The patch titled
Subject: mm/page_isolation: fix isolate_single_pageblock() isolation behavior
has been added to the -mm mm-hotfixes-unstable branch. Its filename is
mm-page_isolation-fix-isolate_single_pageblock-isolation-behavior.patch
This patch will shortly appear at
https://git.kernel.org/pub/scm/linux/kernel/git/akpm/25-new.git/tree/patches/mm-page_isolation-fix-isolate_single_pageblock-isolation-behavior.patch
This patch will later appear in the mm-hotfixes-unstable branch at
git://git.kernel.org/pub/scm/linux/kernel/git/akpm/mm
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------------------------------------------------------
From: Zi Yan <ziy@xxxxxxxxxx>
Subject: mm/page_isolation: fix isolate_single_pageblock() isolation behavior
Date: Tue, 13 Sep 2022 22:39:13 -0400
set_migratetype_isolate() does not allow isolating MIGRATE_CMA pageblocks
unless it is used for CMA allocation. isolate_single_pageblock() did not
have the same behavior when it is used together with
set_migratetype_isolate() in start_isolate_page_range(). This allows
alloc_contig_range() with migratetype other than MIGRATE_CMA, like
MIGRATE_MOVABLE (used by alloc_contig_pages()), to isolate first and last
pageblock but fail the rest. The failure leads to changing migratetype of
the first and last pageblock to MIGRATE_MOVABLE from MIGRATE_CMA,
corrupting the CMA region. This can happen during gigantic page
allocations.
Fix it by passing migratetype into isolate_single_pageblock(), so that
set_migratetype_isolate() used by isolate_single_pageblock() will prevent
the isolation happening.
Link: https://lkml.kernel.org/r/20220914023913.1855924-1-zi.yan@xxxxxxxx
Fixes: b2c9e2fbba32 ("mm: make alloc_contig_range work at pageblock granularity")
Signed-off-by: Zi Yan <ziy@xxxxxxxxxx>
Reported-by: Doug Berger <opendmb@xxxxxxxxx>
Cc: David Hildenbrand <david@xxxxxxxxxx>
Cc: Doug Berger <opendmb@xxxxxxxxx>
Cc: Mike Kravetz <mike.kravetz@xxxxxxxxxx>
Cc: <stable@xxxxxxxxxxxxxxx>
Signed-off-by: Andrew Morton <akpm@xxxxxxxxxxxxxxxxxxxx>
---
mm/page_isolation.c | 25 ++++++++++++++-----------
1 file changed, 14 insertions(+), 11 deletions(-)
--- a/mm/page_isolation.c~mm-page_isolation-fix-isolate_single_pageblock-isolation-behavior
+++ a/mm/page_isolation.c
@@ -288,6 +288,7 @@ __first_valid_page(unsigned long pfn, un
* @isolate_before: isolate the pageblock before the boundary_pfn
* @skip_isolation: the flag to skip the pageblock isolation in second
* isolate_single_pageblock()
+ * @migratetype: migrate type to set in error recovery.
*
* Free and in-use pages can be as big as MAX_ORDER-1 and contain more than one
* pageblock. When not all pageblocks within a page are isolated at the same
@@ -302,9 +303,9 @@ __first_valid_page(unsigned long pfn, un
* the in-use page then splitting the free page.
*/
static int isolate_single_pageblock(unsigned long boundary_pfn, int flags,
- gfp_t gfp_flags, bool isolate_before, bool skip_isolation)
+ gfp_t gfp_flags, bool isolate_before, bool skip_isolation,
+ int migratetype)
{
- unsigned char saved_mt;
unsigned long start_pfn;
unsigned long isolate_pageblock;
unsigned long pfn;
@@ -328,13 +329,13 @@ static int isolate_single_pageblock(unsi
start_pfn = max(ALIGN_DOWN(isolate_pageblock, MAX_ORDER_NR_PAGES),
zone->zone_start_pfn);
- saved_mt = get_pageblock_migratetype(pfn_to_page(isolate_pageblock));
+ if (skip_isolation) {
+ int mt = get_pageblock_migratetype(pfn_to_page(isolate_pageblock));
- if (skip_isolation)
- VM_BUG_ON(!is_migrate_isolate(saved_mt));
- else {
- ret = set_migratetype_isolate(pfn_to_page(isolate_pageblock), saved_mt, flags,
- isolate_pageblock, isolate_pageblock + pageblock_nr_pages);
+ VM_BUG_ON(!is_migrate_isolate(mt));
+ } else {
+ ret = set_migratetype_isolate(pfn_to_page(isolate_pageblock), migratetype,
+ flags, isolate_pageblock, isolate_pageblock + pageblock_nr_pages);
if (ret)
return ret;
@@ -475,7 +476,7 @@ static int isolate_single_pageblock(unsi
failed:
/* restore the original migratetype */
if (!skip_isolation)
- unset_migratetype_isolate(pfn_to_page(isolate_pageblock), saved_mt);
+ unset_migratetype_isolate(pfn_to_page(isolate_pageblock), migratetype);
return -EBUSY;
}
@@ -537,7 +538,8 @@ int start_isolate_page_range(unsigned lo
bool skip_isolation = false;
/* isolate [isolate_start, isolate_start + pageblock_nr_pages) pageblock */
- ret = isolate_single_pageblock(isolate_start, flags, gfp_flags, false, skip_isolation);
+ ret = isolate_single_pageblock(isolate_start, flags, gfp_flags, false,
+ skip_isolation, migratetype);
if (ret)
return ret;
@@ -545,7 +547,8 @@ int start_isolate_page_range(unsigned lo
skip_isolation = true;
/* isolate [isolate_end - pageblock_nr_pages, isolate_end) pageblock */
- ret = isolate_single_pageblock(isolate_end, flags, gfp_flags, true, skip_isolation);
+ ret = isolate_single_pageblock(isolate_end, flags, gfp_flags, true,
+ skip_isolation, migratetype);
if (ret) {
unset_migratetype_isolate(pfn_to_page(isolate_start), migratetype);
return ret;
_
Patches currently in -mm which might be from ziy@xxxxxxxxxx are
mm-page_isolation-fix-isolate_single_pageblock-isolation-behavior.patch
