[v6.1] WARNING in lookup_inline_extent_backref

[syzbot]

Hello,

syzbot found the following issue on:

HEAD commit: ca87e77a2ef8 Linux 6.1.34
git tree: linux-6.1.y
console output: https://syzkaller.appspot.com/x/log.txt?x=118c29cf280000
kernel config: https://syzkaller.appspot.com/x/.config?x=c188e92022a334b
dashboard link: https://syzkaller.appspot.com/bug?extid=1fb409aedaee6e2bf793
compiler: Debian clang version 15.0.7, GNU ld (GNU Binutils for Debian) 2.35.2

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

Downloadable assets:
disk image: https://storage.googleapis.com/syzbot-assets/f48d514c343c/disk-ca87e77a.raw.xz
vmlinux: https://storage.googleapis.com/syzbot-assets/563336f1f216/vmlinux-ca87e77a.xz
kernel image: https://storage.googleapis.com/syzbot-assets/2254afa3642b/bzImage-ca87e77a.xz

IMPORTANT: if you fix the issue, please add the following tag to the commit:
Reported-by: syzbot+1fb409...@syzkaller.appspotmail.com

------------[ cut here ]------------
WARNING: CPU: 0 PID: 4073 at fs/btrfs/extent-tree.c:865 lookup_inline_extent_backref+0x8b3/0x13e0
Modules linked in:
CPU: 0 PID: 4073 Comm: syz-executor.2 Not tainted 6.1.34-syzkaller #0
Hardware name: Google Google Compute Engine/Google Compute Engine, BIOS Google 05/27/2023
RIP: 0010:lookup_inline_extent_backref+0x8b3/0x13e0 fs/btrfs/extent-tree.c:865
Code: de e8 51 19 09 fe 49 39 df 0f 87 f0 0a 00 00 e8 63 17 09 fe eb 30 83 7d 28 00 4c 8b 6c 24 28 0f 84 92 04 00 00 e8 4d 17 09 fe <0f> 0b 41 bc fb ff ff ff e9 d3 05 00 00 e8 3b 17 09 fe e9 aa 05 00
RSP: 0018:ffffc9000a446ee0 EFLAGS: 00010287
RAX: ffffffff8380be03 RBX: 0000000000000000 RCX: 0000000000040000
RDX: ffffc90005fcd000 RSI: 0000000000009083 RDI: 0000000000009084
RBP: ffffc9000a447090 R08: ffffffff8380b96e R09: ffffc9000a446c40
R10: ffffffffffffffff R11: dffffc0000000001 R12: dffffc0000000000
R13: ffff888078256a50 R14: ffffc9000a447000 R15: ffff888077320000
FS: 00007f9ed0d5a700(0000) GS:ffff8880b9800000(0000) knlGS:0000000000000000
CS: 0010 DS: 0000 ES: 0000 CR0: 0000000080050033
CR2: 00007f6c6e8aad38 CR3: 0000000092660000 CR4: 00000000003506f0
DR0: 0000000000000000 DR1: 0000000000000000 DR2: 0000000000000000
DR3: 0000000000000000 DR6: 00000000fffe0ff0 DR7: 0000000000000400
Call Trace:
<TASK>
insert_inline_extent_backref+0xe2/0x250 fs/btrfs/extent-tree.c:1152
__btrfs_inc_extent_ref+0x11f/0x5f0 fs/btrfs/extent-tree.c:1455
btrfs_run_delayed_refs_for_head fs/btrfs/extent-tree.c:1948 [inline]
__btrfs_run_delayed_refs+0x11bf/0x41b0 fs/btrfs/extent-tree.c:2011
btrfs_run_delayed_refs+0x13c/0x480 fs/btrfs/extent-tree.c:2142
qgroup_account_snapshot fs/btrfs/transaction.c:1538 [inline]
create_pending_snapshot+0x11de/0x2d40 fs/btrfs/transaction.c:1800
create_pending_snapshots+0x195/0x1d0 fs/btrfs/transaction.c:1868
btrfs_commit_transaction+0x1497/0x37e0 fs/btrfs/transaction.c:2336
create_snapshot+0x4a5/0x7e0 fs/btrfs/ioctl.c:835
btrfs_mksubvol+0x62e/0x760 fs/btrfs/ioctl.c:985
btrfs_mksnapshot+0xb5/0xf0 fs/btrfs/ioctl.c:1031
__btrfs_ioctl_snap_create+0x338/0x450 fs/btrfs/ioctl.c:2186
btrfs_ioctl_snap_create+0x136/0x190 fs/btrfs/ioctl.c:2213
btrfs_ioctl+0x15c/0xc10
vfs_ioctl fs/ioctl.c:51 [inline]
__do_sys_ioctl fs/ioctl.c:870 [inline]
__se_sys_ioctl+0xf1/0x160 fs/ioctl.c:856
do_syscall_x64 arch/x86/entry/common.c:50 [inline]
do_syscall_64+0x3d/0xb0 arch/x86/entry/common.c:80
entry_SYSCALL_64_after_hwframe+0x63/0xcd
RIP: 0033:0x7f9ed008c389
Code: 28 00 00 00 75 05 48 83 c4 28 c3 e8 f1 19 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 b8 ff ff ff f7 d8 64 89 01 48
RSP: 002b:00007f9ed0d5a168 EFLAGS: 00000246 ORIG_RAX: 0000000000000010
RAX: ffffffffffffffda RBX: 00007f9ed01ac050 RCX: 00007f9ed008c389
RDX: 0000000020002180 RSI: 0000000050009401 RDI: 0000000000000007
RBP: 00007f9ed00d7493 R08: 0000000000000000 R09: 0000000000000000
R10: 0000000000000000 R11: 0000000000000246 R12: 0000000000000000
R13: 00007ffed63788ef R14: 00007f9ed0d5a300 R15: 0000000000022000
</TASK>


