Message-ID: <68c0f729.050a0220.3c6139.0018.GAE@google.com>
Date: Tue, 09 Sep 2025 20:57:29 -0700
From: syzbot <syzbot+09fb21cd037d564c2519@...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?] WARNING in bch2_fs_journal_stop (2)

Hello,

syzbot found the following issue on:

HEAD commit:    76eeb9b8de98 Linux 6.17-rc5
git tree:       upstream
console output: https://syzkaller.appspot.com/x/log.txt?x=1033f962580000
kernel config:  https://syzkaller.appspot.com/x/.config?x=c7f605fd273c8220
dashboard link: https://syzkaller.appspot.com/bug?extid=09fb21cd037d564c2519
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-76eeb9b8.raw.xz
vmlinux: https://storage.googleapis.com/syzbot-assets/658515dceee8/vmlinux-76eeb9b8.xz
kernel image: https://storage.googleapis.com/syzbot-assets/ee40b9e4370a/bzImage-76eeb9b8.xz

IMPORTANT: if you fix the issue, please add the following tag to the commit:
Reported-by: syzbot+09fb21cd037d564c2519@...kaller.appspotmail.com

    hash_seed=fc917866faeb7b5b
    hash_type=siphash
    bi_size=1050
    bi_sectors=8
    bi_version=0
    bi_atime=2770562249
    bi_ctime=2770562249
    bi_mtime=2770562249
    bi_otime=2770562249
    bi_uid=0
    bi_gid=0
    bi_nlink=0
    bi_generation=0
    bi_dev=0
    bi_data_checksum=0
    bi_compression=0
    bi_project=0
    bi_background_compression=0
    bi_data_replicas=0
    bi_promote_target=0
    bi_foreground_target=0
    bi_background_target=0
    bi_erasure_code=0
    bi_fields_set=0
    bi_dir=4098
    bi_dir_offset=8977922886548783724
    bi_subvol=0
    bi_parent_subvol=0
    bi_nocow=0
    bi_depth=0
    bi_inodes_32bit=0
    bi_casefold=0, fixing
 done
bcachefs (da441363-bb6a-4ab9-999b-c1f40db4fee2): resume_logged_ops... done
bcachefs (da441363-bb6a-4ab9-999b-c1f40db4fee2): delete_dead_inodes... done
bcachefs (da441363-bb6a-4ab9-999b-c1f40db4fee2): Fixed errors, running fsck a second time to verify fs is clean
bcachefs (da441363-bb6a-4ab9-999b-c1f40db4fee2): check_extents_to_backpointers...
bcachefs (da441363-bb6a-4ab9-999b-c1f40db4fee2): scanning for missing backpointers in 1/128 buckets
 done
bcachefs (da441363-bb6a-4ab9-999b-c1f40db4fee2): check_inodes... done
bcachefs (da441363-bb6a-4ab9-999b-c1f40db4fee2): resume_logged_ops... done
bcachefs (da441363-bb6a-4ab9-999b-c1f40db4fee2): delete_dead_inodes... done
bcachefs (da441363-bb6a-4ab9-999b-c1f40db4fee2): done starting filesystem
bcachefs (loop0): shutting down
bcachefs (loop0): going read-only
bcachefs (loop0): finished waiting for writes to stop
bcachefs (loop0): flushing journal and stopping allocators, journal seq 24
bcachefs (loop0): flushing journal and stopping allocators complete, journal seq 24
------------[ cut here ]------------
journal shutdown error: cur seq 24 but last empty seq 23
WARNING: CPU: 0 PID: 5361 at fs/bcachefs/journal.c:1472 bch2_fs_journal_stop+0x42b/0x440 fs/bcachefs/journal.c:1468
Modules linked in:
CPU: 0 UID: 0 PID: 5361 Comm: syz.0.0 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
RIP: 0010:bch2_fs_journal_stop+0x42b/0x440 fs/bcachefs/journal.c:1468
Code: 44 24 30 42 80 3c 28 00 48 8b 5c 24 20 74 08 48 89 df e8 e8 65 d9 fd 48 8b 13 48 c7 c7 60 91 d5 8b 4c 89 e6 e8 86 01 38 fd 90 <0f> 0b 90 90 e9 e4 fe ff ff e8 07 be 30 07 0f 1f 80 00 00 00 00 90
RSP: 0018:ffffc9000d3a7540 EFLAGS: 00010246
RAX: 94147eeeb8664e00 RBX: ffff88805364aa28 RCX: ffff888031efa440
RDX: 0000000000000000 RSI: 0000000000000001 RDI: 0000000000000002
RBP: ffffc9000d3a7660 R08: ffff88801fc24253 R09: 1ffff11003f8484a
R10: dffffc0000000000 R11: ffffed1003f8484b R12: 0000000000000018
R13: dffffc0000000000 R14: ffff888053649800 R15: 1ffff1100a6c9300
FS:  0000000000000000(0000) GS:ffff88808d20c000(0000) knlGS:0000000000000000
CS:  0010 DS: 0000 ES: 0000 CR0: 0000000080050033
CR2: 00007f778139e000 CR3: 0000000051ee9000 CR4: 0000000000352ef0
Call Trace:
 <TASK>
 __bch2_fs_read_only+0x343/0x5b0 fs/bcachefs/super.c:306
 bch2_fs_read_only+0x42a/0xb00 fs/bcachefs/super.c:366
 __bch2_fs_stop+0x100/0x900 fs/bcachefs/super.c:677
 generic_shutdown_super+0x135/0x2c0 fs/super.c:643
 bch2_kill_sb+0x41/0x50 fs/bcachefs/fs.c:2618
 deactivate_locked_super+0xb9/0x130 fs/super.c:474
 cleanup_mnt+0x425/0x4c0 fs/namespace.c:1375
 task_work_run+0x1d1/0x260 kernel/task_work.c:227
 exit_task_work include/linux/task_work.h:40 [inline]
 do_exit+0x6b5/0x2300 kernel/exit.c:961
 do_group_exit+0x21c/0x2d0 kernel/exit.c:1102
 get_signal+0x1286/0x1340 kernel/signal.c:3034
 arch_do_signal_or_restart+0x9a/0x750 arch/x86/kernel/signal.c:337
 exit_to_user_mode_loop+0x75/0x110 kernel/entry/common.c:40
 exit_to_user_mode_prepare include/linux/irq-entry-common.h:225 [inline]
 syscall_exit_to_user_mode_work include/linux/entry-common.h:175 [inline]
 syscall_exit_to_user_mode include/linux/entry-common.h:210 [inline]
 do_syscall_64+0x2bd/0x3b0 arch/x86/entry/syscall_64.c:100
 entry_SYSCALL_64_after_hwframe+0x77/0x7f
RIP: 0033:0x7f5dff78ebe9
Code: Unable to access opcode bytes at 0x7f5dff78ebbf.
RSP: 002b:00007f5e005230e8 EFLAGS: 00000246 ORIG_RAX: 00000000000000ca
RAX: fffffffffffffe00 RBX: 00007f5dff9c5fa8 RCX: 00007f5dff78ebe9
RDX: 0000000000000000 RSI: 0000000000000080 RDI: 00007f5dff9c5fa8
RBP: 00007f5dff9c5fa0 R08: 0000000000000000 R09: 0000000000000000
R10: 0000000000000000 R11: 0000000000000246 R12: 0000000000000000
R13: 00007f5dff9c6038 R14: 00007ffcd55dc420 R15: 00007ffcd55dc508
 </TASK>


---
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