* [PATCH v2] kexec: Make a pair of map and unmap reserved pages when kdump fails to start
@ 2015-06-30 5:44 Minfei Huang
2015-07-01 14:40 ` Michael Holzheu
0 siblings, 1 reply; 3+ messages in thread
From: Minfei Huang @ 2015-06-30 5:44 UTC (permalink / raw)
To: ebiederm, vgoyal, schwidefsky, heiko.carstens, linux390, holzheu
Cc: linux-s390, kexec, linux-kernel, Minfei Huang
For some arch, kexec shall map the reserved pages, then use them, when
we try to start the kdump service.
Now kexec will never unmap the reserved pages, once it fails to continue
starting the kdump service.
Make a pair of reserved pages in kdump starting path, whatever kexec
fails or not.
Signed-off-by: Minfei Huang <mnfhuang@gmail.com>
---
kernel/kexec.c | 26 ++++++++++++++------------
1 file changed, 14 insertions(+), 12 deletions(-)
diff --git a/kernel/kexec.c b/kernel/kexec.c
index 4589899..68f6dfb 100644
--- a/kernel/kexec.c
+++ b/kernel/kexec.c
@@ -1291,35 +1291,37 @@ SYSCALL_DEFINE4(kexec_load, unsigned long, entry, unsigned long, nr_segments,
*/
kimage_free(xchg(&kexec_crash_image, NULL));
- result = kimage_alloc_init(&image, entry, nr_segments,
- segments, flags);
- crash_map_reserved_pages();
- } else {
- /* Loading another kernel to reboot into. */
-
- result = kimage_alloc_init(&image, entry, nr_segments,
- segments, flags);
}
+
+ result = kimage_alloc_init(&image, entry, nr_segments,
+ segments, flags);
if (result)
goto out;
+ 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 out;
+ goto failure;
for (i = 0; i < nr_segments; i++) {
result = kimage_load_segment(image, &image->segment[i]);
if (result)
- goto out;
+ goto failure;
}
kimage_terminate(image);
+
+failure:
if (flags & KEXEC_ON_CRASH)
crash_unmap_reserved_pages();
}
- /* Install the new kernel, and Uninstall the old */
- image = xchg(dest_image, image);
+
+ if (result == 0)
+ /* Install the new kernel, and Uninstall the old */
+ image = xchg(dest_image, image);
out:
mutex_unlock(&kexec_mutex);
--
2.2.2
^ permalink raw reply related [flat|nested] 3+ messages in thread* Re: [PATCH v2] kexec: Make a pair of map and unmap reserved pages when kdump fails to start
2015-06-30 5:44 [PATCH v2] kexec: Make a pair of map and unmap reserved pages when kdump fails to start Minfei Huang
@ 2015-07-01 14:40 ` Michael Holzheu
2015-07-01 15:06 ` Minfei Huang
0 siblings, 1 reply; 3+ messages in thread
From: Michael Holzheu @ 2015-07-01 14:40 UTC (permalink / raw)
To: Minfei Huang
Cc: ebiederm, vgoyal, schwidefsky, heiko.carstens, linux390,
linux-s390, kexec, linux-kernel
Hello Minfei,
Regarding functionality your patch looks ok for me.
But the code is not easy to read.
What about replacing the "failure" label with "fail_unmap_pages"?
Michael
On Tue, 30 Jun 2015 13:44:46 +0800
Minfei Huang <mnfhuang@gmail.com> wrote:
> For some arch, kexec shall map the reserved pages, then use them, when
> we try to start the kdump service.
>
> Now kexec will never unmap the reserved pages, once it fails to continue
> starting the kdump service.
>
> Make a pair of reserved pages in kdump starting path, whatever kexec
> fails or not.
