BUG: kernel NULL pointer dereference, address: 0000000000000000
#PF: supervisor instruction fetch in kernel mode
#PF: error_code(0x0010) - not-present page
PGD 77475067 P4D 77475067 PUD 778da067 PMD 0 
Oops: 0010 [#1] PREEMPT SMP KASAN
CPU: 0 PID: 20095 Comm: syz-executor.3 Not tainted 6.4.0-rc7-syzkaller-00019-g99ec1ed7c2ed #0
Hardware name: Google Google Compute Engine/Google Compute Engine, BIOS Google 05/27/2023
RIP: 0010:0x0
Code: Unable to access opcode bytes at 0xffffffffffffffd6.
RSP: 0018:ffffc900167c6c98 EFLAGS: 00010246
RAX: 0000000000000020 RBX: 0000000000000000 RCX: ffffffff8b25ac80
RDX: ffffc900167c7000 RSI: ffffc900167c6fe0 RDI: ffff8880286d3000
RBP: ffffc900167c71d0 R08: ffffffff834f9c5b R09: ffffed1010b84abb
R10: 0000000000000000 R11: dffffc0000000001 R12: 1ffff92002cf8e04
R13: dffffc0000000000 R14: ffffc900167c7001 R15: 0000000000000001
FS:  00007efe6abfe700(0000) GS:ffff8880b9800000(0000) knlGS:0000000000000000
CS:  0010 DS: 0000 ES: 0000 CR0: 0000000080050033
CR2: ffffffffffffffd6 CR3: 000000002d2fe000 CR4: 00000000003506f0
DR0: 0000000000000000 DR1: 0000000000000000 DR2: 0000000000000000
DR3: 0000000000000000 DR6: 00000000fffe0ff0 DR7: 0000000000000400
Call Trace:
 <TASK>
 nilfs_segctor_assign fs/nilfs2/segment.c:1651 [inline]
 nilfs_segctor_do_construct+0x39f1/0x6d30 fs/nilfs2/segment.c:2081
 nilfs_construct_dsync_segment+0x5c4/0x6c0 fs/nilfs2/segment.c:2335
 do_writepages+0x3a6/0x670 mm/page-writeback.c:2551
 filemap_fdatawrite_wbc+0x125/0x180 mm/filemap.c:390
 __filemap_fdatawrite_range mm/filemap.c:423 [inline]
 filemap_write_and_wait_range+0x1d4/0x2c0 mm/filemap.c:678
 __generic_file_write_iter+0x2c8/0x400 mm/filemap.c:4043
 generic_file_write_iter+0xaf/0x310 mm/filemap.c:4089
 do_iter_write+0x7b1/0xcb0 fs/read_write.c:860
 iter_file_splice_write+0x843/0xfe0 fs/splice.c:795
 do_splice_from fs/splice.c:873 [inline]
 direct_splice_actor+0xe7/0x1c0 fs/splice.c:1039
 splice_direct_to_actor+0x4c4/0xbd0 fs/splice.c:994
 do_splice_direct+0x283/0x3d0 fs/splice.c:1082
 do_sendfile+0x620/0xff0 fs/read_write.c:1254
 __do_sys_sendfile64 fs/read_write.c:1322 [inline]
 __se_sys_sendfile64+0x17c/0x1e0 fs/read_write.c:1308
 do_syscall_x64 arch/x86/entry/common.c:50 [inline]
 do_syscall_64+0x41/0xc0 arch/x86/entry/common.c:80
 entry_SYSCALL_64_after_hwframe+0x63/0xcd
RIP: 0033:0x7efe6c08c389
Code: 28 00 00 00 75 05 48 83 c4 28 c3 e8 f1 19 00 00 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 73 01 c3 48 c7 c1 b8 ff ff ff f7 d8 64 89 01 48
RSP: 002b:00007efe6abfe168 EFLAGS: 00000246 ORIG_RAX: 0000000000000028
RAX: ffffffffffffffda RBX: 00007efe6c1abf80 RCX: 00007efe6c08c389
RDX: 0000000000000000 RSI: 0000000000000004 RDI: 0000000000000004
RBP: 00007efe6c0d7493 R08: 0000000000000000 R09: 0000000000000000
R10: 0000000008802007 R11: 0000000000000246 R12: 0000000000000000
R13: 00007ffff4bc4bcf R14: 00007efe6abfe300 R15: 0000000000022000
 </TASK>
Modules linked in:
CR2: 0000000000000000
---[ end trace 0000000000000000 ]---
RIP: 0010:0x0
Code: Unable to access opcode bytes at 0xffffffffffffffd6.
RSP: 0018:ffffc900167c6c98 EFLAGS: 00010246
RAX: 0000000000000020 RBX: 0000000000000000 RCX: ffffffff8b25ac80
RDX: ffffc900167c7000 RSI: ffffc900167c6fe0 RDI: ffff8880286d3000
RBP: ffffc900167c71d0 R08: ffffffff834f9c5b R09: ffffed1010b84abb
R10: 0000000000000000 R11: dffffc0000000001 R12: 1ffff92002cf8e04
R13: dffffc0000000000 R14: ffffc900167c7001 R15: 0000000000000001
FS:  00007efe6abfe700(0000) GS:ffff8880b9800000(0000) knlGS:0000000000000000
CS:  0010 DS: 0000 ES: 0000 CR0: 0000000080050033
CR2: ffffffffffffffd6 CR3: 000000002d2fe000 CR4: 00000000003506f0
DR0: 0000000000000000 DR1: 0000000000000000 DR2: 0000000000000000
DR3: 0000000000000000 DR6: 00000000fffe0ff0 DR7: 0000000000000400