---
This report is generated by a bot. It may contain errors.
See https://goo.gl/tpsmEJ for more information about syzbot.
syzbot engineers can be reached at syzk...@googlegroups.com.

syzbot will keep track of this issue. See:
https://goo.gl/tpsmEJ#status for how to communicate with syzbot.

If the bug is already fixed, let syzbot know by replying with:
#syz fix: exact-commit-title

If you want to change bug's subsystems, reply with:
#syz set subsystems: new-subsystem
(See the list of subsystem names on the web dashboard)

If the bug is a duplicate of another bug, reply with:
#syz dup: exact-subject-of-another-report

If you want to undo deduplication, reply with:
#syz undup

[syzbot]

syzbot has found a reproducer for the following issue on:

HEAD commit: ca87e77a2ef8 Linux 6.1.34
git tree: linux-6.1.y

console output: https://syzkaller.appspot.com/x/log.txt?x=15fbc85b280000

kernel config: https://syzkaller.appspot.com/x/.config?x=c188e92022a334b
dashboard link: https://syzkaller.appspot.com/bug?extid=1fb409aedaee6e2bf793
compiler: Debian clang version 15.0.7, GNU ld (GNU Binutils for Debian) 2.35.2

syz repro: https://syzkaller.appspot.com/x/repro.syz?x=17bbbae3280000
C reproducer: https://syzkaller.appspot.com/x/repro.c?x=1792f6bb280000

Downloadable assets:
disk image: https://storage.googleapis.com/syzbot-assets/f48d514c343c/disk-ca87e77a.raw.xz
vmlinux: https://storage.googleapis.com/syzbot-assets/563336f1f216/vmlinux-ca87e77a.xz
kernel image: https://storage.googleapis.com/syzbot-assets/2254afa3642b/bzImage-ca87e77a.xz

mounted in repro: https://storage.googleapis.com/syzbot-assets/d708ca0ecb50/mount_0.gz

IMPORTANT: if you fix the issue, please add the following tag to the commit:
Reported-by: syzbot+1fb409...@syzkaller.appspotmail.com

------------[ cut here ]------------

WARNING: CPU: 0 PID: 3698 at fs/btrfs/extent-tree.c:865 lookup_inline_extent_backref+0x8b3/0x13e0
Modules linked in:
CPU: 0 PID: 3698 Comm: syz-executor283 Not tainted 6.1.34-syzkaller #0

Hardware name: Google Google Compute Engine/Google Compute Engine, BIOS Google 05/27/2023
RIP: 0010:lookup_inline_extent_backref+0x8b3/0x13e0 fs/btrfs/extent-tree.c:865
Code: de e8 51 19 09 fe 49 39 df 0f 87 f0 0a 00 00 e8 63 17 09 fe eb 30 83 7d 28 00 4c 8b 6c 24 28 0f 84 92 04 00 00 e8 4d 17 09 fe <0f> 0b 41 bc fb ff ff ff e9 d3 05 00 00 e8 3b 17 09 fe e9 aa 05 00

RSP: 0018:ffffc9000444eee0 EFLAGS: 00010293
RAX: ffffffff8380be03 RBX: 0000000000000000 RCX: ffff888013ae5940
RDX: 0000000000000000 RSI: 0000000000000000 RDI: 0000000000000000
RBP: ffffc9000444f090 R08: ffffffff8380b96e R09: ffffc9000444ec40

