On 07/09/15 at 05:54P, Michael Holzheu wrote:
> On Tue, 7 Jul 2015 17:18:40 -0400
> Vivek Goyal <vgo...@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, and will crash in here, since we do not
assign the image to NULL when we release the image above.
Thanks
Minfei
> return result;
> }
>
> SYSCALL_DEFINE4(kexec_load, unsigned long, entry, unsigned long, nr_segments,
> struct kexec_segment __user *, segments, unsigned long, flags)
> {
> - struct kimage **dest_image, *image;
> int result;
>
> /* We only trust the superuser with rebooting the system. */
> @@ -1315,9 +1317,6 @@ SYSCALL_DEFINE4(kexec_load, unsigned lon
> if (nr_segments > KEXEC_SEGMENT_MAX)
> return -EINVAL;
>
> - image = NULL;
> - result = 0;
> -
> /* Because we write directly to the reserved memory
> * region when loading crash kernels we need a mutex here to
> * prevent multiple crash kernels from attempting to load
> @@ -1329,24 +1328,9 @@ SYSCALL_DEFINE4(kexec_load, unsigned lon
> if (!mutex_trylock(&kexec_mutex))
> return -EBUSY;
>
> - dest_image = &kexec_image;
> - if (flags & KEXEC_ON_CRASH)
> - dest_image = &kexec_crash_image;
> -
> /* Load new kernel */
> - if (nr_segments > 0) {
> - result = __kexec_load(&image, entry, nr_segments, segments,
> - flags);
> - if (result)
> - goto out;
> - }
> -
> - /* Install the new kernel, and Uninstall the old */
> - image = xchg(dest_image, image);
> -
> -out:
> + result = __kexec_load(entry, nr_segments, segments, flags);
> mutex_unlock(&kexec_mutex);
> - kimage_free(image);
>
> return result;
> }
>
--
To unsubscribe from this list: send the line "unsubscribe linux-kernel" in
the body of a message to majord...@vger.kernel.org
More majordomo info at http://vger.kernel.org/majordomo-info.html
Please read the FAQ at http://www.tux.org/lkml/
