[RFC 20/43] PKRAM: disable feature when running the kdump kernel

From: Anthony Yznaga
Date: Wed May 06 2020 - 20:44:50 EST


The kdump kernel should not preserve or restore pages.

Signed-off-by: Anthony Yznaga <anthony.yznaga@xxxxxxxxxx>
---
mm/pkram.c | 8 ++++++--
1 file changed, 6 insertions(+), 2 deletions(-)

diff --git a/mm/pkram.c b/mm/pkram.c
index 95e691382721..4d4d836fea53 100644
--- a/mm/pkram.c
+++ b/mm/pkram.c
@@ -1,4 +1,5 @@
// SPDX-License-Identifier: GPL-2.0
+#include <linux/crash_dump.h>
#include <linux/err.h>
#include <linux/gfp.h>
#include <linux/highmem.h>
@@ -193,7 +194,7 @@ void __init pkram_reserve(void)
{
int err = 0;

- if (!pkram_sb_pfn)
+ if (!pkram_sb_pfn || is_kdump_kernel())
return;

pr_info("PKRAM: Examining preserved memory...\n");
@@ -305,6 +306,9 @@ static void pkram_show_banned(void)
int i;
unsigned long n, total = 0;

+ if (is_kdump_kernel())
+ return;
+
pr_info("PKRAM: banned regions:\n");
for (i = 0; i < nr_banned; i++) {
n = banned[i].end - banned[i].start + 1;
@@ -1223,7 +1227,7 @@ static int __init pkram_init_sb(void)

static int __init pkram_init(void)
{
- if (pkram_init_sb()) {
+ if (!is_kdump_kernel() && pkram_init_sb()) {
register_reboot_notifier(&pkram_reboot_notifier);
register_shrinker(&banned_pages_shrinker);
sysfs_update_group(kernel_kobj, &pkram_attr_group);
--
2.13.3