The patch titled
Subject: mm/page_alloc: check high-order pages for corruption during PCP operations
has been added to the -mm tree. Its filename is
mm-page_alloc-check-high-order-pages-for-corruption-during-pcp-operations.patch
This patch should soon appear at
https://ozlabs.org/~akpm/mmots/broken-out/mm-page_alloc-check-high-order-pages-for-corruption-during-pcp-operations.patch
and later at
https://ozlabs.org/~akpm/mmotm/broken-out/mm-page_alloc-check-high-order-pages-for-corruption-during-pcp-operations.patch
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------------------------------------------------------
From: Mel Gorman <mgorman@xxxxxxxxxxxxxxxxxxx>
Subject: mm/page_alloc: check high-order pages for corruption during PCP operations
Eric Dumazet pointed out that commit 44042b449872 ("mm/page_alloc: allow
high-order pages to be stored on the per-cpu lists") only checks the head
page during PCP refill and allocation operations. This was an oversight
and all pages should be checked. This will incur a small performance
penalty but it's necessary for correctness.
Link: https://lkml.kernel.org/r/20220310092456.GJ15701@xxxxxxxxxxxxxxxxxxx
Fixes: 44042b449872 ("mm/page_alloc: allow high-order pages to be stored on the per-cpu lists")
Signed-off-by: Mel Gorman <mgorman@xxxxxxxxxxxxxxxxxxx>
Reported-by: Eric Dumazet <edumazet@xxxxxxxxxx>
Acked-by: Eric Dumazet <edumazet@xxxxxxxxxx>
Reviewed-by: Shakeel Butt <shakeelb@xxxxxxxxxx>
Acked-by: Vlastimil Babka <vbabka@xxxxxxx>
Acked-by: David Rientjes <rientjes@xxxxxxxxxx>
Cc: Michal Hocko <mhocko@xxxxxxxxxx>
Cc: Wei Xu <weixugc@xxxxxxxxxx>
Cc: Greg Thelen <gthelen@xxxxxxxxxx>
Cc: Hugh Dickins <hughd@xxxxxxxxxx>
Signed-off-by: Andrew Morton <akpm@xxxxxxxxxxxxxxxxxxxx>
---
mm/page_alloc.c | 46 +++++++++++++++++++++++-----------------------
1 file changed, 23 insertions(+), 23 deletions(-)
--- a/mm/page_alloc.c~mm-page_alloc-check-high-order-pages-for-corruption-during-pcp-operations
+++ a/mm/page_alloc.c
@@ -2291,23 +2291,36 @@ static inline int check_new_page(struct
return 1;
}
+static bool check_new_pages(struct page *page, unsigned int order)
+{
+ int i;
+ for (i = 0; i < (1 << order); i++) {
+ struct page *p = page + i;
+
+ if (unlikely(check_new_page(p)))
+ return true;
+ }
+
+ return false;
+}
+
#ifdef CONFIG_DEBUG_VM
/*
* With DEBUG_VM enabled, order-0 pages are checked for expected state when
* being allocated from pcp lists. With debug_pagealloc also enabled, they are
* also checked when pcp lists are refilled from the free lists.
*/
-static inline bool check_pcp_refill(struct page *page)
+static inline bool check_pcp_refill(struct page *page, unsigned int order)
{
if (debug_pagealloc_enabled_static())
- return check_new_page(page);
+ return check_new_pages(page, order);
else
return false;
}
-static inline bool check_new_pcp(struct page *page)
+static inline bool check_new_pcp(struct page *page, unsigned int order)
{
- return check_new_page(page);
+ return check_new_pages(page, order);
}
#else
/*
@@ -2315,32 +2328,19 @@ static inline bool check_new_pcp(struct
* when pcp lists are being refilled from the free lists. With debug_pagealloc
* enabled, they are also checked when being allocated from the pcp lists.
*/
-static inline bool check_pcp_refill(struct page *page)
+static inline bool check_pcp_refill(struct page *page, unsigned int order)
{
- return check_new_page(page);
+ return check_new_pages(page, order);
}
-static inline bool check_new_pcp(struct page *page)
+static inline bool check_new_pcp(struct page *page, unsigned int order)
{
if (debug_pagealloc_enabled_static())
- return check_new_page(page);
+ return check_new_pages(page, order);
else
return false;
}
#endif /* CONFIG_DEBUG_VM */
-static bool check_new_pages(struct page *page, unsigned int order)
-{
- int i;
- for (i = 0; i < (1 << order); i++) {
- struct page *p = page + i;
-
- if (unlikely(check_new_page(p)))
- return true;
- }
-
- return false;
-}
-
inline void post_alloc_hook(struct page *page, unsigned int order,
gfp_t gfp_flags)
{
@@ -2982,7 +2982,7 @@ static int rmqueue_bulk(struct zone *zon
if (unlikely(page == NULL))
break;
- if (unlikely(check_pcp_refill(page)))
+ if (unlikely(check_pcp_refill(page, order)))
continue;
/*
@@ -3600,7 +3600,7 @@ struct page *__rmqueue_pcplist(struct zo
page = list_first_entry(list, struct page, lru);
list_del(&page->lru);
pcp->count -= 1 << order;
- } while (check_new_pcp(page));
+ } while (check_new_pcp(page, order));
return page;
}
_
Patches currently in -mm which might be from mgorman@xxxxxxxxxxxxxxxxxxx are
mm-page_alloc-fetch-the-correct-pcp-buddy-during-bulk-free.patch
mm-page_alloc-track-range-of-active-pcp-lists-during-bulk-free.patch
mm-page_alloc-simplify-how-many-pages-are-selected-per-pcp-list-during-bulk-free.patch
mm-page_alloc-drain-the-requested-list-first-during-bulk-free.patch
mm-page_alloc-free-pages-in-a-single-pass-during-bulk-free.patch
mm-page_alloc-limit-number-of-high-order-pages-on-pcp-during-bulk-free.patch
mm-page_alloc-do-not-prefetch-buddies-during-bulk-free.patch
mm-page_alloc-check-high-order-pages-for-corruption-during-pcp-operations.patch
