[syzbot] [bcachefs?] kernel BUG in bch2_bucket_alloc_freelist

[syzbot]

Hello,

syzbot found the following issue on:

HEAD commit: 2ccbdf43d5e7 Merge tag 'for-linus' of git://git.kernel.org..
git tree: upstream
console output: https://syzkaller.appspot.com/x/log.txt?x=15b13146980000
kernel config: https://syzkaller.appspot.com/x/.config?x=81c0d76ceef02b39
dashboard link: https://syzkaller.appspot.com/bug?extid=3d2944b5612507034fc4
compiler: gcc (Debian 12.2.0-14) 12.2.0, GNU ld (GNU Binutils for Debian) 2.40
userspace arch: i386

Unfortunately, I don't have any reproducer for this issue yet.

Downloadable assets:
disk image (non-bootable): https://storage.googleapis.com/syzbot-assets/7bc7510fe41f/non_bootable_disk-2ccbdf43.raw.xz
vmlinux: https://storage.googleapis.com/syzbot-assets/13cdb5bfbafa/vmlinux-2ccbdf43.xz
kernel image: https://storage.googleapis.com/syzbot-assets/7a14f5d07f81/bzImage-2ccbdf43.xz

IMPORTANT: if you fix the issue, please add the following tag to the commit:
Reported-by: syzbot+3d2944...@syzkaller.appspotmail.com

