BUG: kernel NULL pointer dereference, address: 0000000000000000
#PF: supervisor read access in kernel mode
#PF: error_code(0x0000) - not-present page
PGD 954c0067 P4D 954c0067 PUD 95ce5067 PMD 0 
Oops: 0000 [#1] PREEMPT SMP KASAN
CPU: 0 PID: 10875 Comm: syz-executor.4 Not tainted 5.7.0-syzkaller #0
Hardware name: Google Google Compute Engine/Google Compute Engine, BIOS Google 01/01/2011
RIP: 0010:__read_once_size include/linux/compiler.h:252 [inline]
RIP: 0010:__sanitizer_cov_trace_pc+0x3f/0x60 kernel/kcov.c:202
Code: c2 00 01 ff 00 74 11 f7 c2 00 01 00 00 74 35 83 b9 04 14 00 00 00 74 2c 8b 91 e0 13 00 00 83 fa 02 75 21 48 8b 91 e8 13 00 00 <48> 8b 32 48 8d 7e 01 8b 89 e4 13 00 00 48 39 cf 73 08 48 89 44 f2
RSP: 0018:ffffc900019378e8 EFLAGS: 00010246
RAX: ffffffff81a4ee0c RBX: 0000000000000000 RCX: ffff8880a6bb2340
RDX: 0000000000000000 RSI: 0000000000000000 RDI: 0000000000000000
RBP: ffffc90001937a28 R08: ffffffff81a4edf8 R09: fffff9400033fe81
R10: fffff9400033fe81 R11: 0000000000000000 R12: 00007f4dfba82000
R13: dffffc0000000000 R14: ffff8880657b7408 R15: ffffea00019ff400
FS:  00007f4dfa1c0700(0000) GS:ffff8880ae800000(0000) knlGS:0000000000000000
CS:  0010 DS: 0000 ES: 0000 CR0: 0000000080050033
CR2: 0000000000000000 CR3: 0000000095e83000 CR4: 00000000001406f0
DR0: 0000000000000000 DR1: 0000000000000000 DR2: 0000000000000000
DR3: 0000000000000000 DR6: 00000000fffe0ff0 DR7: 0000000000000400
Call Trace:
 page_mapcount include/linux/mm.h:817 [inline]
 zap_pte_range+0xadc/0x1d90 mm/memory.c:1091
 zap_pmd_range mm/memory.c:1194 [inline]
 zap_pud_range mm/memory.c:1223 [inline]
 zap_p4d_range mm/memory.c:1244 [inline]
 unmap_page_range+0x9a0/0xb00 mm/memory.c:1265
 unmap_vmas+0x15d/0x2c0 mm/memory.c:1342
 exit_mmap+0x276/0x530 mm/mmap.c:3150
 __mmput+0x113/0x350 kernel/fork.c:1094
 mmput kernel/fork.c:1115 [inline]
 copy_process+0x41fd/0x52f0 kernel/fork.c:2338
 _do_fork+0x134/0x650 kernel/fork.c:2444
 __do_sys_clone kernel/fork.c:2600 [inline]
 __se_sys_clone kernel/fork.c:2581 [inline]
 __x64_sys_clone+0x21c/0x260 kernel/fork.c:2581
 do_syscall_64+0xf3/0x1b0 arch/x86/entry/common.c:295
 entry_SYSCALL_64_after_hwframe+0x49/0xb3
RIP: 0033:0x45ca59
Code: 0d b7 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 db b6 fb ff c3 66 2e 0f 1f 84 00 00 00 00
RSP: 002b:00007f4dfa1bfc78 EFLAGS: 00000246 ORIG_RAX: 0000000000000038
RAX: ffffffffffffffda RBX: 00000000004db0a0 RCX: 000000000045ca59
RDX: 9999999999999999 RSI: 0000000000000000 RDI: 000000001b242000
RBP: 000000000078bf00 R08: ffffffffffffffff R09: 0000000000000000
R10: 0000000000000000 R11: 0000000000000246 R12: 00000000ffffffff
R13: 000000000000007b R14: 00000000004c33b4 R15: 00007f4dfa1c06d4
Modules linked in:
CR2: 0000000000000000
---[ end trace 89683489b0e8196b ]---
RIP: 0010:__read_once_size include/linux/compiler.h:252 [inline]
RIP: 0010:__sanitizer_cov_trace_pc+0x3f/0x60 kernel/kcov.c:202
Code: c2 00 01 ff 00 74 11 f7 c2 00 01 00 00 74 35 83 b9 04 14 00 00 00 74 2c 8b 91 e0 13 00 00 83 fa 02 75 21 48 8b 91 e8 13 00 00 <48> 8b 32 48 8d 7e 01 8b 89 e4 13 00 00 48 39 cf 73 08 48 89 44 f2
RSP: 0018:ffffc900019378e8 EFLAGS: 00010246
RAX: ffffffff81a4ee0c RBX: 0000000000000000 RCX: ffff8880a6bb2340
RDX: 0000000000000000 RSI: 0000000000000000 RDI: 0000000000000000
RBP: ffffc90001937a28 R08: ffffffff81a4edf8 R09: fffff9400033fe81
R10: fffff9400033fe81 R11: 0000000000000000 R12: 00007f4dfba82000
R13: dffffc0000000000 R14: ffff8880657b7408 R15: ffffea00019ff400
FS:  00007f4dfa1c0700(0000) GS:ffff8880ae800000(0000) knlGS:0000000000000000
CS:  0010 DS: 0000 ES: 0000 CR0: 0000000080050033
CR2: 0000000000000000 CR3: 0000000095e83000 CR4: 00000000001406f0
DR0: 0000000000000000 DR1: 0000000000000000 DR2: 0000000000000000
DR3: 0000000000000000 DR6: 00000000fffe0ff0 DR7: 0000000000000400