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-c... and later at http://ozlabs.org/~akpm/mmotm/broken-out/mm-cma-fix-alloc_contig_range-ret-c...
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------------------------------------------------------ From: Mike Kravetz mike.kravetz@oracle.com 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@oracle.com Fixes: 8ef5849fa8a2 ("mm/cma: always check which page caused allocation failure") Signed-off-by: Mike Kravetz mike.kravetz@oracle.com Cc: Joonsoo Kim iamjoonsoo.kim@lge.com Cc: Laura Abbott labbott@redhat.com Cc: Vlastimil Babka vbabka@suse.cz Cc: Michal Nazarewicz mina86@mina86.com Cc: Michal Hocko mhocko@suse.com Cc: Mel Gorman mgorman@techsingularity.net Cc: Johannes Weiner hannes@cmpxchg.org Cc: stable@vger.kernel.org Signed-off-by: Andrew Morton akpm@linux-foundation.org ---
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@oracle.com are
mm-cma-fix-alloc_contig_range-ret-code-potential-leak.patch