The patch titled
Subject: mm/cma: fix alloc_contig_range ret code/potential leak
has been added to the -mm tree. Its filename is
mm-cma-fix-alloc_contig_range-ret-code-potential-leak.patch
This patch should soon appear at
http://ozlabs.org/~akpm/mmots/broken-out/mm-cma-fix-alloc_contig_range-ret-code-potential-leak.patch
and later at
http://ozlabs.org/~akpm/mmotm/broken-out/mm-cma-fix-alloc_contig_range-ret-code-potential-leak.patch
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------------------------------------------------------
From: Mike Kravetz <mike.kravetz@xxxxxxxxxx>
Subject: mm/cma: fix alloc_contig_range ret code/potential leak
If the call __alloc_contig_migrate_range() in alloc_contig_range returns
-EBUSY, processing continues so that test_pages_isolated() is called where
there is a tracepoint to identify the busy pages. However, it is possible
for busy pages to become available between the calls to these two
routines. In this case, the range of pages may be allocated.
Unfortunately, the original return code (ret == -EBUSY) is still set and
returned to the caller. Therefore, the caller believes the pages were not
allocated and they are leaked.
Update the return code with the value from test_pages_isolated().
Link: http://lkml.kernel.org/r/20171120193930.23428-2-mike.kravetz@xxxxxxxxxx
Fixes: 8ef5849fa8a2 ("mm/cma: always check which page caused allocation failure")
Signed-off-by: Mike Kravetz <mike.kravetz@xxxxxxxxxx>
Cc: Joonsoo Kim <iamjoonsoo.kim@xxxxxxx>
Cc: Laura Abbott <labbott@xxxxxxxxxx>
Cc: Vlastimil Babka <vbabka@xxxxxxx>
Cc: Michal Nazarewicz <mina86@xxxxxxxxxx>
Cc: Michal Hocko <mhocko@xxxxxxxx>
Cc: Mel Gorman <mgorman@xxxxxxxxxxxxxxxxxxx>
Cc: Johannes Weiner <hannes@xxxxxxxxxxx>
Cc: <stable@xxxxxxxxxxxxxxx>
Signed-off-by: Andrew Morton <akpm@xxxxxxxxxxxxxxxxxxxx>
---
mm/page_alloc.c | 4 ++--
1 file changed, 2 insertions(+), 2 deletions(-)
diff -puN mm/page_alloc.c~mm-cma-fix-alloc_contig_range-ret-code-potential-leak mm/page_alloc.c
--- a/mm/page_alloc.c~mm-cma-fix-alloc_contig_range-ret-code-potential-leak
+++ a/mm/page_alloc.c
@@ -7706,10 +7706,10 @@ int alloc_contig_range(unsigned long sta
}
/* Make sure the range is really isolated. */
- if (test_pages_isolated(outer_start, end, false)) {
+ ret = test_pages_isolated(outer_start, end, false);
+ if (ret) {
pr_info_ratelimited("%s: [%lx, %lx) PFNs busy\n",
__func__, outer_start, end);
- ret = -EBUSY;
goto done;
}
_
Patches currently in -mm which might be from mike.kravetz@xxxxxxxxxx are
mm-cma-fix-alloc_contig_range-ret-code-potential-leak.patch
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