------------[ cut here ]------------
anon_vma->num_active_vmas
WARNING: mm/rmap.c:528 at unlink_anon_vmas+0x6c5/0x730 mm/rmap.c:528, CPU#1: syz.3.1018/9017
Modules linked in:
CPU: 1 UID: 0 PID: 9017 Comm: syz.3.1018 Not tainted syzkaller #0 PREEMPT_{RT,(full)} 
Hardware name: Google Google Compute Engine/Google Compute Engine, BIOS Google 02/12/2026
RIP: 0010:unlink_anon_vmas+0x6c5/0x730 mm/rmap.c:528
Code: 08 00 48 3b 6c 24 18 74 29 e8 07 a5 ad ff 49 89 ee e9 cf fd ff ff e8 fa a4 ad ff 90 0f 0b 90 e9 4d fe ff ff e8 ec a4 ad ff 90 <0f> 0b 90 e9 81 fe ff ff e8 de a4 ad ff eb 05 e8 d7 a4 ad ff 48 83
RSP: 0018:ffffc9001d387888 EFLAGS: 00010293
RAX: ffffffff8216c124 RBX: ffff8880296d2100 RCX: ffff8880628a1e80
RDX: 0000000000000000 RSI: 0000000000000000 RDI: 0000000000000000
RBP: ffff88806b6cd8f0 R08: 0000000000000000 R09: 0000000000000000
R10: dffffc0000000000 R11: fffffbfff1ed4797 R12: ffffffffffffffff
R13: 1ffff110074bb472 R14: ffff88803a5da390 R15: ffff8880296d2100
FS:  0000000000000000(0000) GS:ffff88812643c000(0000) knlGS:0000000000000000
CS:  0010 DS: 0000 ES: 0000 CR0: 0000000080050033
CR2: 0000200000004000 CR3: 000000002935c000 CR4: 00000000003526f0
Call Trace:
 <TASK>
 free_pgtables+0x836/0xb70 mm/memory.c:427
 exit_mmap+0x490/0xa10 mm/mmap.c:1314
 __mmput+0xcb/0x3d0 kernel/fork.c:1174
 exit_mm+0x168/0x220 kernel/exit.c:581
 do_exit+0x6a2/0x23c0 kernel/exit.c:964
 do_group_exit+0x21b/0x2d0 kernel/exit.c:1118
 __do_sys_exit_group kernel/exit.c:1129 [inline]
 __se_sys_exit_group kernel/exit.c:1127 [inline]
 __x64_sys_exit_group+0x3f/0x40 kernel/exit.c:1127
 x64_sys_call+0x221a/0x2240 arch/x86/include/generated/asm/syscalls_64.h:232
 do_syscall_x64 arch/x86/entry/syscall_64.c:63 [inline]
 do_syscall_64+0x14d/0xf80 arch/x86/entry/syscall_64.c:94
 entry_SYSCALL_64_after_hwframe+0x77/0x7f
RIP: 0033:0x7f17b2d6c799
Code: Unable to access opcode bytes at 0x7f17b2d6c76f.
RSP: 002b:00007ffe0a676268 EFLAGS: 00000246 ORIG_RAX: 00000000000000e7
RAX: ffffffffffffffda RBX: 0000000000000000 RCX: 00007f17b2d6c799
RDX: 0000000000000064 RSI: 0000000000000000 RDI: 0000000000000000
RBP: 00007ffe0a6762cc R08: 0000000000000000 R09: 00000000000927c0
R10: 0000000000000001 R11: 0000000000000246 R12: 0000000000000147
R13: 00000000000927c0 R14: 0000000000050ccd R15: 00007ffe0a676320
 </TASK>