linux-kernel - [PATCH 4/8] HWPOISON, hugetlb: set/clear PG

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: <1275006562-18946-5-git-send-email-n-horiguchi@ah.jp.nec.com>
Date:	Fri, 28 May 2010 09:29:18 +0900
From:	Naoya Horiguchi <n-horiguchi@...jp.nec.com>
To:	linux-mm@...ck.org
Cc:	linux-kernel@...r.kernel.org, Andi Kleen <andi@...stfloor.org>,
	Andrew Morton <akpm@...ux-foundation.org>,
	Wu Fengguang <fengguang.wu@...el.com>,
	Mel Gorman <mel@....ul.ie>
Subject: [PATCH 4/8] HWPOISON, hugetlb: set/clear PG_hwpoison bits on hugepage

To avoid race condition between concurrent memory errors on identified
hugepage, we atomically test and set PG_hwpoison bit on the head page.
All pages in the error hugepage are considered as hwpoisoned
for now, so set and clear all PG_hwpoison bits in the hugepage
with page lock of the head page held.

Dependency:
  "HWPOISON, hugetlb: enable error handling path for hugepage"

Signed-off-by: Naoya Horiguchi <n-horiguchi@...jp.nec.com>
Cc: Andi Kleen <andi@...stfloor.org>
Cc: Andrew Morton <akpm@...ux-foundation.org>
Cc: Wu Fengguang <fengguang.wu@...el.com>
---
 mm/memory-failure.c |   38 ++++++++++++++++++++++++++++++++++++++
 1 files changed, 38 insertions(+), 0 deletions(-)

diff --git v2.6.34/mm/memory-failure.c v2.6.34/mm/memory-failure.c
index 1ec68c8..fee648b 100644
--- v2.6.34/mm/memory-failure.c
+++ v2.6.34/mm/memory-failure.c
@@ -920,6 +920,22 @@ static int hwpoison_user_mappings(struct page *p, unsigned long pfn,
 	return ret;
 }
 
+static void set_page_hwpoison_huge_page(struct page *hpage)
+{
+	int i;
+	int nr_pages = 1 << compound_order(hpage);
+	for (i = 0; i < nr_pages; i++)
+		SetPageHWPoison(hpage + i);
+}
+
+static void clear_page_hwpoison_huge_page(struct page *hpage)
+{
+	int i;
+	int nr_pages = 1 << compound_order(hpage);
+	for (i = 0; i < nr_pages; i++)
+		ClearPageHWPoison(hpage + i);
+}
+
 int __memory_failure(unsigned long pfn, int trapno, int flags)
 {
 	struct page_state *ps;
@@ -1014,6 +1030,26 @@ int __memory_failure(unsigned long pfn, int trapno, int flags)
 		return 0;
 	}
 
+	/*
+	 * For error on the tail page, we should set PG_hwpoison
+	 * on the head page to show that the hugepage is hwpoisoned
+	 */
+	if (PageTail(p) && TestSetPageHWPoison(hpage)) {
+		action_result(pfn, "hugepage already hardware poisoned",
+				IGNORED);
+		unlock_page(hpage);
+		put_page(hpage);
+		return 0;
+	}
+	/*
+	 * Set PG_hwpoison on all pages in an error hugepage,
+	 * because containment is done in hugepage unit for now.
+	 * Since we have done TestSetPageHWPoison() for the head page with
+	 * page lock held, we can safely set PG_hwpoison bits on tail pages.
+	 */
+	if (PageHuge(p))
+		set_page_hwpoison_huge_page(hpage);
+
 	wait_on_page_writeback(p);
 
 	/*
@@ -1118,6 +1154,8 @@ int unpoison_memory(unsigned long pfn)
 		atomic_long_dec(&mce_bad_pages);
 		freeit = 1;
 	}
+	if (PageHuge(p))
+		clear_page_hwpoison_huge_page(page);
 	unlock_page(page);
 
 	put_page(page);
-- 
1.7.0

--
To unsubscribe from this list: send the line "unsubscribe linux-kernel" in
the body of a message to majordomo@...r.kernel.org
More majordomo info at  http://vger.kernel.org/majordomo-info.html
Please read the FAQ at  http://www.tux.org/lkml/