INFO: task syz.0.20577:16308 blocked for more than 143 seconds.
      Not tainted syzkaller #0
"echo 0 > /proc/sys/kernel/hung_task_timeout_secs" disables this message.
task:syz.0.20577     state:D stack:25208 pid:16308 tgid:16307 ppid:6839   task_flags:0x400140 flags:0x00080002
Call Trace:
 <TASK>
 context_switch kernel/sched/core.c:5504 [inline]
 __schedule+0x17d9/0x56c0 kernel/sched/core.c:7228
 __schedule_loop kernel/sched/core.c:7307 [inline]
 schedule+0x164/0x360 kernel/sched/core.c:7322
 schedule_preempt_disabled+0x13/0x30 kernel/sched/core.c:7379
 __mutex_lock_common kernel/locking/mutex.c:726 [inline]
 __mutex_lock+0x7bf/0x1550 kernel/locking/mutex.c:821
 nfsd_nl_version_get_doit+0x17c/0xd20 fs/nfsd/nfsctl.c:1873
 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:2556
 genl_rcv+0x28/0x40 net/netlink/genetlink.c:1218
 netlink_unicast_kernel net/netlink/af_netlink.c:1319 [inline]
 netlink_unicast+0x7bb/0x940 net/netlink/af_netlink.c:1345
 netlink_sendmsg+0x813/0xb40 net/netlink/af_netlink.c:1900
 sock_sendmsg_nosec net/socket.c:775 [inline]
 __sock_sendmsg net/socket.c:790 [inline]
 ____sys_sendmsg+0x9b9/0xa20 net/socket.c:2684
 ___sys_sendmsg+0x2a5/0x360 net/socket.c:2738
 __sys_sendmsg net/socket.c:2770 [inline]
 __do_sys_sendmsg net/socket.c:2775 [inline]
 __se_sys_sendmsg net/socket.c:2773 [inline]
 __x64_sys_sendmsg+0x1b1/0x290 net/socket.c:2773
 do_syscall_x64 arch/x86/entry/syscall_64.c:63 [inline]
 do_syscall_64+0x174/0x580 arch/x86/entry/syscall_64.c:94
 entry_SYSCALL_64_after_hwframe+0x77/0x7f
RIP: 0033:0x7fc22079ce59
RSP: 002b:00007fc2215a0028 EFLAGS: 00000246 ORIG_RAX: 000000000000002e
RAX: ffffffffffffffda RBX: 00007fc220a15fa0 RCX: 00007fc22079ce59
RDX: 0000000020048000 RSI: 0000200000000000 RDI: 0000000000000008
RBP: 00007fc220832e6f R08: 0000000000000000 R09: 0000000000000000
R10: 0000000000000000 R11: 0000000000000246 R12: 0000000000000000
R13: 00007fc220a16038 R14: 00007fc220a15fa0 R15: 00007ffd2ebbf978
 </TASK>
INFO: lockdep is turned off.
