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| author | Muchun Song <songmuchun@bytedance.com> | 2023-03-23 10:50:03 +0800 |
|---|---|---|
| committer | Andrew Morton <akpm@linux-foundation.org> | 2023-03-28 15:24:32 -0700 |
| commit | 1f2803b2660f4b04d48d065072c0ae0c9ca255fd (patch) | |
| tree | 2c910d40709646893afef8ee0e804d86b42b2790 /mm/kfence | |
| parent | 3ee2d7471fa4963a2ced0a84f0653ce88b43c5b2 (diff) | |
| download | lwn-1f2803b2660f4b04d48d065072c0ae0c9ca255fd.tar.gz lwn-1f2803b2660f4b04d48d065072c0ae0c9ca255fd.zip | |
mm: kfence: fix handling discontiguous page
The struct pages could be discontiguous when the kfence pool is allocated
via alloc_contig_pages() with CONFIG_SPARSEMEM and
!CONFIG_SPARSEMEM_VMEMMAP.
This may result in setting PG_slab and memcg_data to a arbitrary
address (may be not used as a struct page), which in the worst case
might corrupt the kernel.
So the iteration should use nth_page().
Link: https://lkml.kernel.org/r/20230323025003.94447-1-songmuchun@bytedance.com
Fixes: 0ce20dd84089 ("mm: add Kernel Electric-Fence infrastructure")
Signed-off-by: Muchun Song <songmuchun@bytedance.com>
Reviewed-by: Marco Elver <elver@google.com>
Reviewed-by: Kefeng Wang <wangkefeng.wang@huawei.com>
Cc: Alexander Potapenko <glider@google.com>
Cc: Dmitry Vyukov <dvyukov@google.com>
Cc: Jann Horn <jannh@google.com>
Cc: SeongJae Park <sjpark@amazon.de>
Cc: <stable@vger.kernel.org>
Signed-off-by: Andrew Morton <akpm@linux-foundation.org>
Diffstat (limited to 'mm/kfence')
| -rw-r--r-- | mm/kfence/core.c | 4 |
1 files changed, 2 insertions, 2 deletions
diff --git a/mm/kfence/core.c b/mm/kfence/core.c index d66092dd187c..1065e0568d05 100644 --- a/mm/kfence/core.c +++ b/mm/kfence/core.c @@ -556,7 +556,7 @@ static unsigned long kfence_init_pool(void) * enters __slab_free() slow-path. */ for (i = 0; i < KFENCE_POOL_SIZE / PAGE_SIZE; i++) { - struct slab *slab = page_slab(&pages[i]); + struct slab *slab = page_slab(nth_page(pages, i)); if (!i || (i % 2)) continue; @@ -602,7 +602,7 @@ static unsigned long kfence_init_pool(void) reset_slab: for (i = 0; i < KFENCE_POOL_SIZE / PAGE_SIZE; i++) { - struct slab *slab = page_slab(&pages[i]); + struct slab *slab = page_slab(nth_page(pages, i)); if (!i || (i % 2)) continue; |