BUG: unable to handle kernel NULL pointer dereference at 0000000000000000
PGD 8f6b2067 P4D 8f6b2067 PUD 75122067 PMD 0 
Oops: 0010 [#1] PREEMPT SMP KASAN
CPU: 0 PID: 25513 Comm: syz-executor.3 Not tainted 4.19.78 #0
Hardware name: Google Google Compute Engine/Google Compute Engine, BIOS Google 01/01/2011
RIP: 0010:          (null)
Code: Bad RIP value.
RSP: 0018:ffff8880636579f0 EFLAGS: 00010246
RAX: ffffffff875b0f20 RBX: 0000000000000000 RCX: 0000000000000018
RDX: 0000000000000000 RSI: ffff888078b5c630 RDI: ffff8880a0847000
RBP: ffff888063657b08 R08: 0000000000000000 R09: ffff888063657a80
R10: 0000000000000000 R11: 0000000000000000 R12: 0000000000000018
R13: ffff888063657ae0 R14: ffff888063657d48 R15: ffff888078b5c630
FS:  00007fe3a0b15700(0000) GS:ffff8880ae800000(0000) knlGS:0000000000000000
CS:  0010 DS: 0000 ES: 0000 CR0: 0000000080050033
CR2: ffffffffffffffd6 CR3: 000000009780a000 CR4: 00000000001406f0
DR0: 0000000000000000 DR1: 0000000000000000 DR2: 0000000000000000
DR3: 0000000000000000 DR6: 00000000fffe0ff0 DR7: 0000000000000400
Call Trace:
 generic_perform_write+0x22a/0x520 mm/filemap.c:3161
 __generic_file_write_iter+0x25e/0x630 mm/filemap.c:3286
 ext4_file_write_iter+0x32b/0x1060 fs/ext4/file.c:270
 call_write_iter include/linux/fs.h:1820 [inline]
 new_sync_write fs/read_write.c:474 [inline]
 __vfs_write+0x587/0x810 fs/read_write.c:487
 vfs_write+0x20c/0x560 fs/read_write.c:549
 ksys_write+0x14f/0x2d0 fs/read_write.c:599
 __do_sys_write fs/read_write.c:611 [inline]
 __se_sys_write fs/read_write.c:608 [inline]
 __x64_sys_write+0x73/0xb0 fs/read_write.c:608
 do_syscall_64+0xfd/0x620 arch/x86/entry/common.c:293
 entry_SYSCALL_64_after_hwframe+0x49/0xbe
RIP: 0033:0x459a59
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:00007fe3a0b14c78 EFLAGS: 00000246 ORIG_RAX: 0000000000000001
RAX: ffffffffffffffda RBX: 0000000000000003 RCX: 0000000000459a59
RDX: 0000000000000018 RSI: 00000000200000c0 RDI: 0000000000000003
RBP: 000000000075bf20 R08: 0000000000000000 R09: 0000000000000000
R10: 0000000000000000 R11: 0000000000000246 R12: 00007fe3a0b156d4
R13: 00000000004c9fc5 R14: 00000000004e1c58 R15: 00000000ffffffff
Modules linked in:
CR2: 0000000000000000
---[ end trace 367b7440de6f1704 ]---
RIP: 0010:          (null)
kobject: 'loop2' (00000000ac17210e): kobject_uevent_env
Code: Bad RIP value.
kobject: 'loop2' (00000000ac17210e): fill_kobj_path: path = '/devices/virtual/block/loop2'
kobject: 'loop5' (000000008be9f1fc): kobject_uevent_env
kobject: 'loop5' (000000008be9f1fc): fill_kobj_path: path = '/devices/virtual/block/loop5'
RSP: 0018:ffff8880636579f0 EFLAGS: 00010246
RAX: ffffffff875b0f20 RBX: 0000000000000000 RCX: 0000000000000018
RDX: 0000000000000000 RSI: ffff888078b5c630 RDI: ffff8880a0847000
EXT4-fs (sda1): re-mounted. Opts: 
RBP: ffff888063657b08 R08: 0000000000000000 R09: ffff888063657a80
R10: 0000000000000000 R11: 0000000000000000 R12: 0000000000000018
kobject: 'loop5' (000000008be9f1fc): kobject_uevent_env
kobject: 'loop5' (000000008be9f1fc): fill_kobj_path: path = '/devices/virtual/block/loop5'
R13: ffff888063657ae0 R14: ffff888063657d48 R15: ffff888078b5c630
FS:  00007fe3a0b15700(0000) GS:ffff8880ae800000(0000) knlGS:0000000000000000
CS:  0010 DS: 0000 ES: 0000 CR0: 0000000080050033
kobject: 'loop2' (00000000ac17210e): kobject_uevent_env
CR2: 00007ffdc4141d8c CR3: 000000009780a000 CR4: 00000000001406f0
kobject: 'loop2' (00000000ac17210e): fill_kobj_path: path = '/devices/virtual/block/loop2'
DR0: 0000000000000000 DR1: 0000000000000000 DR2: 0000000000000000
kobject: 'loop5' (000000008be9f1fc): kobject_uevent_env
kobject: 'loop5' (000000008be9f1fc): kobject_uevent_env
kobject: 'loop5' (000000008be9f1fc): fill_kobj_path: path = '/devices/virtual/block/loop5'
DR3: 0000000000000000 DR6: 00000000fffe0ff0 DR7: 0000000000000400
kobject: 'loop5' (000000008be9f1fc): fill_kobj_path: path = '/devices/virtual/block/loop5'