Re: [syzbot] [bcachefs?] WARNING in bchfs_truncate

[syzbot <syzbot+247ac87eabcb1f8fa990@syzkaller.appspotmail.com>]

syzbot has found a reproducer for the following issue on:

HEAD commit:    b6394d6f7159 Merge tag 'pull-misc' of git://git.kernel.org..
git tree:       upstream
console output: https://syzkaller.appspot.com/x/log.txt?x=159d0210980000
kernel config:  https://syzkaller.appspot.com/x/.config?x=713476114e57eef3
dashboard link: https://syzkaller.appspot.com/bug?extid=247ac87eabcb1f8fa990
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=15c61a0c980000

Downloadable assets:
disk image: https://storage.googleapis.com/syzbot-assets/e8e1377d4772/disk-b6394d6f.raw.xz
vmlinux: https://storage.googleapis.com/syzbot-assets/19fbbb3b6dd5/vmlinux-b6394d6f.xz
kernel image: https://storage.googleapis.com/syzbot-assets/4dcce16af95d/bzImage-b6394d6f.xz
mounted in repro: https://storage.googleapis.com/syzbot-assets/fea098faf1eb/mount_0.gz

IMPORTANT: if you fix the issue, please add the following tag to the commit:
Reported-by: syzbot+247ac87eabcb1f8fa990@syzkaller.appspotmail.com

bcachefs (loop2): resume_logged_ops... done
bcachefs (loop2): going read-write
bcachefs (loop2): done starting filesystem
------------[ cut here ]------------
truncate spotted in mem i_size < btree i_size: 1 < 33554432
WARNING: CPU: 0 PID: 15517 at fs/bcachefs/fs-io.c:440 bchfs_truncate+0xb79/0xc80 fs/bcachefs/fs-io.c:437
Modules linked in:
CPU: 0 PID: 15517 Comm: syz-executor.2 Not tainted 6.9.0-syzkaller-10729-gb6394d6f7159 #0
Hardware name: Google Google Compute Engine/Google Compute Engine, BIOS Google 04/02/2024
RIP: 0010:bchfs_truncate+0xb79/0xc80 fs/bcachefs/fs-io.c:437
Code: 00 fc ff df 80 3c 03 00 74 08 4c 89 e7 e8 ff 28 d2 fd 48 8b 94 24 f8 00 00 00 48 c7 c7 00 98 12 8c 4c 89 f6 e8 38 b9 31 fd 90 <0f> 0b 90 90 e9 8c f9 ff ff e8 39 9f 6f fd 48 8b 5c 24 60 48 89 df
RSP: 0018:ffffc900038c7520 EFLAGS: 00010246
RAX: c2b55e02655caf00 RBX: 1ffff92000718ec3 RCX: ffff88807bd6da00
RDX: 0000000000000000 RSI: 0000000000000001 RDI: 0000000000000000
RBP: ffffc900038c7758 R08: ffffffff815856f2 R09: fffffbfff1c3996c
R10: dffffc0000000000 R11: fffffbfff1c3996c R12: ffffc900038c7618
R13: ffff8880772676d0 R14: 0000000000000001 R15: ffff888077267bc8
FS:  00007f7f358766c0(0000) GS:ffff8880b9400000(0000) knlGS:0000000000000000
CS:  0010 DS: 0000 ES: 0000 CR0: 0000000080050033
CR2: 00007fe610e2e6c0 CR3: 00000000ac338000 CR4: 00000000003506f0
DR0: 0000000000000000 DR1: 0000000000000000 DR2: 0000000000000000
DR3: 0000000000000000 DR6: 00000000fffe0ff0 DR7: 0000000000000400
Call Trace:
 <TASK>
 notify_change+0xb9d/0xe70 fs/attr.c:497
 do_truncate+0x220/0x310 fs/open.c:65
 handle_truncate fs/namei.c:3308 [inline]
 do_open fs/namei.c:3654 [inline]
 path_openat+0x2a3d/0x3280 fs/namei.c:3807
 do_filp_open+0x235/0x490 fs/namei.c:3834
 do_sys_openat2+0x13e/0x1d0 fs/open.c:1405
 do_sys_open fs/open.c:1420 [inline]
 __do_sys_openat fs/open.c:1436 [inline]
 __se_sys_openat fs/open.c:1431 [inline]
 __x64_sys_openat+0x247/0x2a0 fs/open.c:1431
 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: 0033:0x7f7f34a7cee9
Code: 28 00 00 00 75 05 48 83 c4 28 c3 e8 e1 20 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:00007f7f358760c8 EFLAGS: 00000246 ORIG_RAX: 0000000000000101
RAX: ffffffffffffffda RBX: 00007f7f34babf80 RCX: 00007f7f34a7cee9
RDX: 000000000000275a RSI: 0000000020000280 RDI: ffffffffffffff9c
RBP: 00007f7f34ac949e R08: 0000000000000000 R09: 0000000000000000
R10: 0000000000000000 R11: 0000000000000246 R12: 0000000000000000
R13: 000000000000000b R14: 00007f7f34babf80 R15: 00007ffcb18bb738
 </TASK>


---
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.