kernel BUG at mm/memory.c:LINE!

[syzbot]

Hello,

syzbot found the following crash on:

HEAD commit:    b2d44d145d2a Merge tag '4.18-rc3-smb3fixes' of git://git.s..
git tree:       upstream
console output: https://syzkaller.appspot.com/x/log.txt?x=11d07748400000
kernel config:  https://syzkaller.appspot.com/x/.config?x=2ca6c7a31d407f86
dashboard link: https://syzkaller.appspot.com/bug?extid=3f84280d52be9b7083cc
compiler:       gcc (GCC) 8.0.1 20180413 (experimental)

Unfortunately, I don't have any reproducer for this crash yet.

IMPORTANT: if you fix the bug, please add the following tag to the commit:
Reported-by: syzbot+3f84280d52be9b7083cc@xxxxxxxxxxxxxxxxxxxxxxxxx

next ffff8801ce5e7040 prev ffff8801d20eca50 mm ffff88019c1e13c0
prot 27 anon_vma ffff88019680cdd8 vm_ops 0000000000000000
pgoff 0 file ffff8801b2ec2d00 private_data 0000000000000000
flags: 0xff(read|write|exec|shared|mayread|maywrite|mayexec|mayshare)
------------[ cut here ]------------
kernel BUG at mm/memory.c:1422!
invalid opcode: 0000 [#1] SMP KASAN
CPU: 0 PID: 18486 Comm: syz-executor3 Not tainted 4.18.0-rc3+ #136
Hardware name: Google Google Compute Engine/Google Compute Engine, BIOS  
Google 01/01/2011
RIP: 0010:zap_pmd_range mm/memory.c:1421 [inline]
RIP: 0010:zap_pud_range mm/memory.c:1466 [inline]
RIP: 0010:zap_p4d_range mm/memory.c:1487 [inline]
RIP: 0010:unmap_page_range+0x1c18/0x2220 mm/memory.c:1508
Code: ff 31 ff 4c 89 e6 42 c6 04 33 f8 e8 92 dd d0 ff 4d 85 e4 0f 85 4a eb  
ff ff e8 54 dc d0 ff 48 8b bd 10 fc ff ff e8 82 95 fe ff <0f> 0b e8 41 dc  
d0 ff 0f 0b 4c 89 ad 18 fc ff ff c7 85 7c fb ff ff
RSP: 0018:ffff8801b0587330 EFLAGS: 00010286
RAX: 000000000000013c RBX: 1ffff100360b0e9c RCX: ffffc90002620000
RDX: 0000000000000000 RSI: ffffffff81631851 RDI: 0000000000000001
RBP: ffff8801b05877c8 R08: ffff880199d40300 R09: ffffed003b5c4fc0
R10: ffffed003b5c4fc0 R11: ffff8801dae27e07 R12: 0000000000000000
R13: ffff88019c1e13c0 R14: dffffc0000000000 R15: 0000000020e01000
FS:  00007fca32251700(0000) GS:ffff8801dae00000(0000) knlGS:0000000000000000
CS:  0010 DS: 0000 ES: 0000 CR0: 0000000080050033
CR2: 00007f04c540d000 CR3: 00000001ac1f0000 CR4: 00000000001426f0
DR0: 0000000000000000 DR1: 0000000000000000 DR2: 0000000000000000
DR3: 0000000000000000 DR6: 00000000fffe0ff0 DR7: 0000000000000400
Call Trace:
 unmap_single_vma+0x1a0/0x310 mm/memory.c:1553
 zap_page_range_single+0x3cc/0x580 mm/memory.c:1644
 unmap_mapping_range_vma mm/memory.c:2792 [inline]
 unmap_mapping_range_tree mm/memory.c:2813 [inline]
 unmap_mapping_pages+0x3a7/0x5b0 mm/memory.c:2845
 unmap_mapping_range+0x48/0x60 mm/memory.c:2880
 truncate_pagecache+0x54/0x90 mm/truncate.c:800
 truncate_setsize+0x70/0xb0 mm/truncate.c:826
 simple_setattr+0xe9/0x110 fs/libfs.c:409
 notify_change+0xf13/0x10f0 fs/attr.c:335
 do_truncate+0x1ac/0x2b0 fs/open.c:63
 do_sys_ftruncate+0x492/0x560 fs/open.c:205
 __do_sys_ftruncate fs/open.c:215 [inline]
 __se_sys_ftruncate fs/open.c:213 [inline]
 __x64_sys_ftruncate+0x59/0x80 fs/open.c:213
 do_syscall_64+0x1b9/0x820 arch/x86/entry/common.c:290
 entry_SYSCALL_64_after_hwframe+0x49/0xbe
RIP: 0033:0x455ba9
Code: 1d ba fb ff c3 66 2e 0f 1f 84 00 00 00 00 00 66 90 48 89 f8 48 89 f7  
48 89 d6 48 89 ca 4d 89 c2 4d 89 c8 4c 8b 4c 24 08 0f 05 <48> 3d 01 f0 ff  
ff 0f 83 eb b9 fb ff c3 66 2e 0f 1f 84 00 00 00 00
RSP: 002b:00007fca32250c68 EFLAGS: 00000246 ORIG_RAX: 000000000000004d
RAX: ffffffffffffffda RBX: 00007fca322516d4 RCX: 0000000000455ba9
RDX: 0000000000000000 RSI: 0000000000000006 RDI: 0000000000000010
RBP: 000000000072bea0 R08: 0000000000000000 R09: 0000000000000000
R10: 0000000000000000 R11: 0000000000000246 R12: 00000000ffffffff
R13: 00000000004bbd22 R14: 00000000004c90e8 R15: 0000000000000000
Modules linked in:
Dumping ftrace buffer:
   (ftrace buffer empty)
---[ end trace a92a1c818e9b1620 ]---
RIP: 0010:zap_pmd_range mm/memory.c:1421 [inline]
RIP: 0010:zap_pud_range mm/memory.c:1466 [inline]
RIP: 0010:zap_p4d_range mm/memory.c:1487 [inline]
RIP: 0010:unmap_page_range+0x1c18/0x2220 mm/memory.c:1508
Code: ff 31 ff 4c 89 e6 42 c6 04 33 f8 e8 92 dd d0 ff 4d 85 e4 0f 85 4a eb  
ff ff e8 54 dc d0 ff 48 8b bd 10 fc ff ff e8 82 95 fe ff <0f> 0b e8 41 dc  
d0 ff 0f 0b 4c 89 ad 18 fc ff ff c7 85 7c fb ff ff
RSP: 0018:ffff8801b0587330 EFLAGS: 00010286
RAX: 000000000000013c RBX: 1ffff100360b0e9c RCX: ffffc90002620000
RDX: 0000000000000000 RSI: ffffffff81631851 RDI: 0000000000000001
RBP: ffff8801b05877c8 R08: ffff880199d40300 R09: ffffed003b5c4fc0
R10: ffffed003b5c4fc0 R11: ffff8801dae27e07 R12: 0000000000000000
R13: ffff88019c1e13c0 R14: dffffc0000000000 R15: 0000000020e01000
FS:  00007fca32251700(0000) GS:ffff8801dae00000(0000) knlGS:0000000000000000
CS:  0010 DS: 0000 ES: 0000 CR0: 0000000080050033
CR2: 00007f04c540d000 CR3: 00000001ac1f0000 CR4: 00000000001426f0
DR0: 0000000000000000 DR1: 0000000000000000 DR2: 0000000000000000
DR3: 0000000000000000 DR6: 00000000fffe0ff0 DR7: 0000000000000400


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