------------[ cut here ]------------
WARNING: CPU: 1 PID: 5260 at mm/rmap.c:444 unlink_anon_vmas+0x63c/0x670
Modules linked in:
CPU: 1 UID: 0 PID: 5260 Comm: mount Not tainted syzkaller #0 PREEMPT(full) 
Hardware name: QEMU Standard PC (Q35 + ICH9, 2009), BIOS 1.16.2-debian-1.16.2-1 04/01/2014
RIP: 0010:unlink_anon_vmas+0x63c/0x670
Code: 08 00 48 3b 6c 24 08 74 29 e8 30 7e af ff 49 89 ee e9 d0 fd ff ff e8 23 7e af ff 90 0f 0b 90 e9 4e fe ff ff e8 15 7e af ff 90 <0f> 0b 90 e9 82 fe ff ff e8 07 7e af ff eb 05 e8 00 7e af ff 48 83
RSP: 0018:ffffc90001bef878 EFLAGS: 00010293
RAX: ffffffff82102ffb RBX: ffff888109476118 RCX: ffff8880215d9cc0
RDX: 0000000000000000 RSI: ffffffffffffffff RDI: 0000000000000000
RBP: ffff88810f31e030 R08: ffff88810947611f R09: 1ffff1102128ec23
R10: dffffc0000000000 R11: ffffed102128ec24 R12: ffffffffffffffff
R13: 1ffff110212a6ce2 R14: ffff888109536710 R15: ffff888109476110
FS:  0000000000000000(0000) GS:ffff8881a3c18000(0000) knlGS:0000000000000000
CS:  0010 DS: 0000 ES: 0000 CR0: 0000000080050033
CR2: 00007f8adf7b0440 CR3: 000000000df36000 CR4: 00000000000006f0
Call Trace:
 <TASK>
 free_pgtables+0x72b/0x9c0
 exit_mmap+0x444/0xb50
 __mmput+0x118/0x420
 exit_mm+0x1da/0x2c0
 do_exit+0x648/0x2300
 do_group_exit+0x21c/0x2d0
 __x64_sys_exit_group+0x3f/0x40
 x64_sys_call+0x21f7/0x2200
 do_syscall_64+0xfa/0x3b0
 entry_SYSCALL_64_after_hwframe+0x77/0x7f
RIP: 0033:0x7f8adf86ea90
Code: Unable to access opcode bytes at 0x7f8adf86ea66.
RSP: 002b:00007fffb8de8148 EFLAGS: 00000246 ORIG_RAX: 00000000000000e7
RAX: ffffffffffffffda RBX: 00007f8adf95f860 RCX: 00007f8adf86ea90
RDX: 00000000000000e7 RSI: 000000000000003c RDI: 0000000000000000
RBP: 00007f8adf95f860 R08: 00007fffb8de7fc0 R09: 00007fffb8de80a0
R10: 00007fffb8de8000 R11: 0000000000000246 R12: 0000000000000000
R13: 0000000000000000 R14: 00007f8adf963658 R15: 0000000000000001
 </TASK>