Re: [syzbot] [btrfs?] memory leak in btrfs_ref_tree_mod

[syzbot]

Hello,

syzbot has tested the proposed patch but the reproducer is still triggering an issue:
BUG: corrupted list in btrfs_ref_tree_mod

list_add corruption. prev->next should be next (ffff888122a51108), but was 0000000000058000. (prev=ffff88810e236d50).
------------[ cut here ]------------
kernel BUG at lib/list_debug.c:30!
invalid opcode: 0000 [#1] PREEMPT SMP
CPU: 0 PID: 45 Comm: kworker/u4:2 Not tainted 6.5.0-rc5-syzkaller-00182-g25aa0bebba72-dirty #0
Hardware name: Google Google Compute Engine/Google Compute Engine, BIOS Google 10/09/2023
Workqueue: btrfs-qgroup-rescan btrfs_work_helper
RIP: 0010:__list_add_valid+0x74/0x90 lib/list_debug.c:30
Code: e2 fe 0f 0b 48 89 c1 48 c7 c7 68 ff af 85 e8 a3 d7 e2 fe 0f 0b 48 89 d1 48 89 c6 4c 89 c2 48 c7 c7 c0 ff af 85 e8 8c d7 e2 fe <0f> 0b 48 89 f2 48 89 c1 48 89 fe 48 c7 c7 18 00 b0 85 e8 75 d7 e2
RSP: 0018:ffffc900001cf920 EFLAGS: 00010246
RAX: 0000000000000075 RBX: ffff88810e236d50 RCX: 0000000000000000
RDX: 0000000000000000 RSI: ffffffff8131cbd0 RDI: 0000000000000001
RBP: ffff888122a51108 R08: 0000000000000001 R09: 0000000000000000
R10: 0000000000000000 R11: 205d353454202020 R12: 0000000000000000
R13: ffff888122aec700 R14: ffff888122aec750 R15: ffff888122a510c0
FS:  0000000000000000(0000) GS:ffff88813bc00000(0000) knlGS:0000000000000000
CS:  0010 DS: 0000 ES: 0000 CR0: 0000000080050033
CR2: 00007fd2648f75e8 CR3: 000000010a57a000 CR4: 00000000003506f0
DR0: 0000000000000000 DR1: 0000000000000000 DR2: 0000000000000000
DR3: 0000000000000000 DR6: 00000000fffe0ff0 DR7: 0000000000000400
Call Trace:
 <TASK>
 __list_add include/linux/list.h:69 [inline]
 list_add_tail include/linux/list.h:102 [inline]
 btrfs_ref_tree_mod+0x454/0xbb0 fs/btrfs/ref-verify.c:887
 btrfs_free_tree_block+0x116/0x450 fs/btrfs/extent-tree.c:3250
 __btrfs_cow_block+0x6a5/0xa30 fs/btrfs/ctree.c:601
 btrfs_cow_block+0x154/0x2b0 fs/btrfs/ctree.c:712
 btrfs_search_slot+0xa49/0x1770 fs/btrfs/ctree.c:2194
 btrfs_update_root+0x6f/0x500 fs/btrfs/root-tree.c:137
 commit_fs_roots+0x236/0x360 fs/btrfs/transaction.c:1450
 btrfs_commit_transaction+0x93e/0x15c0 fs/btrfs/transaction.c:2393
 btrfs_qgroup_rescan_worker+0x389/0x610 fs/btrfs/qgroup.c:3417
 btrfs_work_helper+0x158/0x540 fs/btrfs/async-thread.c:314
 process_one_work+0x2f1/0x640 kernel/workqueue.c:2600
 worker_thread+0x5c/0x5c0 kernel/workqueue.c:2751
 kthread+0x12b/0x170 kernel/kthread.c:389
 ret_from_fork+0x2c/0x40 arch/x86/kernel/process.c:145
 ret_from_fork_asm+0x11/0x20 arch/x86/entry/entry_64.S:304
 </TASK>
Modules linked in:
---[ end trace 0000000000000000 ]---
RIP: 0010:__list_add_valid+0x74/0x90 lib/list_debug.c:30
Code: e2 fe 0f 0b 48 89 c1 48 c7 c7 68 ff af 85 e8 a3 d7 e2 fe 0f 0b 48 89 d1 48 89 c6 4c 89 c2 48 c7 c7 c0 ff af 85 e8 8c d7 e2 fe <0f> 0b 48 89 f2 48 89 c1 48 89 fe 48 c7 c7 18 00 b0 85 e8 75 d7 e2
RSP: 0018:ffffc900001cf920 EFLAGS: 00010246

RAX: 0000000000000075 RBX: ffff88810e236d50 RCX: 0000000000000000
RDX: 0000000000000000 RSI: ffffffff8131cbd0 RDI: 0000000000000001
RBP: ffff888122a51108 R08: 0000000000000001 R09: 0000000000000000
R10: 0000000000000000 R11: 205d353454202020 R12: 0000000000000000
R13: ffff888122aec700 R14: ffff888122aec750 R15: ffff888122a510c0
FS:  0000000000000000(0000) GS:ffff88813bc00000(0000) knlGS:0000000000000000
CS:  0010 DS: 0000 ES: 0000 CR0: 0000000080050033
CR2: 00007fd2648f75e8 CR3: 000000010a57a000 CR4: 00000000003506f0
DR0: 0000000000000000 DR1: 0000000000000000 DR2: 0000000000000000
DR3: 0000000000000000 DR6: 00000000fffe0ff0 DR7: 0000000000000400


Tested on:

commit:         25aa0beb Merge tag 'net-6.5-rc6' of git://git.kernel.o..
git tree:       git://git.kernel.org/pub/scm/linux/kernel/git/next/linux-next.git
console output: https://syzkaller.appspot.com/x/log.txt?x=10deb938e80000
kernel config:  https://syzkaller.appspot.com/x/.config?x=2bf8962e4f7984f4
dashboard link: https://syzkaller.appspot.com/bug?extid=d66de4cbf532749df35f
compiler:       gcc (Debian 12.2.0-14) 12.2.0, GNU ld (GNU Binutils for Debian) 2.40
patch:          https://syzkaller.appspot.com/x/patch.diff?x=16a72ca7680000