From: Andrew Morton akpm@linux-foundation.org
mainline inclusion from mainline-v5.11-rc1 commit 34fe653716b0d340bc26dd4823d2dbe00c57f849 category: bugfix bugzilla: NA CVE: NA
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With a machine with 3 TB (more than 2 TB memory). If you use vmalloc to allocate > 2 TB memory, the array_size below will be overflowed.
The array_size is an unsigned int and can only be used to allocate less than 2 TB memory. If you pass 2*1028*1028*1024*1024 = 2 * 2^40 in the argument of vmalloc. The array_size will become 2*2^31 = 2^32. The 2^32 cannot be store with a 32 bit integer.
The fix is to change the type of array_size to unsigned long.
[akpm@linux-foundation.org: rework for current mainline]
Link: https://bugzilla.kernel.org/show_bug.cgi?id=210023 Reported-by: hsinhuiwu@gmail.com Cc: Matthew Wilcox willy@infradead.org Signed-off-by: Andrew Morton akpm@linux-foundation.org Signed-off-by: Linus Torvalds torvalds@linux-foundation.org
conflict: mm/vmalloc.c
Signed-off-by: Tong Tiangen tongtiangen@huawei.com Reviewed-by: Chen Wandun chenwandun@huawei.com Signed-off-by: Yang Yingliang yangyingliang@huawei.com --- mm/vmalloc.c | 6 ++++-- 1 file changed, 4 insertions(+), 2 deletions(-)
diff --git a/mm/vmalloc.c b/mm/vmalloc.c index 011a84ebec04d..7750fd379633e 100644 --- a/mm/vmalloc.c +++ b/mm/vmalloc.c @@ -2565,7 +2565,9 @@ static void *__vmalloc_area_node(struct vm_struct *area, gfp_t gfp_mask, unsigned long addr = (unsigned long)area->addr; unsigned long size = get_vm_area_size(area); unsigned int page_order = page_shift - PAGE_SHIFT; - unsigned int nr_pages, array_size, i; + unsigned int nr_pages; + unsigned long array_size; + unsigned int i; const gfp_t nested_gfp = (gfp_mask & GFP_RECLAIM_MASK) | __GFP_ZERO; const gfp_t alloc_mask = gfp_mask | __GFP_NOWARN; const gfp_t highmem_mask = (gfp_mask & (GFP_DMA | GFP_DMA32)) ? @@ -2573,7 +2575,7 @@ static void *__vmalloc_area_node(struct vm_struct *area, gfp_t gfp_mask, __GFP_HIGHMEM;
nr_pages = size >> PAGE_SHIFT; - array_size = (nr_pages * sizeof(struct page *)); + array_size = (unsigned long)nr_pages * sizeof(struct page *);
/* Please note that the recursion is strictly bounded. */ if (array_size > PAGE_SIZE) {