On Fri, 10 Jul 2015 12:05:27 +0800
Minfei Huang <mnfhuang at gmail.com> wrote:
> On 07/09/15 at 05:54P, Michael Holzheu wrote:
> > On Tue, 7 Jul 2015 17:18:40 -0400
> > Vivek Goyal <vgoyal at redhat.com> wrote:
> >
> > > On Thu, Jul 02, 2015 at 09:45:52AM +0800, Minfei Huang wrote:
> >
> > [snip]
> >
> > > I am thinking of moving kernel loading code in a separate function to
> > > make things little simpler. Right now it is confusing.
> > >
> > > Can you please test attached patch. I have only compile tested it. This
> > > is primarily doing what you are doing but in a separate function. It
> > > seems more readable now.
> >
> > The patch looks good to me. What about the following patch on top
> > to make things even more readable?
> > ---
> > kernel/kexec.c | 50 +++++++++++++++++---------------------------------
> > 1 file changed, 17 insertions(+), 33 deletions(-)
> >
> > --- a/kernel/kexec.c
> > +++ b/kernel/kexec.c
> > @@ -1236,14 +1236,18 @@ int kexec_load_disabled;
> >
> > static DEFINE_MUTEX(kexec_mutex);
> >
> > -static int __kexec_load(struct kimage **rimage, unsigned long entry,
> > - unsigned long nr_segments,
> > +static int __kexec_load(unsigned long entry, unsigned long nr_segments,
> > struct kexec_segment __user * segments,
> > unsigned long flags)
> > {
> > + struct kimage *image, **dest_image;
> > unsigned long i;
> > int result;
> > - struct kimage *image;
> > +
> > + dest_image = (flags & KEXEC_ON_CRASH) ? &kexec_crash_image : &kexec_image;
> > +
> > + if (nr_segments == 0)
> > + return 0;
>
> It is fine, if nr_segments is 0. So we should deal with this case like
> original kexec code.
>
> >
> > if (flags & KEXEC_ON_CRASH) {
> > /*
> > @@ -1251,7 +1255,6 @@ static int __kexec_load(struct kimage **
> > * crashes. Free any current crash dump kernel before
> > * we corrupt it.
> > */
> > -
> > kimage_free(xchg(&kexec_crash_image, NULL));
> > }
> >
> > @@ -1267,30 +1270,29 @@ static int __kexec_load(struct kimage **
> >
> > result = machine_kexec_prepare(image);
> > if (result)
> > - goto out;
> > + goto fail;
> >
> > for (i = 0; i < nr_segments; i++) {
> > result = kimage_load_segment(image, &image->segment[i]);
> > if (result)
> > - goto out;
> > + goto fail;
> > }
> > -
> > kimage_terminate(image);
> > - *rimage = image;
> > -out:
> > + /* Install the new kernel, and uninstall the old */
> > + kimage_free(xchg(dest_image, image));
> > if (flags & KEXEC_ON_CRASH)
> > crash_unmap_reserved_pages();
> > -
> > - /* Free image if there was an error */
> > - if (result)
> > - kimage_free(image);
> > + return 0;
> > +fail:
> > + if (flags & KEXEC_ON_CRASH)
> > + crash_unmap_reserved_pages();
> > + kimage_free(image);
>
> Kernel release image again
Again? This is only done in the error case.
> , and will crash in here, since we do not
> assign the image to NULL when we release the image above.
Good catch, I should have set image=NULL at the beginning of __kexec_load().
Michael
