[LU-8372] Suspicious dereference of pointer 'vma->vm_file' in ll_vm_{open|close}

• Type: Bug
• Resolution: Fixed
• Priority: Minor
• Fix Version/s: Lustre 2.9.0
• Labels: kw
• Severity: 3
• Assignee: Dmitry Eremin (Inactive)
• Reporter: Dmitry Eremin (Inactive)

Description

static void ll_vm_open(struct vm_area_struct * vma)
{
            struct inode *inode    = file_inode(vma->vm_file); <== 'vma->vm_file' is dereferenced by being passed as argument 1 to function 'file_inode'.
            struct vvp_object *vob = cl_inode2vvp(inode);

            ENTRY;
            LASSERT(vma->vm_file); <== 'vma->vm_file' is checked for NULL.
            LASSERT(atomic_read(&vob->vob_mmap_cnt) >= 0);
            atomic_inc(&vob->vob_mmap_cnt);
            EXIT;
}

So, LASSERT(vma->vm_file) is useless because if it's NULL it will crash in file_inode(vma->vm_file).