The patch titled
Subject: mm/page_alloc: do bulk array bounds check after checking populated elements
has been added to the -mm tree. Its filename is
mm-page_alloc-do-bulk-array-bounds-check-after-checking-populated-elements.patch
This patch should soon appear at
https://ozlabs.org/~akpm/mmots/broken-out/mm-page_alloc-do-bulk-array-bounds-check-after-checking-populated-elements.patch
and later at
https://ozlabs.org/~akpm/mmotm/broken-out/mm-page_alloc-do-bulk-array-bounds-check-after-checking-populated-elements.patch
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------------------------------------------------------
From: Mel Gorman <mgorman@xxxxxxxxxxxxxxxxxxx>
Subject: 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@xxxxxxxxxxxxxxxxxxx
Fixes: 0f87d9d30f21 ("mm/page_alloc: add an array-based interface to the bulk page allocator")
Signed-off-by: Mel Gorman <mgorman@xxxxxxxxxxxxxxxxxxxx>
Reported-by: Dan Carpenter <dan.carpenter@xxxxxxxxxx>
Cc: Jesper Dangaard Brouer <brouer@xxxxxxxxxx>
Cc: Vlastimil Babka <vbabka@xxxxxxx>
Signed-off-by: Andrew Morton <akpm@xxxxxxxxxxxxxxxxxxxx>
---
mm/page_alloc.c | 4 ++++
1 file changed, 4 insertions(+)
--- a/mm/page_alloc.c~mm-page_alloc-do-bulk-array-bounds-check-after-checking-populated-elements
+++ a/mm/page_alloc.c
@@ -5056,6 +5056,10 @@ unsigned long __alloc_pages_bulk(gfp_t g
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;
_
Patches currently in -mm which might be from mgorman@xxxxxxxxxxxxxxxxxxx are
mm-page_alloc-do-bulk-array-bounds-check-after-checking-populated-elements.patch
mm-page_alloc-split-per-cpu-page-lists-and-zone-stats.patch
mm-page_alloc-split-per-cpu-page-lists-and-zone-stats-fix.patch
mm-page_alloc-split-per-cpu-page-lists-and-zone-stats-fix-fix.patch
mm-page_alloc-convert-per-cpu-list-protection-to-local_lock.patch
mm-page_alloc-convert-per-cpu-list-protection-to-local_lock-fix.patch
mm-vmstat-convert-numa-statistics-to-basic-numa-counters.patch
mm-vmstat-inline-numa-event-counter-updates.patch
mm-page_alloc-batch-the-accounting-updates-in-the-bulk-allocator.patch
mm-page_alloc-reduce-duration-that-irqs-are-disabled-for-vm-counters.patch
mm-page_alloc-explicitly-acquire-the-zone-lock-in-__free_pages_ok.patch
mm-page_alloc-avoid-conflating-irqs-disabled-with-zone-lock.patch
mm-page_alloc-update-pgfree-outside-the-zone-lock-in-__free_pages_ok.patch
mm-page_alloc-delete-vmpercpu_pagelist_fraction.patch
mm-page_alloc-disassociate-the-pcp-high-from-pcp-batch.patch
mm-page_alloc-disassociate-the-pcp-high-from-pcp-batch-fix-2.patch
mm-page_alloc-adjust-pcp-high-after-cpu-hotplug-events.patch
mm-page_alloc-scale-the-number-of-pages-that-are-batch-freed.patch
mm-page_alloc-limit-the-number-of-pages-on-pcp-lists-when-reclaim-is-active.patch
mm-page_alloc-introduce-vmpercpu_pagelist_high_fraction.patch
mm-page_alloc-introduce-vmpercpu_pagelist_high_fraction-fix.patch
mm-page_alloc-move-free_the_page.patch
mm-page_alloc-allow-high-order-pages-to-be-stored-on-the-per-cpu-lists.patch
mm-page_alloc-split-pcp-high-across-all-online-cpus-for-cpuless-nodes.patch
mm-vmscan-remove-kerneldoc-like-comment-from-isolate_lru_pages.patch
mm-vmalloc-include-header-for-prototype-of-set_iounmap_nonlazy.patch
mm-page_alloc-make-should_fail_alloc_page-a-static-function-should_fail_alloc_page-static.patch
mm-mapping_dirty_helpers-remove-double-note-in-kerneldoc.patch
mm-memcontrolc-fix-kerneldoc-comment-for-mem_cgroup_calculate_protection.patch
mm-memory_hotplug-fix-kerneldoc-comment-for-__try_online_node.patch
mm-memory_hotplug-fix-kerneldoc-comment-for-__remove_memory.patch
mm-zbud-add-kerneldoc-fields-for-zbud_pool.patch
mm-z3fold-add-kerneldoc-fields-for-z3fold_pool.patch
mm-swap-make-swap_address_space-an-inline-function.patch
mm-mmap_lock-remove-dead-code-for-config_tracing-configurations.patch
mm-page_alloc-move-prototype-for-find_suitable_fallback.patch
mm-swap-make-node_data-an-inline-function-on-config_flatmem.patch
