diff options
| author | Mel Gorman <mgorman@techsingularity.net> | 2021-06-24 18:40:07 -0700 |
|---|---|---|
| committer | Linus Torvalds <torvalds@linux-foundation.org> | 2021-06-24 19:40:54 -0700 |
| commit | b3b64ebd38225d8032b5db42938d969b602040c2 (patch) | |
| tree | c5002be80ee46f6ee3e49e1c34a3ed5c3dc2458a | |
| parent | b08e50dd64489e3997029d204f761cb57a3762d2 (diff) | |
mm/page_alloc: do bulk array bounds check after checking populated elements
Dan Carpenter reported the following
The patch 0f87d9d30f21: "mm/page_alloc: add an array-based interface
to the bulk page allocator" from Apr 29, 2021, leads to the following
static checker warning:
mm/page_alloc.c:5338 __alloc_pages_bulk()
warn: potentially one past the end of array 'page_array[nr_populated]'
The problem can occur if an array is passed in that is fully populated.
That potentially ends up allocating a single page and storing it past
the end of the array. This patch returns 0 if the array is fully
populated.
Link: https://lkml.kernel.org/r/20210618125102.GU30378@techsingularity.net
Fixes: 0f87d9d30f21 ("mm/page_alloc: add an array-based interface to the bulk page allocator")
Signed-off-by: Mel Gorman <mgorman@techsinguliarity.net>
Reported-by: Dan Carpenter <dan.carpenter@oracle.com>
Cc: Jesper Dangaard Brouer <brouer@redhat.com>
Cc: Vlastimil Babka <vbabka@suse.cz>
Signed-off-by: Andrew Morton <akpm@linux-foundation.org>
Signed-off-by: Linus Torvalds <torvalds@linux-foundation.org>
| -rw-r--r-- | mm/page_alloc.c | 4 |
1 files changed, 4 insertions, 0 deletions
diff --git a/mm/page_alloc.c b/mm/page_alloc.c index 7124bb00219d..ef2265f86b91 100644 --- a/mm/page_alloc.c +++ b/mm/page_alloc.c @@ -5056,6 +5056,10 @@ unsigned long __alloc_pages_bulk(gfp_t gfp, int preferred_nid, while (page_array && nr_populated < nr_pages && page_array[nr_populated]) nr_populated++; + /* Already populated array? */ + if (unlikely(page_array && nr_pages - nr_populated == 0)) + return 0; + /* Use the single page allocator for one page. */ if (nr_pages - nr_populated == 1) goto failed; |