------------[ cut here ]------------
anon_vma->num_active_vmas
WARNING: mm/rmap.c:528 at unlink_anon_vmas+0x6c5/0x730 mm/rmap.c:528, CPU#0: syz.2.378/7550
Modules linked in:
CPU: 0 UID: 0 PID: 7550 Comm: syz.2.378 Not tainted syzkaller #0 PREEMPT(full) 
Hardware name: Google Google Compute Engine/Google Compute Engine, BIOS Google 01/13/2026
RIP: 0010:unlink_anon_vmas+0x6c5/0x730 mm/rmap.c:528
Code: 08 00 48 3b 6c 24 18 74 29 e8 e7 13 ab ff 49 89 ee e9 cf fd ff ff e8 da 13 ab ff 90 0f 0b 90 e9 4d fe ff ff e8 cc 13 ab ff 90 <0f> 0b 90 e9 81 fe ff ff e8 be 13 ab ff eb 05 e8 b7 13 ab ff 48 83
RSP: 0018:ffffc90003e3f648 EFLAGS: 00010293
RAX: ffffffff82199644 RBX: ffff888077220440 RCX: ffff888031299e40
RDX: 0000000000000000 RSI: ffffffffffffffff RDI: 0000000000000000
RBP: ffff88807c5147b0 R08: ffff88807722044f R09: 1ffff1100ee44089
R10: dffffc0000000000 R11: ffffed100ee4408a R12: ffffffffffffffff
R13: 1ffff1100425651a R14: ffff8880212b28d0 R15: ffff888077220440
FS:  0000000000000000(0000) GS:ffff8881252be000(0000) knlGS:0000000000000000
CS:  0010 DS: 0000 ES: 0000 CR0: 0000000080050033
CR2: 00007fb9bda56000 CR3: 000000001e306000 CR4: 00000000003526f0
Call Trace:
 <TASK>
 free_pgtables+0x842/0xba0 mm/memory.c:429
 exit_mmap+0x482/0x9c0 mm/mmap.c:1313
 __mmput+0x118/0x430 kernel/fork.c:1174
 exit_mm+0x168/0x220 kernel/exit.c:581
 do_exit+0x62e/0x2310 kernel/exit.c:959
 do_group_exit+0x21b/0x2d0 kernel/exit.c:1112
 get_signal+0x1284/0x1330 kernel/signal.c:3034
 arch_do_signal_or_restart+0xbc/0x830 arch/x86/kernel/signal.c:337
 __exit_to_user_mode_loop kernel/entry/common.c:64 [inline]
 exit_to_user_mode_loop+0x86/0x480 kernel/entry/common.c:98
 __exit_to_user_mode_prepare include/linux/irq-entry-common.h:226 [inline]
 syscall_exit_to_user_mode_prepare include/linux/irq-entry-common.h:256 [inline]
 syscall_exit_to_user_mode_work include/linux/entry-common.h:159 [inline]
 syscall_exit_to_user_mode include/linux/entry-common.h:194 [inline]
 do_syscall_64+0x2b7/0xf80 arch/x86/entry/syscall_64.c:100
 entry_SYSCALL_64_after_hwframe+0x77/0x7f
RIP: 0033:0x7f3144b9aeb9
Code: Unable to access opcode bytes at 0x7f3144b9ae8f.
RSP: 002b:00007f3145aed0e8 EFLAGS: 00000246 ORIG_RAX: 00000000000000ca
RAX: fffffffffffffe00 RBX: 00007f3144e15fa8 RCX: 00007f3144b9aeb9
RDX: 0000000000000000 RSI: 0000000000000080 RDI: 00007f3144e15fa8
RBP: 00007f3144e15fa0 R08: 0000000000000000 R09: 0000000000000000
R10: 0000000000000000 R11: 0000000000000246 R12: 0000000000000000
R13: 00007f3144e16038 R14: 00007ffc2c1ce7e0 R15: 00007ffc2c1ce8c8
 </TASK>