee f2 12 85 c0 0f 85 d5 00 00 00 65 48 8b 2d e7 a9 f2 12 83 bd a4 0b 00 00 00 0f 85 c0 00 00 00 48 89 5c 24 08 4c 89 fb 9c <41> 5f fa 48 c7 c7 32 3b 48 8e e8 ea 4d 45 0a 65 ff 05 6b ee f2 12
RSP: 0018:ffffc90000007e38 EFLAGS: 00000046
RAX: 0000000000000000 RBX: 0000000000000001 RCX: 8000000000000102
RDX: 0000000000000000 RSI: ffffffff8beb4dc0 RDI: 1ffff11017085053
RBP: ffff888027be5dc0 R08: 0000000000000001 R09: 0000000000000000
R10: dffffc0000000000 R11: fffffbfff22f4e30 R12: ffff8880b8428298
R13: 0000000000000000 R14: 0000000000000000 R15: 0000000000000001
FS:  00007faa231536c0(0000) GS:ffff888123abf000(0000) knlGS:0000000000000000
CS:  0010 DS: 0000 ES: 0000 CR0: 0000000080050033
CR2: 000000110c3df849 CR3: 000000007bd2e000 CR4: 00000000003526f0
Call Trace:
 <IRQ>
 __raw_spin_lock_irqsave include/linux/spinlock_api_smp.h:155 [inline]
 _raw_spin_lock_irqsave+0x40/0x60 kernel/locking/spinlock.c:181
 hrtimer_run_softirq+0x71/0x2e0 kernel/time/hrtimer.c:2145
 handle_softirqs+0x226/0x860 kernel/softirq.c:645
 __do_softirq kernel/softirq.c:679 [inline]
 invoke_softirq kernel/softirq.c:519 [inline]
 __irq_exit_rcu+0xcb/0x220 kernel/softirq.c:758
 irq_exit_rcu+0x9/0x30 kernel/softirq.c:775
 instr_sysvec_apic_timer_interrupt arch/x86/kernel/apic/apic.c:1062 [inline]
 sysvec_apic_timer_interrupt+0xa6/0xc0 arch/x86/kernel/apic/apic.c:1062
 </IRQ>
 <TASK>
 asm_sysvec_apic_timer_interrupt+0x1a/0x20 arch/x86/include/asm/idtentry.h:674
RIP: 0010:sk_init_common+0x3de/0xc60 net/core/sock.c:2460
Code: 89 fe e8 65 68 1d f8 41 83 ff 2e 0f 87 11 05 00 00 e8 16 64 1d f8 4e 8d 24 fd 60 a6 22 8d 4c 89 e0 48 c1 e8 03 42 80 3c 28 00 <74> 08 4c 89 e7 e8 38 44 8e f8 49 8b 34 24 41 c1 e7 04 48 8d bb e1
RSP: 0018:ffffc9000409fcf0 EFLAGS: 00000246
RAX: 1ffffffff1a454dc RBX: ffff88802b4f5000 RCX: 0000000000080000
RDX: ffffc90005d6a000 RSI: 00000000000000be RDI: 00000000000000bf
RBP: 0000000000000003 R08: 0000000000000003 R09: 0000000000000000
R10: dffffc0000000000 R11: ffffed100569ea55 R12: ffffffff8d22a6e0
R13: dffffc0000000000 R14: 1ffff1100569ea02 R15: 0000000000000010
 sock_init_data_uid+0x2d/0x980 net/core/sock.c:3755
 __netlink_create+0x7e/0x260 net/netlink/af_netlink.c:631
 netlink_create+0x3ca/0x590 net/netlink/af_netlink.c:685
 __sock_create+0x4b3/0x9d0 net/socket.c:1676
 sock_create net/socket.c:1734 [inline]
 __sys_socket_create net/socket.c:1771 [inline]
 __sys_socket+0xd6/0x1b0 net/socket.c:1818
 __do_sys_socket net/socket.c:1832 [inline]
 __se_sys_socket net/socket.c:1830 [inline]
 __x64_sys_socket+0x7a/0x90 net/socket.c:1830
 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: 0033:0x7faa2219e1d9
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:00007faa23153028 EFLAGS: 00000246 ORIG_RAX: 0000000000000029
RAX: ffffffffffffffda RBX: 00007faa22425fa0 RCX: 00007faa2219e1d9
RDX: 0000000000000000 RSI: 0000000000000003 RDI: 0000000000000010
RBP: 00007faa22235888 R08: 0000000000000000 R09: 0000000000000000
R10: 0000000000000000 R11: 0000000000000246 R12: 0000000000000000
R13: 00007faa22426038 R14: 00007faa22425fa0 R15: 00007ffc9a8dbfe8
 </TASK>