[syzbot] [nilfs?] kernel BUG in nilfs_delete_entry

[syzbot]

Hello,

syzbot found the following issue on:

HEAD commit: 5eb4573ea63d Merge tag 'soc-fixes-6.9-2' of git://git.kern..
git tree: upstream
console output: https://syzkaller.appspot.com/x/log.txt?x=1591a5e8980000
kernel config: https://syzkaller.appspot.com/x/.config?x=3d46aa9d7a44f40d
dashboard link: https://syzkaller.appspot.com/bug?extid=32c3706ebf5d95046ea1
compiler: Debian clang version 15.0.6, GNU ld (GNU Binutils for Debian) 2.40
syz repro: https://syzkaller.appspot.com/x/repro.syz?x=1213956b180000
C reproducer: https://syzkaller.appspot.com/x/repro.c?x=13ac32ef180000

Downloadable assets:
disk image: https://storage.googleapis.com/syzbot-assets/7e4c1378cbb1/disk-5eb4573e.raw.xz
vmlinux: https://storage.googleapis.com/syzbot-assets/8e4487ecdd86/vmlinux-5eb4573e.xz
kernel image: https://storage.googleapis.com/syzbot-assets/d84518ee028f/bzImage-5eb4573e.xz
mounted in repro #1: https://storage.googleapis.com/syzbot-assets/350446baf90d/mount_0.gz
mounted in repro #2: https://storage.googleapis.com/syzbot-assets/e66542e7352f/mount_2.gz

The issue was bisected to:

commit 602ce7b8e1343b19c0cf93a3dd1926838ac5a1cc
Author: Ryusuke Konishi <konishi...@gmail.com>
Date: Fri Jan 27 13:22:02 2023 +0000

nilfs2: prevent WARNING in nilfs_dat_commit_end()

bisection log: https://syzkaller.appspot.com/x/bisect.txt?x=15d757d8980000
final oops: https://syzkaller.appspot.com/x/report.txt?x=17d757d8980000
console output: https://syzkaller.appspot.com/x/log.txt?x=13d757d8980000

IMPORTANT: if you fix the issue, please add the following tag to the commit:
Reported-by: syzbot+32c370...@syzkaller.appspotmail.com
Fixes: 602ce7b8e134 ("nilfs2: prevent WARNING in nilfs_dat_commit_end()")

