On Fri, Nov 22, 2019 at 07:18:28PM -0800, Alexei Starovoitov wrote:
> > + /* After filter unmountable pseudo filesytem, d_path won't call
> > + * dentry->d_op->d_name(), the normally path doesn't have any
> > + * sleepable code, and despite it uses the current macro to get
> > + * fs_struct (current->fs), we've already ensured we're in user
> > + * context, so it's ok to be here.
> > + */
> > + p = d_path(&f->f_path, dst, size);
> > + if (IS_ERR(p)) {
> > + ret = PTR_ERR(p);
> > + fput(f);
> > + goto error;
> > + }
> > +
> > + ret = strlen(p);
> > + memmove(dst, p, ret);
> > + dst[ret++] = '\0';
> > + fput(f);
> > + return ret;
> > +
> > +error:
> > + memset(dst, '0', size);
> > + return ret;
> > +}
>
> Al,
>
> could you please review about code whether it's doing enough checks to be
> called safely from preempt_disabled region?
Depends. Which context is it running in? In particular, which
locks might be already held?