R10: ffffffffffffffff R11: dffffc0000000001 R12: dffffc0000000000

R13: ffff8880766a70b0 R14: ffffc9000444f000 R15: ffff888072ce6000
FS: 00007fdbb854b700(0000) GS:ffff8880b9800000(0000) knlGS:0000000000000000

CS: 0010 DS: 0000 ES: 0000 CR0: 0000000080050033

CR2: 0000000020003000 CR3: 000000001e767000 CR4: 00000000003506f0

DR0: 0000000000000000 DR1: 0000000000000000 DR2: 0000000000000000
DR3: 0000000000000000 DR6: 00000000fffe0ff0 DR7: 0000000000000400
Call Trace:
<TASK>
insert_inline_extent_backref+0xe2/0x250 fs/btrfs/extent-tree.c:1152
__btrfs_inc_extent_ref+0x11f/0x5f0 fs/btrfs/extent-tree.c:1455
btrfs_run_delayed_refs_for_head fs/btrfs/extent-tree.c:1948 [inline]
__btrfs_run_delayed_refs+0x11bf/0x41b0 fs/btrfs/extent-tree.c:2011

btrfs_run_delayed_refs+0x2f5/0x480 fs/btrfs/extent-tree.c:2142

qgroup_account_snapshot fs/btrfs/transaction.c:1538 [inline]
create_pending_snapshot+0x11de/0x2d40 fs/btrfs/transaction.c:1800
create_pending_snapshots+0x195/0x1d0 fs/btrfs/transaction.c:1868
btrfs_commit_transaction+0x1497/0x37e0 fs/btrfs/transaction.c:2336
create_snapshot+0x4a5/0x7e0 fs/btrfs/ioctl.c:835
btrfs_mksubvol+0x62e/0x760 fs/btrfs/ioctl.c:985
btrfs_mksnapshot+0xb5/0xf0 fs/btrfs/ioctl.c:1031
__btrfs_ioctl_snap_create+0x338/0x450 fs/btrfs/ioctl.c:2186
btrfs_ioctl_snap_create+0x136/0x190 fs/btrfs/ioctl.c:2213
btrfs_ioctl+0x15c/0xc10
vfs_ioctl fs/ioctl.c:51 [inline]
__do_sys_ioctl fs/ioctl.c:870 [inline]
__se_sys_ioctl+0xf1/0x160 fs/ioctl.c:856
do_syscall_x64 arch/x86/entry/common.c:50 [inline]
do_syscall_64+0x3d/0xb0 arch/x86/entry/common.c:80
entry_SYSCALL_64_after_hwframe+0x63/0xcd

RIP: 0033:0x7fdbbf9c0db9
Code: 28 00 00 00 75 05 48 83 c4 28 c3 e8 71 15 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 b8 ff ff ff f7 d8 64 89 01 48
RSP: 002b:00007fdbb854b2f8 EFLAGS: 00000246 ORIG_RAX: 0000000000000010
RAX: ffffffffffffffda RBX: 00007fdbbfa4b7f0 RCX: 00007fdbbf9c0db9

RDX: 0000000020002180 RSI: 0000000050009401 RDI: 0000000000000007

RBP: 00007fdbbfa1868c R08: 0000000000000000 R09: 0000000000000000
R10: 0000000020000000 R11: 0000000000000246 R12: 0030656c69662f2e
R13: 00007fdbbfa17690 R14: 2a63d28a7f685400 R15: 00007fdbbfa4b7f8
</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.

[syzbot]

syzbot suspects this issue was fixed by commit:

commit 56f762659a5e9fde8220a88e19fd5ec4b12eda6d
Author: Josef Bacik <jo...@toxicpanda.com>
Date: Fri Dec 15 15:01:44 2023 +0000

btrfs: do not allow non subvolume root targets for snapshot

bisection log: https://syzkaller.appspot.com/x/bisect.txt?x=166b3099e80000
start commit: ca87e77a2ef8 Linux 6.1.34
git tree: linux-6.1.y

kernel config: https://syzkaller.appspot.com/x/.config?x=c188e92022a334b
dashboard link: https://syzkaller.appspot.com/bug?extid=1fb409aedaee6e2bf793

syz repro: https://syzkaller.appspot.com/x/repro.syz?x=17bbbae3280000
C reproducer: https://syzkaller.appspot.com/x/repro.c?x=1792f6bb280000

If the result looks correct, please mark the issue as fixed by replying with:

#syz fix: btrfs: do not allow non subvolume root targets for snapshot

For information about bisection process see: https://goo.gl/tpsmEJ#bisection