------------[ cut here ]------------
kernel BUG at fs/bcachefs/alloc_foreground.c:489!
Oops: invalid opcode: 0000 [#1] PREEMPT SMP KASAN NOPTI
CPU: 3 PID: 5534 Comm: syz-executor.2 Not tainted 6.10.0-rc3-syzkaller-00044-g2ccbdf43d5e7 #0
Hardware name: QEMU Standard PC (Q35 + ICH9, 2009), BIOS 1.16.2-debian-1.16.2-1 04/01/2014
RIP: 0010:bch2_bucket_alloc_freelist+0xec0/0x1090 fs/bcachefs/alloc_foreground.c:489
Code: ff ff 48 8b bd 18 fe ff ff e8 7c ba 0a fe e9 19 f9 ff ff 48 8b bd 88 fe ff ff e8 db b9 0a fe e9 55 f9 ff ff e8 91 87 ad fd 90 <0f> 0b 4c 89 ef e8 c6 b9 0a fe e9 25 f8 ff ff 48 89 cf e8 e9 b9 0a
RSP: 0018:ffffc90007fde1a0 EFLAGS: 00010246
RAX: 0000000000040000 RBX: 0000000000000019 RCX: ffffc90002f22000
RDX: 0000000000040000 RSI: ffffffff83e1083f RDI: 0000000000000007
RBP: ffffc90007fde3d0 R08: ffff8880217ce120 R09: 0000000000000000
R10: 0000000000000019 R11: 0000000000000001 R12: ffff8880217ce000
R13: ffff8880217ce2f8 R14: ffff88802bb94042 R15: dffffc0000000000
FS: 0000000000000000(0000) GS:ffff88802c300000(0063) knlGS:00000000f5f32b40
CS: 0010 DS: 002b ES: 002b CR0: 0000000080050033
CR2: 0000000031c3b000 CR3: 0000000053c02000 CR4: 0000000000352ef0
DR0: 0000000000000000 DR1: 0000000000000000 DR2: 0000000000000000
DR3: 0000000000000000 DR6: 00000000fffe0ff0 DR7: 0000000000000400
Call Trace:
<TASK>
bch2_bucket_alloc_trans+0x706/0xb20 fs/bcachefs/alloc_foreground.c:649
bch2_bucket_alloc_set_trans+0x466/0xd40 fs/bcachefs/alloc_foreground.c:810
__open_bucket_add_buckets+0x991/0x12f0 fs/bcachefs/alloc_foreground.c:1058
open_bucket_add_buckets+0x116/0x200 fs/bcachefs/alloc_foreground.c:1102
bch2_alloc_sectors_start_trans+0xa41/0x1ba0 fs/bcachefs/alloc_foreground.c:1457
__bch2_btree_node_alloc+0x718/0xdc0 fs/bcachefs/btree_update_interior.c:333
bch2_btree_reserve_get+0x21d/0x330 fs/bcachefs/btree_update_interior.c:547
bch2_btree_update_start+0x1235/0x1ed0 fs/bcachefs/btree_update_interior.c:1245
bch2_btree_split_leaf+0xc9/0x770 fs/bcachefs/btree_update_interior.c:1851
bch2_trans_commit_error+0x327/0xd00 fs/bcachefs/btree_trans_commit.c:918
__bch2_trans_commit+0x383b/0x7a40 fs/bcachefs/btree_trans_commit.c:1138
bch2_trans_commit fs/bcachefs/btree_update.h:170 [inline]
bch2_logged_op_start+0x122/0x1b0 fs/bcachefs/logged_ops.c:83
bch2_truncate+0x173/0x240 fs/bcachefs/io_misc.c:291
bchfs_truncate+0x90c/0xd70 fs/bcachefs/fs-io.c:476
bch2_setattr+0x1ab/0x250 fs/bcachefs/fs.c:918
notify_change+0x742/0x11f0 fs/attr.c:497
do_truncate+0x15c/0x220 fs/open.c:65
handle_truncate fs/namei.c:3308 [inline]
do_open fs/namei.c:3654 [inline]
path_openat+0x2505/0x29f0 fs/namei.c:3807
do_filp_open+0x1dc/0x430 fs/namei.c:3834
do_sys_openat2+0x17a/0x1e0 fs/open.c:1405
do_sys_open fs/open.c:1420 [inline]
__do_compat_sys_openat fs/open.c:1480 [inline]
__se_compat_sys_openat fs/open.c:1478 [inline]
__ia32_compat_sys_openat+0x16e/0x210 fs/open.c:1478
do_syscall_32_irqs_on arch/x86/entry/common.c:165 [inline]
__do_fast_syscall_32+0x73/0x120 arch/x86/entry/common.c:386
do_fast_syscall_32+0x32/0x80 arch/x86/entry/common.c:411
entry_SYSENTER_compat_after_hwframe+0x84/0x8e
RIP: 0023:0xf7340579
Code: b8 01 10 06 03 74 b4 01 10 07 03 74 b0 01 10 08 03 74 d8 01 00 00 00 00 00 00 00 00 00 00 00 00 00 51 52 55 89 e5 0f 34 cd 80 <5d> 5a 59 c3 90 90 90 90 8d b4 26 00 00 00 00 8d b4 26 00 00 00 00
RSP: 002b:00000000f5f325ac EFLAGS: 00000292 ORIG_RAX: 0000000000000127
RAX: ffffffffffffffda RBX: 00000000ffffff9c RCX: 0000000020000080
RDX: 0000000000183341 RSI: 0000000000000000 RDI: 0000000000000000
RBP: 0000000000000000 R08: 0000000000000000 R09: 0000000000000000
R10: 0000000000000000 R11: 0000000000000292 R12: 0000000000000000
R13: 0000000000000000 R14: 0000000000000000 R15: 0000000000000000
</TASK>
Modules linked in:
---[ end trace 0000000000000000 ]---
RIP: 0010:bch2_bucket_alloc_freelist+0xec0/0x1090 fs/bcachefs/alloc_foreground.c:489
Code: ff ff 48 8b bd 18 fe ff ff e8 7c ba 0a fe e9 19 f9 ff ff 48 8b bd 88 fe ff ff e8 db b9 0a fe e9 55 f9 ff ff e8 91 87 ad fd 90 <0f> 0b 4c 89 ef e8 c6 b9 0a fe e9 25 f8 ff ff 48 89 cf e8 e9 b9 0a
RSP: 0018:ffffc90007fde1a0 EFLAGS: 00010246
RAX: 0000000000040000 RBX: 0000000000000019 RCX: ffffc90002f22000
RDX: 0000000000040000 RSI: ffffffff83e1083f RDI: 0000000000000007
RBP: ffffc90007fde3d0 R08: ffff8880217ce120 R09: 0000000000000000
R10: 0000000000000019 R11: 0000000000000001 R12: ffff8880217ce000
R13: ffff8880217ce2f8 R14: ffff88802bb94042 R15: dffffc0000000000
FS: 0000000000000000(0000) GS:ffff88802c200000(0063) knlGS:00000000f5f32b40
CS: 0010 DS: 002b ES: 002b CR0: 0000000080050033
CR2: 0000560e79cc7088 CR3: 0000000053c02000 CR4: 0000000000352ef0
DR0: 0000000000000000 DR1: 0000000000000000 DR2: 0000000000000000
DR3: 0000000000000000 DR6: 00000000fffe0ff0 DR7: 0000000000000400
----------------
Code disassembly (best guess), 2 bytes skipped:
0: 10 06 adc %al,(%rsi)
2: 03 74 b4 01 add 0x1(%rsp,%rsi,4),%esi
6: 10 07 adc %al,(%rdi)
8: 03 74 b0 01 add 0x1(%rax,%rsi,4),%esi
c: 10 08 adc %cl,(%rax)
e: 03 74 d8 01 add 0x1(%rax,%rbx,8),%esi
1e: 00 51 52 add %dl,0x52(%rcx)
21: 55 push %rbp
22: 89 e5 mov %esp,%ebp
24: 0f 34 sysenter
26: cd 80 int $0x80
* 28: 5d pop %rbp <-- trapping instruction
29: 5a pop %rdx
2a: 59 pop %rcx
2b: c3 ret
2c: 90 nop
2d: 90 nop
2e: 90 nop
2f: 90 nop
30: 8d b4 26 00 00 00 00 lea 0x0(%rsi,%riz,1),%esi
37: 8d b4 26 00 00 00 00 lea 0x0(%rsi,%riz,1),%esi


