Re: [syzbot] [btrfs?] kernel BUG in btrfs_free_fs_info (2)

[David Sterba <dsterba@suse.cz>]

On Fri, Feb 21, 2025 at 08:28:24AM -0800, syzbot wrote:
> Hello,
> 
> syzbot found the following issue on:
> 
> HEAD commit:    0ad2507d5d93 Linux 6.14-rc3
> git tree:       upstream
> console output: https://syzkaller.appspot.com/x/log.txt?x=179ae898580000
> kernel config:  https://syzkaller.appspot.com/x/.config?x=6cc40dfe827ffb85
> dashboard link: https://syzkaller.appspot.com/bug?extid=bbbdd6d6efbfc5174561
> compiler:       Debian clang version 15.0.6, GNU ld (GNU Binutils for Debian) 2.40
> 
> Unfortunately, I don't have any reproducer for this issue yet.
> 
> Downloadable assets:
> disk image: https://storage.googleapis.com/syzbot-assets/6bb4d4755dce/disk-0ad2507d.raw.xz
> vmlinux: https://storage.googleapis.com/syzbot-assets/57594e8f74d9/vmlinux-0ad2507d.xz
> kernel image: https://storage.googleapis.com/syzbot-assets/a4f2442a20b1/bzImage-0ad2507d.xz
> 
> IMPORTANT: if you fix the issue, please add the following tag to the commit:
> Reported-by: syzbot+bbbdd6d6efbfc5174561@syzkaller.appspotmail.com
> 
> assertion failed: percpu_counter_sum_positive(em_counter) == 0, in fs/btrfs/disk-io.c:1266
> ------------[ cut here ]------------
> kernel BUG at fs/btrfs/disk-io.c:1266!

void btrfs_free_fs_info(struct btrfs_fs_info *fs_info)
{
        struct percpu_counter *em_counter = &fs_info->evictable_extent_maps;

        percpu_counter_destroy(&fs_info->stats_read_blocks);
        percpu_counter_destroy(&fs_info->dirty_metadata_bytes);
        percpu_counter_destroy(&fs_info->delalloc_bytes);
        percpu_counter_destroy(&fs_info->ordered_bytes);
        if (percpu_counter_initialized(em_counter))
                ASSERT(percpu_counter_sum_positive(em_counter) == 0);