I just installed systemtap. When I wanted to use stap -o to send the result into a file, I got an error: sudo stap -o a.out b.stp
semantic error: unable to find member 'mnt_parent' for struct vfsmount (alternatives: mnt_root mnt_sb mnt_flags): operator '->' at /usr/share/systemtap/tapset/dentry.stp:104:54
source: if (@cast(vfsmnt, "vfsmount")->mnt_parent == vfsmnt)
I am so confused with the language systemtap uses. Can any one help me?