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[Kent Overstreet]

On Sun, Jun 23, 2024 at 02:23:21AM -0700, syzbot wrote:
> Hello,
>
> syzbot found the following issue on:
>
> HEAD commit: 2ccbdf43d5e7 Merge tag 'for-linus' of git://git.kernel.org..
> git tree: upstream
> console output: https://syzkaller.appspot.com/x/log.txt?x=15b13146980000
> kernel config: https://syzkaller.appspot.com/x/.config?x=81c0d76ceef02b39
> dashboard link: https://syzkaller.appspot.com/bug?extid=3d2944b5612507034fc4
> compiler: gcc (Debian 12.2.0-14) 12.2.0, GNU ld (GNU Binutils for Debian) 2.40
> userspace arch: i386
>
> Unfortunately, I don't have any reproducer for this issue yet.
>
> Downloadable assets:
> disk image (non-bootable): https://storage.googleapis.com/syzbot-assets/7bc7510fe41f/non_bootable_disk-2ccbdf43.raw.xz
> vmlinux: https://storage.googleapis.com/syzbot-assets/13cdb5bfbafa/vmlinux-2ccbdf43.xz
> kernel image: https://storage.googleapis.com/syzbot-assets/7a14f5d07f81/bzImage-2ccbdf43.xz
>
> IMPORTANT: if you fix the issue, please add the following tag to the commit:
> Reported-by: syzbot+3d2944...@syzkaller.appspotmail.com
>
> ------------[ cut here ]------------
> kernel BUG at fs/bcachefs/alloc_foreground.c:489!

So it turns out, this one is from onlining a device (already a member of
the filesystem) that doesn't have a journal allocated; we end up using
bch2_bucket_alloc_new_fs() when we're not supposed to.

I started a rework of the early filesystem bringup allocation paths
awhile ago to get rid of that entirely, perhaps I shall finish that.