From: Oscar Salvador <osalvador@suse.de>
To: n-horiguchi@ah.jp.nec.com
Cc: mhocko@kernel.org, mike.kravetz@oracle.com, linux-mm@kvack.org,
linux-kernel@vger.kernel.org, Oscar Salvador <osalvador@suse.de>
Subject: [PATCH 02/10] mm,madvise: call soft_offline_page() without MF_COUNT_INCREASED
Date: Tue, 10 Sep 2019 12:30:08 +0200 [thread overview]
Message-ID: <20190910103016.14290-3-osalvador@suse.de> (raw)
In-Reply-To: <20190910103016.14290-1-osalvador@suse.de>
From: Naoya Horiguchi <n-horiguchi@ah.jp.nec.com>
Currently madvise_inject_error() pins the target via get_user_pages_fast.
The call to get_user_pages_fast is only to get the respective page
of a given address, but it is the job of the memory-poisoning handler
to deal with races, so drop the refcount grabbed by get_user_pages_fast.
Signed-off-by: Naoya Horiguchi <n-horiguchi@ah.jp.nec.com>
Signed-off-by: Oscar Salvador <osalvador@suse.de>
---
mm/madvise.c | 25 +++++++++++--------------
1 file changed, 11 insertions(+), 14 deletions(-)
diff --git a/mm/madvise.c b/mm/madvise.c
index 6e023414f5c1..fbe6d402232c 100644
--- a/mm/madvise.c
+++ b/mm/madvise.c
@@ -883,6 +883,16 @@ static int madvise_inject_error(int behavior,
ret = get_user_pages_fast(start, 1, 0, &page);
if (ret != 1)
return ret;
+ /*
+ * The get_user_pages_fast() is just to get the pfn of the
+ * given address, and the refcount has nothing to do with
+ * what we try to test, so it should be released immediately.
+ * This is racy but it's intended because the real hardware
+ * errors could happen at any moment and memory error handlers
+ * must properly handle the race.
+ */
+ put_page(page);
+
pfn = page_to_pfn(page);
/*
@@ -892,16 +902,11 @@ static int madvise_inject_error(int behavior,
*/
order = compound_order(compound_head(page));
- if (PageHWPoison(page)) {
- put_page(page);
- continue;
- }
-
if (behavior == MADV_SOFT_OFFLINE) {
pr_info("Soft offlining pfn %#lx at process virtual address %#lx\n",
pfn, start);
- ret = soft_offline_page(page, MF_COUNT_INCREASED);
+ ret = soft_offline_page(page, 0);
if (ret)
return ret;
continue;
@@ -909,14 +914,6 @@ static int madvise_inject_error(int behavior,
pr_info("Injecting memory failure for pfn %#lx at process virtual address %#lx\n",
pfn, start);
-
- /*
- * Drop the page reference taken by get_user_pages_fast(). In
- * the absence of MF_COUNT_INCREASED the memory_failure()
- * routine is responsible for pinning the page to prevent it
- * from being released back to the page allocator.
- */
- put_page(page);
ret = memory_failure(pfn, 0);
if (ret)
return ret;
--
2.12.3
next prev parent reply other threads:[~2019-09-10 10:31 UTC|newest]
Thread overview: 26+ messages / expand[flat|nested] mbox.gz Atom feed top
2019-09-10 10:30 [PATCH 00/10] Hwpoison soft-offline rework Oscar Salvador
2019-09-10 10:30 ` [PATCH 01/10] mm,hwpoison: cleanup unused PageHuge() check Oscar Salvador
2019-09-11 10:17 ` David Hildenbrand
2019-09-10 10:30 ` Oscar Salvador [this message]
2019-09-11 10:23 ` [PATCH 02/10] mm,madvise: call soft_offline_page() without MF_COUNT_INCREASED David Hildenbrand
2019-09-12 1:28 ` Naoya Horiguchi
2019-09-11 10:27 ` David Hildenbrand
2019-09-12 1:37 ` Naoya Horiguchi
2019-09-13 8:37 ` David Hildenbrand
2019-09-10 10:30 ` [PATCH 03/10] mm,hwpoison-inject: don't pin for hwpoison_filter Oscar Salvador
2019-09-16 7:41 ` David Hildenbrand
2019-09-10 10:30 ` [PATCH 04/10] mm,hwpoison: remove MF_COUNT_INCREASED Oscar Salvador
2019-09-11 10:24 ` David Hildenbrand
2019-09-10 10:30 ` [PATCH 05/10] mm: remove flag argument from soft offline functions Oscar Salvador
2019-09-11 10:24 ` David Hildenbrand
2019-09-10 10:30 ` [PATCH 06/10] mm,hwpoison: Unify THP handling for hard and soft offline Oscar Salvador
2019-09-10 10:30 ` [PATCH 07/10] mm,hwpoison: Rework soft offline for in-use pages Oscar Salvador
2019-09-10 10:30 ` [PATCH 08/10] mm,hwpoison: Refactor soft_offline_huge_page and __soft_offline_page Oscar Salvador
2019-09-10 10:30 ` [PATCH 09/10] mm,hwpoison: Rework soft offline for free pages Oscar Salvador
2019-09-10 10:30 ` [PATCH 10/10] mm,hwpoison: Use hugetlb_replace_page to replace free hugetlb pages Oscar Salvador
2019-09-10 10:32 ` [PATCH 00/10] Hwpoison soft-offline rework Oscar Salvador
2019-09-11 5:29 ` Naoya Horiguchi
2019-09-11 6:22 ` Naoya Horiguchi
2019-09-11 6:35 ` osalvador
2019-09-11 7:21 ` Naoya Horiguchi
2019-09-12 13:16 ` Oscar Salvador
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