On Fri, Jul 10, 2015 at 11:14:06AM +0200, Michael Holzheu wrote:
[..]
> What about the following patch:
> ---
> diff --git a/kernel/kexec.c b/kernel/kexec.c
> index 7a36fdc..7837c4e 100644
> --- a/kernel/kexec.c
> +++ b/kernel/kexec.c
> @@ -1236,10 +1236,68 @@ int kexec_load_disabled;
>
> static DEFINE_MUTEX(kexec_mutex);
>
> +static int __kexec_load(unsigned long entry, unsigned long nr_segments,
How about renaming the function to do_kexec_load()?
We also need to cleanup the description of commit. One needs to explain
problem better and what's the solution this patch is implemeting.
> + struct kexec_segment __user *segments,
> + unsigned long flags)
> +{
> + struct kimage **dest_image, *image;
> + unsigned long i;
> + int result;
> +
> + if (flags & KEXEC_ON_CRASH)
> + dest_image = &kexec_crash_image;
> + else
> + dest_image = &kexec_image;
> +
> + if (nr_segments == 0) {
> + /* Uninstall image */
> + kfree(xchg(dest_image, NULL));
kimage_free(), as you have already noted in a follow up mail.
> + return 0;
> + }
> + if (flags & KEXEC_ON_CRASH) {
> + /*
> + * Loading another kernel to switch to if this one
> + * crashes. Free any current crash dump kernel before
> + * we corrupt it.
> + */
> + kimage_free(xchg(&kexec_crash_image, NULL));
> + }
> +
> + result = kimage_alloc_init(&image, entry, nr_segments, segments, flags);
> + if (result)
> + return result;
> +
> + if (flags & KEXEC_ON_CRASH)
> + crash_map_reserved_pages();
> +
> + if (flags & KEXEC_PRESERVE_CONTEXT)
> + image->preserve_context = 1;
> +
> + result = machine_kexec_prepare(image);
> + if (result)
> + goto failure_unmap_mem;
> +
> + for (i = 0; i < nr_segments; i++) {
> + result = kimage_load_segment(image, &image->segment[i]);
> + if (result)
> + goto failure_unmap_mem;
> + }
> +
> + kimage_terminate(image);
> +
> + /* Install the new kernel and uninstall the old */
> + image = xchg(dest_image, image);
> +
> +failure_unmap_mem:
I don't like this tag "failure_unmap_mem". We are calling this both
in success path as well as failure path. So why not simply call it "out".
> + if (flags & KEXEC_ON_CRASH)
> + crash_unmap_reserved_pages();
> + kimage_free(image);
Now kimage_free() is called with kexec_mutex held. Previously that was
not the case. I hope that's not a problem.
> + return result;
> +}
> +
Thanks
Vivek
