Message-ID: <CAKFNMo=EA9GHn8LehR8kbgs+z92G5v=FCmTcafwjtnV3+T3AOA@mail.gmail.com>
Date: Sun, 5 May 2024 03:26:33 +0900
From: Ryusuke Konishi <konishi.ryusuke@...il.com>
To: syzbot <syzbot+d3abed1ad3d367fa2627@...kaller.appspotmail.com>
Cc: linux-fsdevel@...r.kernel.org, linux-kernel@...r.kernel.org, 
	linux-nilfs@...r.kernel.org, syzkaller-bugs@...glegroups.com
Subject: Re: [syzbot] [nilfs?] kernel BUG in __block_write_begin_int (2)

On Sat, May 4, 2024 at 7:20 PM syzbot wrote:
>
> Hello,
>
> syzbot found the following issue on:
>
> HEAD commit:    9e4bc4bcae01 Merge tag 'nfs-for-6.9-2' of git://git.linux-..
> git tree:       upstream
> console+strace: https://syzkaller.appspot.com/x/log.txt?x=12f2ae87180000
> kernel config:  https://syzkaller.appspot.com/x/.config?x=3714fc09f933e505
> dashboard link: https://syzkaller.appspot.com/bug?extid=d3abed1ad3d367fa2627
> 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=150c697f180000
> C reproducer:   https://syzkaller.appspot.com/x/repro.c?x=140de537180000
>
> Downloadable assets:
> disk image: https://storage.googleapis.com/syzbot-assets/b98a742ff5ed/disk-9e4bc4bc.raw.xz
> vmlinux: https://storage.googleapis.com/syzbot-assets/207a8191df7c/vmlinux-9e4bc4bc.xz
> kernel image: https://storage.googleapis.com/syzbot-assets/7dd86c3ad0ba/bzImage-9e4bc4bc.xz
> mounted in repro: https://storage.googleapis.com/syzbot-assets/d35001c4b748/mount_0.gz
>
> Bisection is inconclusive: the issue happens on the oldest tested release.
>
> bisection log:  https://syzkaller.appspot.com/x/bisect.txt?x=15526d37180000
> final oops:     https://syzkaller.appspot.com/x/report.txt?x=17526d37180000
> console output: https://syzkaller.appspot.com/x/log.txt?x=13526d37180000
>
> IMPORTANT: if you fix the issue, please add the following tag to the commit:
> Reported-by: syzbot+d3abed1ad3d367fa2627@...kaller.appspotmail.com
>
> ------------[ cut here ]------------
> kernel BUG at fs/buffer.c:2083!
> invalid opcode: 0000 [#1] PREEMPT SMP KASAN NOPTI
> CPU: 0 PID: 5084 Comm: syz-executor283 Not tainted 6.9.0-rc6-syzkaller-00012-g9e4bc4bcae01 #0
> Hardware name: Google Google Compute Engine/Google Compute Engine, BIOS Google 03/27/2024
> RIP: 0010:__block_write_begin_int+0x19a7/0x1a70 fs/buffer.c:2083
> Code: 31 ff e8 ac 35 78 ff 48 89 d8 48 25 ff 0f 00 00 74 27 e8 bc 30 78 ff e9 c6 e7 ff ff e8 b2 30 78 ff 90 0f 0b e8 aa 30 78 ff 90 <0f> 0b e8 a2 30 78 ff 90 0f 0b e8 ca 5d 62 09 48 8b 5c 24 08 48 89
> RSP: 0018:ffffc90003327760 EFLAGS: 00010293
> RAX: ffffffff821ddf06 RBX: 0000000000007b54 RCX: ffff88802eff3c00
> RDX: 0000000000000000 RSI: 0000000000001000 RDI: 0000000000007b54
> RBP: ffffc900033278c8 R08: ffffffff821dc733 R09: 1ffffd400006f810
> R10: dffffc0000000000 R11: fffff9400006f811 R12: 00fff0000000920d
> R13: 0000000000000000 R14: 0000000000001000 R15: 0000000000007b54
> FS:  000055556494d480(0000) GS:ffff8880b9400000(0000) knlGS:0000000000000000
> CS:  0010 DS: 0000 ES: 0000 CR0: 0000000080050033
> CR2: 000055838a10d7f0 CR3: 0000000078508000 CR4: 0000000000350ef0
> Call Trace:
>  <TASK>
>  nilfs_prepare_chunk fs/nilfs2/dir.c:86 [inline]
