[syzbot] [btrfs?] kernel BUG in btrfs_free_fs_info

[syzbot]

Hello,

syzbot found the following issue on:

HEAD commit: 56fb6f92854f Merge tag 'drm-next-2024-05-25' of https://gi..
git tree: upstream
console output: https://syzkaller.appspot.com/x/log.txt?x=15874672980000
kernel config: https://syzkaller.appspot.com/x/.config?x=2b8d1faad9ceb620
dashboard link: https://syzkaller.appspot.com/bug?extid=2f3cc5860d147a83eb3d
compiler: gcc (Debian 12.2.0-14) 12.2.0, GNU ld (GNU Binutils for Debian) 2.40
userspace arch: i386

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

Downloadable assets:
disk image (non-bootable): https://storage.googleapis.com/syzbot-assets/7bc7510fe41f/non_bootable_disk-56fb6f92.raw.xz
vmlinux: https://storage.googleapis.com/syzbot-assets/65ffe3ca9bb3/vmlinux-56fb6f92.xz
kernel image: https://storage.googleapis.com/syzbot-assets/354ef77a71b6/bzImage-56fb6f92.xz

IMPORTANT: if you fix the issue, please add the following tag to the commit:
Reported-by: syzbot+2f3cc5...@syzkaller.appspotmail.com

