linux-kernel - [RFC v2 20/43] PKRAM: disable feature when running the kdump kernel

lists.openwall.net		lists / announce owl-users owl-dev john-users john-dev passwdqc-users yescrypt popa3d-users / oss-security kernel-hardening musl sabotage tlsify passwords / crypt-dev xvendor / Bugtraq Full-Disclosure linux-kernel linux-netdev linux-ext4 linux-hardening linux-cve-announce PHC
Open Source and information security mailing list archives

Hash Suite: Windows password security audit tool. GUI, reports in PDF.

[<prev] [next>] [<thread-prev] [thread-next>] [day] [month] [year] [list]

Message-Id: <1617140178-8773-21-git-send-email-anthony.yznaga@oracle.com>
Date:   Tue, 30 Mar 2021 14:35:55 -0700
From:   Anthony Yznaga <anthony.yznaga@...cle.com>
To:     linux-mm@...ck.org, linux-kernel@...r.kernel.org
Cc:     willy@...radead.org, corbet@....net, tglx@...utronix.de,
        mingo@...hat.com, bp@...en8.de, x86@...nel.org, hpa@...or.com,
        dave.hansen@...ux.intel.com, luto@...nel.org, peterz@...radead.org,
        rppt@...nel.org, akpm@...ux-foundation.org, hughd@...gle.com,
        ebiederm@...ssion.com, keescook@...omium.org, ardb@...nel.org,
        nivedita@...m.mit.edu, jroedel@...e.de, masahiroy@...nel.org,
        nathan@...nel.org, terrelln@...com, vincenzo.frascino@....com,
        martin.b.radev@...il.com, andreyknvl@...gle.com,
        daniel.kiper@...cle.com, rafael.j.wysocki@...el.com,
        dan.j.williams@...el.com, Jonathan.Cameron@...wei.com,
        bhe@...hat.com, rminnich@...il.com, ashish.kalra@....com,
        guro@...com, hannes@...xchg.org, mhocko@...nel.org,
        iamjoonsoo.kim@....com, vbabka@...e.cz, alex.shi@...ux.alibaba.com,
        david@...hat.com, richard.weiyang@...il.com,
        vdavydov.dev@...il.com, graf@...zon.com, jason.zeng@...el.com,
        lei.l.li@...el.com, daniel.m.jordan@...cle.com,
        steven.sistare@...cle.com, linux-fsdevel@...r.kernel.org,
        linux-doc@...r.kernel.org, kexec@...ts.infradead.org
Subject: [RFC v2 20/43] PKRAM: disable feature when running the kdump kernel

The kdump kernel should not preserve or restore pages.

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

diff --git a/mm/pkram.c b/mm/pkram.c
index 8700fd77dc67..aea069cc49be 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>
@@ -189,7 +190,7 @@ 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");
@@ -286,6 +287,9 @@ 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;
@@ -1315,7 +1319,7 @@ 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);
-- 
1.8.3.1