R10: ffffffffffffffff R11: 0000000000000246 R12: 0000000000000001
R13: 00007f4f78c15fac R14: 00007f4f78c15fa0 R15: 00007f4f78c15fa0
 </TASK>
------------[ cut here ]------------
anon_vma->num_active_vmas
WARNING: mm/rmap.c:528 at unlink_anon_vmas+0x646/0x8d0 mm/rmap.c:528, CPU#0: syz.0.17/5912
Modules linked in:
CPU: 0 UID: 0 PID: 5912 Comm: syz.0.17 Not tainted 7.0.0-rc3 #1 PREEMPT(full) 
Hardware name: QEMU Standard PC (i440FX + PIIX, 1996), BIOS 1.17.0-debian-1.17.0-1 04/01/2014
RIP: 0010:unlink_anon_vmas+0x646/0x8d0 mm/rmap.c:528
Code: 8b 40 30 48 39 c3 0f 85 9c 00 00 00 e8 83 26 a8 ff 48 83 c4 28 5b 5d 41 5c 41 5d 41 5e 41 5f e9 9b 89 ae fe e8 6b 26 a8 ff 90 <0f> 0b 90 e9 30 ff ff ff e8 5d 26 a8 ff 90 0f 0b 90 e9 e4 fe ff ff
RSP: 0018:ffa00000022e7998 EFLAGS: 00010293
RAX: 0000000000000000 RBX: ff11000022ae63f0 RCX: ffffffff8261b6a3
RDX: ff1100002497a500 RSI: ffffffff8261b775 RDI: 0000000000000007
RBP: ff1100001dbc2330 R08: ffffffff8261b6a3 R09: ffffffffffffffff
R10: 0000000000000007 R11: 0000000000000000 R12: dffffc0000000000
R13: ff110000262ba020 R14: ff11000022ae6400 R15: ff110000262ba030
FS:  0000000000000000(0000) GS:ff11000096769000(0000) knlGS:0000000000000000
CS:  0010 DS: 0000 ES: 0000 CR0: 0000000080050033
CR2: 0000001b34463fff CR3: 000000000f19a000 CR4: 0000000000751ef0
PKRU: 00000000
Call Trace:
 <TASK>
 free_pgtables+0x2e8/0x900 mm/memory.c:427
 exit_mmap+0x45b/0xa40 mm/mmap.c:1314
 __mmput+0x12a/0x440 kernel/fork.c:1174
 mmput+0x67/0x80 kernel/fork.c:1197
 exit_mm kernel/exit.c:581 [inline]
 do_exit+0x800/0x2b60 kernel/exit.c:964
 do_group_exit+0xd5/0x2a0 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+0x3c/0x50 kernel/exit.c:1127
 x64_sys_call+0x102c/0x1530 arch/x86/include/generated/asm/syscalls_64.h:232
 do_syscall_x64 arch/x86/entry/syscall_64.c:63 [inline]
 do_syscall_64+0xff/0xf80 arch/x86/entry/syscall_64.c:94
 entry_SYSCALL_64_after_hwframe+0x77/0x7f
RIP: 0033:0x7f4f7899c799
Code: Unable to access opcode bytes at 0x7f4f7899c76f.
RSP: 002b:00007ffd17a4c568 EFLAGS: 00000246 ORIG_RAX: 00000000000000e7
RAX: ffffffffffffffda RBX: 0000000000000000 RCX: 00007f4f7899c799
RDX: 0000000000000064 RSI: 0000000000000000 RDI: 0000000000000000
RBP: 0000000000000003 R08: 0000000000000000 R09: 00007f4f78be63e0
R10: 0000000000000001 R11: 0000000000000246 R12: 0000000000000000
R13: 00007f4f78be63e0 R14: 0000000000000003 R15: 00007ffd17a4c620
 </TASK>
