linux-kernel - [PATCH] mm: migrate: fix an incorrect call of prep_transhuge

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-next>] [day] [month] [year] [list]

Message-Id: <20171121021855.50525-1-zi.yan@sent.com>
Date:   Mon, 20 Nov 2017 21:18:55 -0500
From:   Zi Yan <zi.yan@...t.com>
To:     Andrew Morton <akpm@...ux-foundation.org>, linux-mm@...ck.org,
        linux-kernel@...r.kernel.org
Cc:     Zi Yan <zi.yan@...rutgers.edu>,
        Andrea Reale <ar@...ux.vnet.ibm.com>,
        Naoya Horiguchi <n-horiguchi@...jp.nec.com>,
        Jérôme Glisse <jglisse@...hat.com>,
        stable@...r.kernel.org
Subject: [PATCH] mm: migrate: fix an incorrect call of prep_transhuge_page()

From: Zi Yan <zi.yan@...rutgers.edu>

In [1], Andrea reported that during memory hotplug/hot remove
prep_transhuge_page() is called incorrectly on non-THP pages for
migration, when THP is on but THP migration is not enabled.
This leads to a bad state of target pages for migration.

This patch fixes it by only calling prep_transhuge_page() when we are
certain that the target page is THP.

[1] https://lkml.org/lkml/2017/11/20/411

Cc: stable@...r.kernel.org # v4.14
Fixes: 8135d8926c08 ("mm: memory_hotplug: memory hotremove supports thp migration")
Reported-by: Andrea Reale <ar@...ux.vnet.ibm.com>
Signed-off-by: Zi Yan <zi.yan@...rutgers.edu>
Cc: Naoya Horiguchi <n-horiguchi@...jp.nec.com>
Cc: "Jérôme Glisse" <jglisse@...hat.com>
---
 include/linux/migrate.h | 2 +-
 1 file changed, 1 insertion(+), 1 deletion(-)

diff --git a/include/linux/migrate.h b/include/linux/migrate.h
index 895ec0c4942e..a2246cf670ba 100644
--- a/include/linux/migrate.h
+++ b/include/linux/migrate.h
@@ -54,7 +54,7 @@ static inline struct page *new_page_nodemask(struct page *page,
 	new_page = __alloc_pages_nodemask(gfp_mask, order,
 				preferred_nid, nodemask);
 
-	if (new_page && PageTransHuge(page))
+	if (new_page && PageTransHuge(new_page))
 		prep_transhuge_page(new_page);
 
 	return new_page;
-- 
2.14.2