[syzbot] [bcachefs?] kernel panic: bch_dev->ref underflow, last put: bch2_get_next_dev

[syzbot <syzbot+a96175a4ea467a49c546@syzkaller.appspotmail.com>]

Hello,

syzbot found the following issue on:

HEAD commit:    75fa778d74b7 Add linux-next specific files for 20240510
git tree:       linux-next
console+strace: https://syzkaller.appspot.com/x/log.txt?x=1440d068980000
kernel config:  https://syzkaller.appspot.com/x/.config?x=ccdd3ebd6715749a
dashboard link: https://syzkaller.appspot.com/bug?extid=a96175a4ea467a49c546
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=128cd23f180000
C reproducer:   https://syzkaller.appspot.com/x/repro.c?x=15244970980000

Downloadable assets:
disk image: https://storage.googleapis.com/syzbot-assets/ad9391835bcf/disk-75fa778d.raw.xz
vmlinux: https://storage.googleapis.com/syzbot-assets/d827b3da9a26/vmlinux-75fa778d.xz
kernel image: https://storage.googleapis.com/syzbot-assets/8f32f0182388/bzImage-75fa778d.xz
mounted in repro: https://storage.googleapis.com/syzbot-assets/6a0d89f813ac/mount_0.gz

The issue was bisected to:

commit 552aa5486579c18b4f8e7ca03ef88fa573c517b5
Author: Kent Overstreet <kent.overstreet@linux.dev>
Date:   Fri May 3 22:07:40 2024 +0000

    bcachefs: Debug asserts for ca->ref

bisection log:  https://syzkaller.appspot.com/x/bisect.txt?x=10d08b5c980000
final oops:     https://syzkaller.appspot.com/x/report.txt?x=12d08b5c980000
console output: https://syzkaller.appspot.com/x/log.txt?x=14d08b5c980000

IMPORTANT: if you fix the issue, please add the following tag to the commit:
Reported-by: syzbot+a96175a4ea467a49c546@syzkaller.appspotmail.com
Fixes: 552aa5486579 ("bcachefs: Debug asserts for ca->ref")

bucket 0:19 gen 51 different types of data in same bucket: (invalid data type), sb
while marking sb, shutting down
bcachefs (loop0): inconsistency detected - emergency read only at journal seq 10
bcachefs (loop0): bch2_trans_mark_dev_sb(): error EIO
Kernel panic - not syncing: bch_dev->ref underflow, last put: rcu_lock_acquire include/linux/rcupdate.h:329 [inline]
Kernel panic - not syncing: bch_dev->ref underflow, last put: rcu_read_lock include/linux/rcupdate.h:781 [inline]
Kernel panic - not syncing: bch_dev->ref underflow, last put: bch2_get_next_dev+0x26/0x500 fs/bcachefs/sb-members.h:126
CPU: 1 PID: 5098 Comm: syz-executor215 Not tainted 6.9.0-rc7-next-20240510-syzkaller #0
Hardware name: Google Google Compute Engine/Google Compute Engine, BIOS Google 04/02/2024
Call Trace:
 <TASK>
 __dump_stack lib/dump_stack.c:88 [inline]
 dump_stack_lvl+0x241/0x360 lib/dump_stack.c:114
 panic+0x349/0x860 kernel/panic.c:347
 __bch2_dev_put fs/bcachefs/sb-members.h:109 [inline]
 bch2_dev_put fs/bcachefs/sb-members.h:121 [inline]
 bch2_trans_mark_dev_sbs_flags+0xaa7/0xab0 fs/bcachefs/buckets.c:1467
 bch2_run_recovery_pass+0xf0/0x1e0 fs/bcachefs/recovery_passes.c:182
 bch2_run_recovery_passes+0x19e/0x820 fs/bcachefs/recovery_passes.c:225
 bch2_fs_recovery+0x2370/0x3700 fs/bcachefs/recovery.c:804
 bch2_fs_start+0x356/0x5b0 fs/bcachefs/super.c:1031
 bch2_fs_open+0xa8d/0xdf0 fs/bcachefs/super.c:2123
 bch2_mount+0x71d/0x1320 fs/bcachefs/fs.c:1917
 legacy_get_tree+0xee/0x190 fs/fs_context.c:662
 vfs_get_tree+0x90/0x2a0 fs/super.c:1780
 do_new_mount+0x2be/0xb40 fs/namespace.c:3352
 do_mount fs/namespace.c:3692 [inline]
 __do_sys_mount fs/namespace.c:3898 [inline]
 __se_sys_mount+0x2d9/0x3c0 fs/namespace.c:3875
 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: 0033:0x7f7f37cfa8ca
Code: d8 64 89 02 48 c7 c0 ff ff ff ff eb a6 e8 5e 04 00 00 66 2e 0f 1f 84 00 00 00 00 00 0f 1f 40 00 49 89 ca b8 a5 00 00 00 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:00007fff662e7d38 EFLAGS: 00000282 ORIG_RAX: 00000000000000a5
RAX: ffffffffffffffda RBX: 00007fff662e7d50 RCX: 00007f7f37cfa8ca
RDX: 0000000020011a00 RSI: 0000000020000200 RDI: 00007fff662e7d50
RBP: 0000000000000004 R08: 00007fff662e7d90 R09: 00000000000119eb
R10: 000000000120041c R11: 0000000000000282 R12: 000000000120041c
R13: 00007fff662e7d90 R14: 0000000000000003 R15: 0000000001000000
 </TASK>
Kernel Offset: disabled
Rebooting in 86400 seconds..


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