linux-kernel - [syzbot] [bcachefs?] kernel BUG in __bch2_trans

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Message-ID: <68bd8fc2.050a0220.192772.01da.GAE@google.com>
Date: Sun, 07 Sep 2025 06:59:30 -0700
From: syzbot <syzbot+3a42e4989f9047772c6d@...kaller.appspotmail.com>
To: kent.overstreet@...ux.dev, linux-bcachefs@...r.kernel.org, 
	linux-kernel@...r.kernel.org, syzkaller-bugs@...glegroups.com
Subject: [syzbot] [bcachefs?] kernel BUG in __bch2_trans_get

Hello,

syzbot found the following issue on:

HEAD commit:    08b06c30a445 Merge tag 'v6.17-rc4-ksmbd-fix' of git://git...
git tree:       upstream
console output: https://syzkaller.appspot.com/x/log.txt?x=128c4962580000
kernel config:  https://syzkaller.appspot.com/x/.config?x=385d836f07b5a70d
dashboard link: https://syzkaller.appspot.com/bug?extid=3a42e4989f9047772c6d
compiler:       Debian clang version 20.1.8 (++20250708063551+0c9f909b7976-1~exp1~20250708183702.136), Debian LLD 20.1.8

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

Downloadable assets:
disk image (non-bootable): https://storage.googleapis.com/syzbot-assets/d900f083ada3/non_bootable_disk-08b06c30.raw.xz
vmlinux: https://storage.googleapis.com/syzbot-assets/516e142f1f8b/vmlinux-08b06c30.xz
kernel image: https://storage.googleapis.com/syzbot-assets/a968d13b9737/bzImage-08b06c30.xz

IMPORTANT: if you fix the issue, please add the following tag to the commit:
Reported-by: syzbot+3a42e4989f9047772c6d@...kaller.appspotmail.com

bcachefs (loop0): /file0/file0 offset 0: data_read_io_err
  u64s 8 type extent 4099:8:U32_MAX len 8 ver 1: durability: 1 crc: c_size 8 size 8 offset 0 nonce 0 csum chacha20_poly1305_80 77fa:f532966a693125aa  compress incompressible ptr: 0:34:0 gen 0
bcachefs (loop0): /file0/file0 offset 0: data read error: data_read_io_err
bcachefs (loop0): /file0/file0 offset 0: data read error, data_read_io_err
  u64s 8 type extent 4099:8:U32_MAX len 8 ver 1: durability: 1 crc: c_size 8 size 8 offset 0 nonce 0 csum chacha20_poly1305_80 77fa:f532966a693125aa  compress incompressible ptr: 0:34:0 gen 0
  loop0 io error
------------[ cut here ]------------
kernel BUG at fs/bcachefs/btree_iter.c:3462!
Oops: invalid opcode: 0000 [#1] SMP KASAN NOPTI
CPU: 0 UID: 0 PID: 43 Comm: kworker/u4:3 Not tainted syzkaller #0 PREEMPT(full) 
Hardware name: QEMU Standard PC (Q35 + ICH9, 2009), BIOS 1.16.3-debian-1.16.3-2~bpo12+1 04/01/2014
Workqueue: events_unbound bch2_rbio_retry
RIP: 0010:__bch2_trans_get+0xce2/0xd80 fs/bcachefs/btree_iter.c:3460
Code: fd e9 81 f4 ff ff 44 89 f9 80 e1 07 80 c1 03 38 c1 0f 8c 9b fa ff ff 4c 89 ff e8 09 ca f9 fd e9 8e fa ff ff e8 5f d9 94 fd 90 <0f> 0b 44 89 e1 80 e1 07 80 c1 03 38 c1 0f 8c 45 fd ff ff 4c 89 e7
RSP: 0018:ffffc900005e7460 EFLAGS: 00010293
RAX: ffffffff842ae4a1 RBX: ffff888051f68000 RCX: ffff88801e8b0000
RDX: 0000000000000000 RSI: 0000000000000004 RDI: 0000000000000000
RBP: 0000000000000004 R08: ffffffff8fa3b637 R09: 1ffffffff1f476c6
R10: dffffc0000000000 R11: fffffbfff1f476c7 R12: ffff888052f84200
R13: 000000000000002b R14: dffffc0000000000 R15: ffff888051dd81d8
FS:  0000000000000000(0000) GS:ffff88808d20d000(0000) knlGS:0000000000000000
CS:  0010 DS: 0000 ES: 0000 CR0: 0000000080050033
CR2: 00007fec0a7d3fc8 CR3: 00000000305ea000 CR4: 0000000000352ef0
Call Trace:
 <TASK>
 bch2_rbio_retry+0x1d1/0x19b0 fs/bcachefs/io_read.c:594
 bch2_rbio_done fs/bcachefs/io_read.c:464 [inline]
 bch2_rbio_retry+0xbf4/0x19b0 fs/bcachefs/io_read.c:667
 process_one_work kernel/workqueue.c:3236 [inline]
 process_scheduled_works+0xae1/0x17b0 kernel/workqueue.c:3319
 worker_thread+0x8a0/0xda0 kernel/workqueue.c:3400
 kthread+0x70e/0x8a0 kernel/kthread.c:463
 ret_from_fork+0x3fc/0x770 arch/x86/kernel/process.c:148
 ret_from_fork_asm+0x1a/0x30 arch/x86/entry/entry_64.S:245
 </TASK>
Modules linked in:
---[ end trace 0000000000000000 ]---
RIP: 0010:__bch2_trans_get+0xce2/0xd80 fs/bcachefs/btree_iter.c:3460
Code: fd e9 81 f4 ff ff 44 89 f9 80 e1 07 80 c1 03 38 c1 0f 8c 9b fa ff ff 4c 89 ff e8 09 ca f9 fd e9 8e fa ff ff e8 5f d9 94 fd 90 <0f> 0b 44 89 e1 80 e1 07 80 c1 03 38 c1 0f 8c 45 fd ff ff 4c 89 e7
RSP: 0018:ffffc900005e7460 EFLAGS: 00010293
RAX: ffffffff842ae4a1 RBX: ffff888051f68000 RCX: ffff88801e8b0000


---
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