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 05/09/2026
Call Trace:
 <TASK>
 dump_stack_lvl+0xe8/0x150 lib/dump_stack.c:120
 nmi_cpu_backtrace+0x274/0x2d0 lib/nmi_backtrace.c:113
 nmi_trigger_cpumask_backtrace+0x17a/0x300 lib/nmi_backtrace.c:62
 trigger_all_cpu_backtrace include/linux/nmi.h:162 [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+0x388/0x470 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: 23434 Comm: syz.5.22480 Not tainted syzkaller #0 PREEMPT(full) 
Hardware name: Google Google Compute Engine/Google Compute Engine, BIOS Google 05/09/2026
RIP: 0010:orc_find arch/x86/kernel/unwind_orc.c:228 [inline]
RIP: 0010:unwind_next_frame+0x1f1/0x2550 arch/x86/kernel/unwind_orc.c:510
Code: 29 c7 49 c1 ef 08 8b 15 dd 29 b1 0c 8d 42 ff 44 39 f8 0f 86 6c 04 00 00 44 89 f8 4c 8d 2c 85 3c a5 71 91 4c 89 e8 48 c1 e8 03 <42> 0f b6 04 20 84 c0 4c 89 e3 0f 85 66 1d 00 00 45 8b 6d 00 44 89
RSP: 0018:ffffc90007baf128 EFLAGS: 00000a06
RAX: 1ffffffff22e6b3f RBX: 0000000000000001 RCX: 0000000080000000
RDX: 00000000000aabc9 RSI: ffffffff8c291100 RDI: ffffffff8c2910c0
RBP: ffffffff816d2f12 R08: 0000000000000000 R09: 0000000000000000
R10: ffffc90007baf278 R11: fffff52000f75e51 R12: dffffc0000000000
R13: ffffffff917359f8 R14: ffffc90007baf228 R15: 0000000000006d2f
FS:  0000000000000000(0000) GS:ffff88812527b000(0000) knlGS:0000000000000000
CS:  0010 DS: 0000 ES: 0000 CR0: 0000000080050033
CR2: 0000000000000000 CR3: 000000003652e000 CR4: 00000000003526f0
Call Trace:
 <TASK>
 __unwind_start+0x514/0x660 arch/x86/kernel/unwind_orc.c:787
 unwind_start arch/x86/include/asm/unwind.h:64 [inline]
 arch_stack_walk+0xe3/0x150 arch/x86/kernel/stacktrace.c:24
 stack_trace_save+0xa9/0x100 kernel/stacktrace.c:122
 kasan_save_stack+0x3e/0x60 mm/kasan/common.c:57
 kasan_record_aux_stack+0xbd/0xd0 mm/kasan/generic.c:556
 slab_free_hook mm/slub.c:2661 [inline]
 slab_free mm/slub.c:6310 [inline]
 kmem_cache_free+0x44f/0x650 mm/slub.c:6437
 anon_vma_free mm/rmap.c:137 [inline]
 __put_anon_vma+0x12b/0x2d0 mm/rmap.c:2917
 put_anon_vma mm/internal.h:216 [inline]
 unlink_anon_vmas+0x589/0x730 mm/rmap.c:536
 free_pgtables+0x836/0xb70 mm/memory.c:414
 exit_mmap+0x4aa/0x9f0 mm/mmap.c:1312
 __mmput+0x118/0x420 kernel/fork.c:1181
 exit_mm+0x221/0x2d0 kernel/exit.c:610
 do_exit+0x6cd/0x2360 kernel/exit.c:992
 do_group_exit+0x22d/0x2f0 kernel/exit.c:1147
 get_signal+0x121b/0x12c0 kernel/signal.c:3038
 arch_do_signal_or_restart+0xbb/0x860 arch/x86/kernel/signal.c:337
 __exit_to_user_mode_loop kernel/entry/common.c:66 [inline]
 exit_to_user_mode_loop+0x104/0x730 kernel/entry/common.c:101
 __exit_to_user_mode_prepare include/linux/irq-entry-common.h:207 [inline]
 syscall_exit_to_user_mode_prepare include/linux/irq-entry-common.h:230 [inline]
 syscall_exit_to_user_mode include/linux/entry-common.h:318 [inline]
 do_syscall_64+0x353/0x580 arch/x86/entry/syscall_64.c:100
 entry_SYSCALL_64_after_hwframe+0x77/0x7f
RIP: 0033:0x7f5b4379ce59
Code: Unable to access opcode bytes at 0x7f5b4379ce2f.
RSP: 002b:00007f5b44729028 EFLAGS: 00000246 ORIG_RAX: 0000000000000010
RAX: fffffffffffffff2 RBX: 00007f5b43a15fa0 RCX: 00007f5b4379ce59
RDX: 0000200000001000 RSI: 00000000000089f8 RDI: 0000000000000003
RBP: 00007f5b43832e6f R08: 0000000000000000 R09: 0000000000000000
R10: 0000000000000000 R11: 0000000000000246 R12: 0000000000000000
R13: 00007f5b43a16038 R14: 00007f5b43a15fa0 R15: 00007ffd420a1858
 </TASK>