------------[ cut here ]------------
kernel BUG at fs/nilfs2/dir.c:545!
invalid opcode: 0000 [#1] PREEMPT SMP KASAN PTI
CPU: 1 PID: 5115 Comm: syz-executor410 Not tainted 6.9.0-rc5-syzkaller-00296-g5eb4573ea63d #0
Hardware name: Google Google Compute Engine/Google Compute Engine, BIOS Google 03/27/2024
RIP: 0010:nilfs_delete_entry+0x349/0x350 fs/nilfs2/dir.c:545
Code: 8d fe e9 de fd ff ff 44 89 f9 80 e1 07 fe c1 38 c1 0f 8c 20 ff ff ff 4c 89 ff e8 f2 a6 8d fe e9 13 ff ff ff e8 68 56 2c fe 90 <0f> 0b 0f 1f 44 00 00 90 90 90 90 90 90 90 90 90 90 90 90 90 90 90
RSP: 0018:ffffc900036078b8 EFLAGS: 00010293
RAX: ffffffff8369aa08 RBX: 0000000000000050 RCX: ffff888018339e00
RDX: 0000000000000000 RSI: 00000000fffffffb RDI: 0000000000000000
RBP: 00000000fffffffb R08: ffffffff8369a8de R09: 1ffff1100806d722
R10: dffffc0000000000 R11: ffffed100806d723 R12: ffffea00010fed80
R13: ffff888043fb6038 R14: 0000000000000020 R15: ffff888043fb6020
FS: 00007fa2992ee6c0(0000) GS:ffff8880b9500000(0000) knlGS:0000000000000000
CS: 0010 DS: 0000 ES: 0000 CR0: 0000000080050033
CR2: 00007ffd3dbd8b98 CR3: 0000000024b86000 CR4: 00000000003506f0
DR0: 0000000000000000 DR1: 0000000000000000 DR2: 0000000000000000
DR3: 0000000000000000 DR6: 00000000fffe0ff0 DR7: 0000000000000400
Call Trace:
<TASK>
nilfs_rename+0x57d/0xaf0 fs/nilfs2/namei.c:413
vfs_rename+0xbdb/0xf00 fs/namei.c:4880
do_renameat2+0xd94/0x13f0 fs/namei.c:5037
__do_sys_renameat2 fs/namei.c:5071 [inline]
__se_sys_renameat2 fs/namei.c:5068 [inline]
__x64_sys_renameat2+0xd2/0xf0 fs/namei.c:5068
do_syscall_x64 arch/x86/entry/common.c:52 [inline]
do_syscall_64+0xf5/0x240 arch/x86/entry/common.c:83
entry_SYSCALL_64_after_hwframe+0x77/0x7f
RIP: 0033:0x7fa299358f49
Code: 28 00 00 00 75 05 48 83 c4 28 c3 e8 b1 18 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 b0 ff ff ff f7 d8 64 89 01 48
RSP: 002b:00007fa2992ee218 EFLAGS: 00000246 ORIG_RAX: 000000000000013c
RAX: ffffffffffffffda RBX: 00007fa2993e16d8 RCX: 00007fa299358f49
RDX: 0000000000000006 RSI: 0000000020000100 RDI: 0000000000000005
RBP: 00007fa2993e16d0 R08: 0000000000000000 R09: 0000000000000000
R10: 0000000020000580 R11: 0000000000000246 R12: 00007fa2993ade20
R13: 00007fa2993adb68 R14: 0030656c69662f2e R15: 3e2efc42dc31fca1
</TASK>
Modules linked in:
---[ end trace 0000000000000000 ]---
RIP: 0010:nilfs_delete_entry+0x349/0x350 fs/nilfs2/dir.c:545
Code: 8d fe e9 de fd ff ff 44 89 f9 80 e1 07 fe c1 38 c1 0f 8c 20 ff ff ff 4c 89 ff e8 f2 a6 8d fe e9 13 ff ff ff e8 68 56 2c fe 90 <0f> 0b 0f 1f 44 00 00 90 90 90 90 90 90 90 90 90 90 90 90 90 90 90
RSP: 0018:ffffc900036078b8 EFLAGS: 00010293

RAX: ffffffff8369aa08 RBX: 0000000000000050 RCX: ffff888018339e00
RDX: 0000000000000000 RSI: 00000000fffffffb RDI: 0000000000000000
RBP: 00000000fffffffb R08: ffffffff8369a8de R09: 1ffff1100806d722
R10: dffffc0000000000 R11: ffffed100806d723 R12: ffffea00010fed80
R13: ffff888043fb6038 R14: 0000000000000020 R15: ffff888043fb6020
FS: 00007fa2992ee6c0(0000) GS:ffff8880b9400000(0000) knlGS:0000000000000000
CS: 0010 DS: 0000 ES: 0000 CR0: 0000000080050033
CR2: 00007fa2993149f0 CR3: 0000000024b86000 CR4: 00000000003506f0
DR0: 0000000000000000 DR1: 0000000000000000 DR2: 0000000000000000
DR3: 0000000000000000 DR6: 00000000fffe0ff0 DR7: 0000000000000400


---
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[Ryusuke Konishi]

According to the stack trace, syzbot was hitting a legacy part that
uses BUG_ON() instead of returning errors in the directory code, so I
would like to fix it to cover this.

The bisected commit itself detects metadata corruption generated by
syzbot and handles it as an error, so it doesn't seem to be a problem.
I'm guessing that the commit just affected reproducibility.

Ryusuke Konishi