Re: [PATCH v1 1/4] [RFC] fs/trampfd: Implement the trampoline file descriptor API

Oleg Nesterov
2020-07-28T14:50:27Z

On 07/28, madvenka@linux.microsoft.com wrote:
>
> +bool is_trampfd_vma(struct vm_area_struct *vma)
> +{
> + struct file *file = vma->vm_file;
> +
> + if (!file)
> + return false;
> + return !strcmp(file->f_path.dentry->d_name.name, trampfd_name);

Hmm, this looks obviously wrong or I am totally confused. A user can
create a file named "[trampfd]", mmap it, and fool trampfd_fault() ?

Why not

return file->f_op == trampfd_fops;

?

> +EXPORT_SYMBOL_GPL(is_trampfd_vma);

why is it exported?

Oleg.