>  nilfs_set_link+0xc5/0x2a0 fs/nilfs2/dir.c:411
>  nilfs_rename+0x5b2/0xaf0 fs/nilfs2/namei.c:416
>  vfs_rename+0xbdd/0xf00 fs/namei.c:4880
>  do_renameat2+0xd94/0x13f0 fs/namei.c:5037
>  __do_sys_rename fs/namei.c:5084 [inline]
>  __se_sys_rename fs/namei.c:5082 [inline]
>  __x64_sys_rename+0x86/0xa0 fs/namei.c:5082
>  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: 0033:0x7fa292c67f99
> Code: 28 00 00 00 75 05 48 83 c4 28 c3 e8 f1 17 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:00007ffd9d3b0198 EFLAGS: 00000246 ORIG_RAX: 0000000000000052
> RAX: ffffffffffffffda RBX: 0000000000000000 RCX: 00007fa292c67f99
> RDX: 00007fa292c67f99 RSI: 0000000020000040 RDI: 0000000020000180
> RBP: 0000000000000000 R08: 00007ffd9d3b01d0 R09: 00007ffd9d3b01d0
> R10: 0000000000000f69 R11: 0000000000000246 R12: 00007ffd9d3b01d0
> R13: 00007ffd9d3b0458 R14: 431bde82d7b634db R15: 00007fa292cb103b
>  </TASK>
> Modules linked in:
> ---[ end trace 0000000000000000 ]---
> RIP: 0010:__block_write_begin_int+0x19a7/0x1a70 fs/buffer.c:2083
> Code: 31 ff e8 ac 35 78 ff 48 89 d8 48 25 ff 0f 00 00 74 27 e8 bc 30 78 ff e9 c6 e7 ff ff e8 b2 30 78 ff 90 0f 0b e8 aa 30 78 ff 90 <0f> 0b e8 a2 30 78 ff 90 0f 0b e8 ca 5d 62 09 48 8b 5c 24 08 48 89
> RSP: 0018:ffffc90003327760 EFLAGS: 00010293
> RAX: ffffffff821ddf06 RBX: 0000000000007b54 RCX: ffff88802eff3c00
> RDX: 0000000000000000 RSI: 0000000000001000 RDI: 0000000000007b54
> RBP: ffffc900033278c8 R08: ffffffff821dc733 R09: 1ffffd400006f810
> R10: dffffc0000000000 R11: fffff9400006f811 R12: 00fff0000000920d
> R13: 0000000000000000 R14: 0000000000001000 R15: 0000000000007b54
> FS:  000055556494d480(0000) GS:ffff8880b9500000(0000) knlGS:0000000000000000
> CS:  0010 DS: 0000 ES: 0000 CR0: 0000000080050033
> CR2: 000055838a039e38 CR3: 0000000078508000 CR4: 0000000000350ef0
>
>
> ---
> This report is generated by a bot. It may contain errors.
> See https://goo.gl/tpsmEJ for more information about syzbot.
> syzbot engineers can be reached at syzkaller@...glegroups.com.
>
> syzbot will keep track of this issue. See:
> https://goo.gl/tpsmEJ#status for how to communicate with syzbot.
> For information about bisection process see: https://goo.gl/tpsmEJ#bisection
>
> If the report is already addressed, let syzbot know by replying with:
> #syz fix: exact-commit-title
>
> If you want syzbot to run the reproducer, reply with:
> #syz test: git://repo/address.git branch-or-commit-hash
> If you attach or paste a git patch, syzbot will apply it before testing.
>
> If you want to overwrite report's subsystems, reply with:
> #syz set subsystems: new-subsystem
> (See the list of subsystem names on the web dashboard)
>
> If the report is a duplicate of another one, reply with:
> #syz dup: exact-subject-of-another-report
>
> If you want to undo deduplication, reply with:
> #syz undup

This appears to be an issue with the same cause as the automatically
obsoleted issue below:

https://syzkaller.appspot.com/bug?extid=4936b06b07f365af31cc

I would like to take a closer look.

Ryusuke Konishi

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