BUG: unable to handle kernel NULL pointer dereference at 0000000000000007
PGD 800000013b5ff067 P4D 800000013b5ff067 PUD 13b602067 PMD 0 
Oops: 0000 [#1] SMP PTI
CPU: 0 PID: 5552 Comm: syz-executor4 Not tainted 4.18.0-rc5+ #28
Hardware name: Google Google Compute Engine/Google Compute Engine, BIOS Google 01/01/2011
RIP: 0010:tlb_flush_mmu_free mm/memory.c:259 [inline]
RIP: 0010:zap_pte_range mm/memory.c:1401 [inline]
RIP: 0010:zap_pmd_range mm/memory.c:1438 [inline]
RIP: 0010:zap_pud_range mm/memory.c:1467 [inline]
RIP: 0010:zap_p4d_range mm/memory.c:1488 [inline]
RIP: 0010:unmap_page_range+0x31c6/0x3c00 mm/memory.c:1509
Code: 8b a4 24 98 01 00 00 eb 13 90 66 2e 0f 1f 84 00 00 00 00 00 e8 5b 0e bb ff 49 89 dc 4d 8d 7c 24 08 4d 85 f6 0f 85 bd 00 00 00 <41> 8b 1f 4c 89 ff e8 9f b8 16 00 44 8b 28 8b 12 45 85 ed 74 0d 44 
RSP: 0018:ffff8800a0a8f210 EFLAGS: 00010246
RAX: ffffffff81ad16a5 RBX: ffffffffffffffff RCX: ffff880193018000
RDX: 0000000000000000 RSI: 0000000000000000 RDI: ffffea00041f5800
RBP: ffff8800a0a8f470 R08: 0000000000480020 R09: 0000000000000002
R10: 0000000000000000 R11: 0000000000000000 R12: ffffffffffffffff
R13: 0000000000000000 R14: 0000000000000000 R15: 0000000000000007
FS:  00007ffa1f25e700(0000) GS:ffff88021fc00000(0000) knlGS:0000000000000000
CS:  0010 DS: 0000 ES: 0000 CR0: 0000000080050033
CR2: 0000000000000007 CR3: 000000013b0b8000 CR4: 00000000001406f0
DR0: 0000000020000000 DR1: 0000000020000000 DR2: 0000000000000000
DR3: 0000000000000000 DR6: 00000000fffe0ff0 DR7: 0000000000000600
Call Trace:
 unmap_single_vma+0x445/0x5e0 mm/memory.c:1554
 unmap_vmas+0x1f4/0x360 mm/memory.c:1584
 exit_mmap+0x570/0xad0 mm/mmap.c:3100
 __mmput+0x165/0x620 kernel/fork.c:971
 mmput+0xbb/0x110 kernel/fork.c:992
 exit_mm+0x6bb/0x7c0 kernel/exit.c:545
 do_exit+0xc12/0x3930 kernel/exit.c:854
 do_group_exit+0x1a0/0x360 kernel/exit.c:970
 get_signal+0x15c3/0x2190 kernel/signal.c:2468
 do_signal+0xca/0x2060 arch/x86/kernel/signal.c:816
 exit_to_usermode_loop arch/x86/entry/common.c:162 [inline]
 prepare_exit_to_usermode+0x297/0x430 arch/x86/entry/common.c:197
 syscall_return_slowpath+0x108/0x800 arch/x86/entry/common.c:268
 do_syscall_64+0x1ad/0x230 arch/x86/entry/common.c:293
 entry_SYSCALL_64_after_hwframe+0x63/0xe7
RIP: 0033:0x455ab9
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:00007ffa1f25dce8 EFLAGS: 00000246 ORIG_RAX: 00000000000000ca
RAX: 0000000000000000 RBX: 000000000072bec0 RCX: 0000000000455ab9
RDX: 0000000000000000 RSI: 0000000000000000 RDI: 000000000072bec0
RBP: 000000000072bec0 R08: 0000000000000000 R09: 000000000072bea0
R10: 0000000000000000 R11: 0000000000000246 R12: 0000000000000000
R13: 0000000000a3e80f R14: 00007ffa1f25e9c0 R15: 0000000000000000
Modules linked in:
Dumping ftrace buffer:
   (ftrace buffer empty)
CR2: 0000000000000007
---[ end trace b9449c53654b2877 ]---
RIP: 0010:tlb_flush_mmu_free mm/memory.c:259 [inline]
RIP: 0010:zap_pte_range mm/memory.c:1401 [inline]
RIP: 0010:zap_pmd_range mm/memory.c:1438 [inline]
RIP: 0010:zap_pud_range mm/memory.c:1467 [inline]
RIP: 0010:zap_p4d_range mm/memory.c:1488 [inline]
RIP: 0010:unmap_page_range+0x31c6/0x3c00 mm/memory.c:1509
Code: 8b a4 24 98 01 00 00 eb 13 90 66 2e 0f 1f 84 00 00 00 00 00 e8 5b 0e bb ff 49 89 dc 4d 8d 7c 24 08 4d 85 f6 0f 85 bd 00 00 00 <41> 8b 1f 4c 89 ff e8 9f b8 16 00 44 8b 28 8b 12 45 85 ed 74 0d 44 
RSP: 0018:ffff8800a0a8f210 EFLAGS: 00010246
RAX: ffffffff81ad16a5 RBX: ffffffffffffffff RCX: ffff880193018000
RDX: 0000000000000000 RSI: 0000000000000000 RDI: ffffea00041f5800
RBP: ffff8800a0a8f470 R08: 0000000000480020 R09: 0000000000000002
R10: 0000000000000000 R11: 0000000000000000 R12: ffffffffffffffff
R13: 0000000000000000 R14: 0000000000000000 R15: 0000000000000007
FS:  00007ffa1f25e700(0000) GS:ffff88021fc00000(0000) knlGS:0000000000000000
CS:  0010 DS: 0000 ES: 0000 CR0: 0000000080050033
CR2: 0000000000000007 CR3: 000000013b0b8000 CR4: 00000000001406f0
DR0: 0000000020000000 DR1: 0000000020000000 DR2: 0000000000000000
DR3: 0000000000000000 DR6: 00000000fffe0ff0 DR7: 0000000000000600