>
> Signed-off-by: Minfei Huang <mnfhuang@gmail.com>
> ---
> kernel/kexec.c | 26 ++++++++++++++------------
> 1 file changed, 14 insertions(+), 12 deletions(-)
>
> diff --git a/kernel/kexec.c b/kernel/kexec.c
> index 4589899..68f6dfb 100644
> --- a/kernel/kexec.c
> +++ b/kernel/kexec.c
> @@ -1291,35 +1291,37 @@ SYSCALL_DEFINE4(kexec_load, unsigned long, entry, unsigned long, nr_segments,
> */
>
> kimage_free(xchg(&kexec_crash_image, NULL));
> - result = kimage_alloc_init(&image, entry, nr_segments,
> - segments, flags);
> - crash_map_reserved_pages();
> - } else {
> - /* Loading another kernel to reboot into. */
> -
> - result = kimage_alloc_init(&image, entry, nr_segments,
> - segments, flags);
> }
> +
> + result = kimage_alloc_init(&image, entry, nr_segments,
> + segments, flags);
> if (result)
> goto out;
>
> + 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 out;
> + goto failure;
>
> for (i = 0; i < nr_segments; i++) {
> result = kimage_load_segment(image, &image->segment[i]);
> if (result)
> - goto out;
> + goto failure;
> }
> kimage_terminate(image);
> +
> +failure:
> if (flags & KEXEC_ON_CRASH)
> crash_unmap_reserved_pages();
> }
> - /* Install the new kernel, and Uninstall the old */
> - image = xchg(dest_image, image);
> +
> + if (result == 0)
> + /* Install the new kernel, and Uninstall the old */
> + image = xchg(dest_image, image);
>
> out:
> mutex_unlock(&kexec_mutex);
^ permalink raw reply [flat|nested] 3+ messages in thread* Re: [PATCH v2] kexec: Make a pair of map and unmap reserved pages when kdump fails to start
2015-07-01 14:40 ` Michael Holzheu
@ 2015-07-01 15:06 ` Minfei Huang
0 siblings, 0 replies; 3+ messages in thread
From: Minfei Huang @ 2015-07-01 15:06 UTC (permalink / raw)
To: Michael Holzheu
Cc: ebiederm, vgoyal, schwidefsky, heiko.carstens, linux390,
linux-s390, kexec, linux-kernel
On 07/01/15 at 04:40P, Michael Holzheu wrote:
> Hello Minfei,
>
> Regarding functionality your patch looks ok for me.
> But the code is not easy to read.
>
> What about replacing the "failure" label with "fail_unmap_pages"?
Sure. I will repost v3 to fix it.
Thanks
Minfei
>
> Michael
>
> On Tue, 30 Jun 2015 13:44:46 +0800
> Minfei Huang <mnfhuang@gmail.com> wrote:
>
> > For some arch, kexec shall map the reserved pages, then use them, when
> > we try to start the kdump service.
> >
> > Now kexec will never unmap the reserved pages, once it fails to continue
> > starting the kdump service.
> >
> > Make a pair of reserved pages in kdump starting path, whatever kexec
> > fails or not.
> >
> > Signed-off-by: Minfei Huang <mnfhuang@gmail.com>
> > ---
> > kernel/kexec.c | 26 ++++++++++++++------------
> > 1 file changed, 14 insertions(+), 12 deletions(-)
> >
> > diff --git a/kernel/kexec.c b/kernel/kexec.c
> > index 4589899..68f6dfb 100644
> > --- a/kernel/kexec.c
> > +++ b/kernel/kexec.c
> > @@ -1291,35 +1291,37 @@ SYSCALL_DEFINE4(kexec_load, unsigned long, entry, unsigned long, nr_segments,
> > */
> >
> > kimage_free(xchg(&kexec_crash_image, NULL));
> > - result = kimage_alloc_init(&image, entry, nr_segments,
> > - segments, flags);
> > - crash_map_reserved_pages();
> > - } else {
> > - /* Loading another kernel to reboot into. */
> > -
> > - result = kimage_alloc_init(&image, entry, nr_segments,
> > - segments, flags);
> > }
> > +
> > + result = kimage_alloc_init(&image, entry, nr_segments,
> > + segments, flags);
> > if (result)
> > goto out;
> >
> > + 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 out;
> > + goto failure;
> >
> > for (i = 0; i < nr_segments; i++) {
> > result = kimage_load_segment(image, &image->segment[i]);
> > if (result)
> > - goto out;
> > + goto failure;
> > }
> > kimage_terminate(image);
> > +
> > +failure:
> > if (flags & KEXEC_ON_CRASH)
> > crash_unmap_reserved_pages();
> > }
> > - /* Install the new kernel, and Uninstall the old */
> > - image = xchg(dest_image, image);
> > +
> > + if (result == 0)
> > + /* Install the new kernel, and Uninstall the old */
> > + image = xchg(dest_image, image);
> >
> > out:
> > mutex_unlock(&kexec_mutex);
>
^ permalink raw reply [flat|nested] 3+ messages in thread
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2015-06-30 5:44 [PATCH v2] kexec: Make a pair of map and unmap reserved pages when kdump fails to start Minfei Huang
2015-07-01 14:40 ` Michael Holzheu
2015-07-01 15:06 ` Minfei Huang
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