From: Dan Williams <dan.j.williams@intel.com>
To: akpm@linux-foundation.org
Cc: Naoya Horiguchi <nao.horiguchi@gmail.com>,
Michal Hocko <mhocko@kernel.org>,
David Hildenbrand <david@redhat.com>,
Oscar Salvador <osalvador@suse.de>,
stable@vger.kernel.org, linux-mm@kvack.org,
linux-nvdimm@lists.01.org, linux-kernel@vger.kernel.org
Subject: [PATCH v4 4/5] mm: Fix page reference leak in soft_offline_page()
Date: Wed, 13 Jan 2021 16:43:32 -0800 [thread overview]
Message-ID: <161058501210.1840162.8108917599181157327.stgit@dwillia2-desk3.amr.corp.intel.com> (raw)
In-Reply-To: <161058499000.1840162.702316708443239771.stgit@dwillia2-desk3.amr.corp.intel.com>
The conversion to move pfn_to_online_page() internal to
soft_offline_page() missed that the get_user_pages() reference taken by
the madvise() path needs to be dropped when pfn_to_online_page() fails.
Note the direct sysfs-path to soft_offline_page() does not perform a
get_user_pages() lookup.
When soft_offline_page() is handed a pfn_valid() &&
!pfn_to_online_page() pfn the kernel hangs at dax-device shutdown due to
a leaked reference.
Fixes: feec24a6139d ("mm, soft-offline: convert parameter to pfn")
Cc: Andrew Morton <akpm@linux-foundation.org>
Cc: Naoya Horiguchi <nao.horiguchi@gmail.com>
Cc: Michal Hocko <mhocko@kernel.org>
Reviewed-by: David Hildenbrand <david@redhat.com>
Reviewed-by: Oscar Salvador <osalvador@suse.de>
Cc: <stable@vger.kernel.org>
Signed-off-by: Dan Williams <dan.j.williams@intel.com>
---
mm/memory-failure.c | 20 ++++++++++++++++----
1 file changed, 16 insertions(+), 4 deletions(-)
diff --git a/mm/memory-failure.c b/mm/memory-failure.c
index 5a38e9eade94..78b173c7190c 100644
--- a/mm/memory-failure.c
+++ b/mm/memory-failure.c
@@ -1885,6 +1885,12 @@ static int soft_offline_free_page(struct page *page)
return rc;
}
+static void put_ref_page(struct page *page)
+{
+ if (page)
+ put_page(page);
+}
+
/**
* soft_offline_page - Soft offline a page.
* @pfn: pfn to soft-offline
@@ -1910,20 +1916,26 @@ static int soft_offline_free_page(struct page *page)
int soft_offline_page(unsigned long pfn, int flags)
{
int ret;
- struct page *page;
bool try_again = true;
+ struct page *page, *ref_page = NULL;
+
+ WARN_ON_ONCE(!pfn_valid(pfn) && (flags & MF_COUNT_INCREASED));
if (!pfn_valid(pfn))
return -ENXIO;
+ if (flags & MF_COUNT_INCREASED)
+ ref_page = pfn_to_page(pfn);
+
/* Only online pages can be soft-offlined (esp., not ZONE_DEVICE). */
page = pfn_to_online_page(pfn);
- if (!page)
+ if (!page) {
+ put_ref_page(ref_page);
return -EIO;
+ }
if (PageHWPoison(page)) {
pr_info("%s: %#lx page already poisoned\n", __func__, pfn);
- if (flags & MF_COUNT_INCREASED)
- put_page(page);
+ put_ref_page(ref_page);
return 0;
}
next prev parent reply other threads:[~2021-01-14 1:47 UTC|newest]
Thread overview: 16+ messages / expand[flat|nested] mbox.gz Atom feed top
2021-01-14 0:43 [PATCH v4 0/5] mm: Fix pfn_to_online_page() with respect to ZONE_DEVICE Dan Williams
2021-01-14 0:43 ` [PATCH v4 1/5] mm: Move pfn_to_online_page() out of line Dan Williams
2021-01-20 10:11 ` Michal Hocko
2021-01-14 0:43 ` [PATCH v4 2/5] mm: Teach pfn_to_online_page() to consider subsection validity Dan Williams
2021-01-20 10:24 ` Michal Hocko
2021-01-14 0:43 ` [PATCH v4 3/5] mm: Teach pfn_to_online_page() about ZONE_DEVICE section collisions Dan Williams
2021-01-20 10:30 ` Michal Hocko
2021-01-14 0:43 ` Dan Williams [this message]
2021-01-14 1:49 ` [PATCH v4 4/5] mm: Fix page reference leak in soft_offline_page() HORIGUCHI NAOYA(堀口 直也)
2021-01-14 6:18 ` Dan Williams
2021-01-14 6:30 ` Oscar Salvador
2021-01-14 7:10 ` HORIGUCHI NAOYA(堀口 直也)
2021-01-17 22:01 ` Andrew Morton
2021-01-17 22:35 ` Dan Williams
2021-01-14 0:43 ` [PATCH v4 5/5] mm: Fix memory_failure() handling of dax-namespace metadata Dan Williams
2021-01-14 2:25 ` HORIGUCHI NAOYA(堀口 直也)
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