BUG: kernel NULL pointer dereference, address: 0000000000000000
#PF: supervisor instruction fetch in kernel mode
#PF: error_code(0x0010) - not-present page
PGD 89c5c067 P4D 89c5c067 PUD 9431a067 PMD 0 
Oops: 0010 [#1] PREEMPT SMP KASAN
CPU: 1 PID: 21337 Comm: syz-executor.1 Not tainted 5.3.0-rc6+ #121
Hardware name: Google Google Compute Engine/Google Compute Engine, BIOS Google 01/01/2011
RIP: 0010:0x0
Code: Bad RIP value.
RSP: 0018:ffff8880a39cf9b0 EFLAGS: 00010246
RAX: ffffffff879c54c0 RBX: 0000000000000000 RCX: 0000000000000028
RDX: 0000000000000000 RSI: ffff8880876744b0 RDI: ffff88808b1c4080
RBP: ffff8880a39cfad0 R08: 0000000000000000 R09: ffff8880a39cfa48
R10: ffffed1009e52070 R11: ffff88804f290387 R12: 0000000000000028
R13: ffff8880a39cfaa8 R14: ffff8880876744b0 R15: ffff8880a39cfcc0
FS:  00007f11d5649700(0000) GS:ffff8880ae900000(0000) knlGS:0000000000000000
CS:  0010 DS: 0000 ES: 0000 CR0: 0000000080050033
CR2: ffffffffffffffd6 CR3: 000000004b960000 CR4: 00000000001426e0
DR0: 0000000000000000 DR1: 0000000000000000 DR2: 0000000000000000
DR3: 0000000000000000 DR6: 00000000fffe0ff0 DR7: 0000000000000400
Call Trace:
 generic_perform_write+0x23b/0x540 mm/filemap.c:3327
 __generic_file_write_iter+0x25e/0x630 mm/filemap.c:3456
 ext4_file_write_iter+0x373/0x1430 fs/ext4/file.c:270
 call_write_iter include/linux/fs.h:1870 [inline]
 new_sync_write+0x4d3/0x770 fs/read_write.c:483
 __vfs_write+0xe1/0x110 fs/read_write.c:496
 vfs_write+0x268/0x5d0 fs/read_write.c:558
 ksys_write+0x14f/0x290 fs/read_write.c:611
 __do_sys_write fs/read_write.c:623 [inline]
 __se_sys_write fs/read_write.c:620 [inline]
 __x64_sys_write+0x73/0xb0 fs/read_write.c:620
 do_syscall_64+0xfd/0x6a0 arch/x86/entry/common.c:296
 entry_SYSCALL_64_after_hwframe+0x49/0xbe
RIP: 0033:0x459879
Code: fd 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 cb b7 fb ff c3 66 2e 0f 1f 84 00 00 00 00
RSP: 002b:00007f11d5648c78 EFLAGS: 00000246 ORIG_RAX: 0000000000000001
RAX: ffffffffffffffda RBX: 0000000000000003 RCX: 0000000000459879
RDX: 0000000000000028 RSI: 00000000200000c0 RDI: 0000000000000003
RBP: 000000000075bf20 R08: 0000000000000000 R09: 0000000000000000
R10: 0000000000000000 R11: 0000000000000246 R12: 00007f11d56496d4
R13: 00000000004c93aa R14: 00000000004e0708 R15: 00000000ffffffff
Modules linked in:
CR2: 0000000000000000
---[ end trace e3d97060b907ff30 ]---
RIP: 0010:0x0
Code: Bad RIP value.
RSP: 0018:ffff8880a39cf9b0 EFLAGS: 00010246
RAX: ffffffff879c54c0 RBX: 0000000000000000 RCX: 0000000000000028
RDX: 0000000000000000 RSI: ffff8880876744b0 RDI: ffff88808b1c4080
RBP: ffff8880a39cfad0 R08: 0000000000000000 R09: ffff8880a39cfa48
R10: ffffed1009e52070 R11: ffff88804f290387 R12: 0000000000000028
R13: ffff8880a39cfaa8 R14: ffff8880876744b0 R15: ffff8880a39cfcc0
FS:  00007f11d5649700(0000) GS:ffff8880ae900000(0000) knlGS:0000000000000000
CS:  0010 DS: 0000 ES: 0000 CR0: 0000000080050033
CR2: 0000000000738000 CR3: 000000004b960000 CR4: 00000000001426e0
DR0: 0000000000000000 DR1: 0000000000000000 DR2: 0000000000000000
DR3: 0000000000000000 DR6: 00000000fffe0ff0 DR7: 0000000000000400