assertion failed: percpu_counter_sum_positive(em_counter) == 0, in fs/btrfs/disk-io.c:1274
------------[ cut here ]------------
kernel BUG at fs/btrfs/disk-io.c:1274!
Oops: invalid opcode: 0000 [#1] PREEMPT SMP KASAN NOPTI
CPU: 0 PID: 5236 Comm: syz-executor.3 Not tainted 6.9.0-syzkaller-12277-g56fb6f92854f #0
Hardware name: QEMU Standard PC (Q35 + ICH9, 2009), BIOS 1.16.2-debian-1.16.2-1 04/01/2014
RIP: 0010:btrfs_free_fs_info+0x3c6/0x470 fs/btrfs/disk-io.c:1274
Code: e9 df 19 42 fe e8 0a b0 03 fe b9 fa 04 00 00 48 c7 c2 80 99 76 8b 48 c7 c6 20 ab 76 8b 48 c7 c7 00 9a 76 8b e8 fb 4d e4 fd 90 <0f> 0b e8 23 e2 60 fe e9 60 fd ff ff e8 19 e2 60 fe e9 02 fd ff ff
RSP: 0018:ffffc90002bdfda8 EFLAGS: 00010286
RAX: 000000000000005a RBX: 0000000000000001 RCX: ffffffff816f3159
RDX: 0000000000000000 RSI: ffffffff816fbd56 RDI: 0000000000000005
RBP: ffff88805a888000 R08: 0000000000000005 R09: 0000000000000000
R10: 0000000080000000 R11: 0000000000000000 R12: ffff88805a8890f0
R13: ffff888057ba1a40 R14: ffffed1003fcaa3d R15: ffff888057ba1a80
FS: 0000000000000000(0000) GS:ffff88802c000000(0063) knlGS:0000000057e98400
CS: 0010 DS: 002b ES: 002b CR0: 0000000080050033
CR2: 00000000f7384414 CR3: 0000000057b96000 CR4: 0000000000350ef0
DR0: 0000000000000000 DR1: 0000000000000000 DR2: 0000000000000000
DR3: 0000000000000000 DR6: 00000000fffe0ff0 DR7: 0000000000000400
Call Trace:
<TASK>
deactivate_locked_super+0xbe/0x1a0 fs/super.c:473
deactivate_super+0xde/0x100 fs/super.c:506
cleanup_mnt+0x222/0x450 fs/namespace.c:1267
task_work_run+0x14e/0x250 kernel/task_work.c:180
resume_user_mode_work include/linux/resume_user_mode.h:50 [inline]
exit_to_user_mode_loop kernel/entry/common.c:114 [inline]
exit_to_user_mode_prepare include/linux/entry-common.h:328 [inline]
__syscall_exit_to_user_mode_work kernel/entry/common.c:207 [inline]
syscall_exit_to_user_mode+0x278/0x2a0 kernel/entry/common.c:218
__do_fast_syscall_32+0x80/0x120 arch/x86/entry/common.c:389
do_fast_syscall_32+0x32/0x80 arch/x86/entry/common.c:411
entry_SYSENTER_compat_after_hwframe+0x84/0x8e
RIP: 0023:0xf731f579
Code: b8 01 10 06 03 74 b4 01 10 07 03 74 b0 01 10 08 03 74 d8 01 00 00 00 00 00 00 00 00 00 00 00 00 00 51 52 55 89 e5 0f 34 cd 80 <5d> 5a 59 c3 90 90 90 90 8d b4 26 00 00 00 00 8d b4 26 00 00 00 00
RSP: 002b:00000000ff9328c8 EFLAGS: 00000292 ORIG_RAX: 0000000000000034
RAX: 0000000000000000 RBX: 00000000ff932970 RCX: 0000000000000009
RDX: 00000000f7475ff4 RSI: 00000000f73c6361 RDI: 00000000ff933a14
RBP: 00000000ff932970 R08: 0000000000000000 R09: 0000000000000000
R10: 0000000000000000 R11: 0000000000000296 R12: 0000000000000000
R13: 0000000000000000 R14: 0000000000000000 R15: 0000000000000000
</TASK>
Modules linked in:
---[ end trace 0000000000000000 ]---
RIP: 0010:btrfs_free_fs_info+0x3c6/0x470 fs/btrfs/disk-io.c:1274
Code: e9 df 19 42 fe e8 0a b0 03 fe b9 fa 04 00 00 48 c7 c2 80 99 76 8b 48 c7 c6 20 ab 76 8b 48 c7 c7 00 9a 76 8b e8 fb 4d e4 fd 90 <0f> 0b e8 23 e2 60 fe e9 60 fd ff ff e8 19 e2 60 fe e9 02 fd ff ff
RSP: 0018:ffffc90002bdfda8 EFLAGS: 00010286
RAX: 000000000000005a RBX: 0000000000000001 RCX: ffffffff816f3159
RDX: 0000000000000000 RSI: ffffffff816fbd56 RDI: 0000000000000005
RBP: ffff88805a888000 R08: 0000000000000005 R09: 0000000000000000
R10: 0000000080000000 R11: 0000000000000000 R12: ffff88805a8890f0
R13: ffff888057ba1a40 R14: ffffed1003fcaa3d R15: ffff888057ba1a80
FS: 0000000000000000(0000) GS:ffff88802c100000(0063) knlGS:0000000057e98400
CS: 0010 DS: 002b ES: 002b CR0: 0000000080050033
CR2: 000055bc24d74268 CR3: 0000000057b96000 CR4: 0000000000350ef0
DR0: 0000000000000000 DR1: 0000000000000000 DR2: 0000000000000000
DR3: 0000000000000000 DR6: 00000000fffe0ff0 DR7: 0000000000000400
----------------
Code disassembly (best guess), 2 bytes skipped:
0: 10 06 adc %al,(%rsi)
2: 03 74 b4 01 add 0x1(%rsp,%rsi,4),%esi
6: 10 07 adc %al,(%rdi)
8: 03 74 b0 01 add 0x1(%rax,%rsi,4),%esi
c: 10 08 adc %cl,(%rax)
e: 03 74 d8 01 add 0x1(%rax,%rbx,8),%esi
1e: 00 51 52 add %dl,0x52(%rcx)
21: 55 push %rbp
22: 89 e5 mov %esp,%ebp
24: 0f 34 sysenter
26: cd 80 int $0x80
* 28: 5d pop %rbp <-- trapping instruction
29: 5a pop %rdx
2a: 59 pop %rcx
2b: c3 ret
2c: 90 nop
2d: 90 nop
2e: 90 nop
2f: 90 nop
30: 8d b4 26 00 00 00 00 lea 0x0(%rsi,%riz,1),%esi
37: 8d b4 26 00 00 00 00 lea 0x0(%rsi,%riz,1),%esi


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