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Subject[PATCH v4] mm/hugetlb: avoid hardcoding while checking if cma is enabled
hugetlb_cma[0] can be NULL due to various reasons, for example, node0 has
no memory. so NULL hugetlb_cma[0] doesn't necessarily mean cma is not
enabled. gigantic pages might have been reserved on other nodes.
This patch fixes possible double reservation and CMA leak.

Fixes: cf11e85fc08c ("mm: hugetlb: optionally allocate gigantic hugepages using cma")
Cc: Mike Kravetz <>
Cc: Jonathan Cameron <>
Acked-by: Roman Gushchin <>
Signed-off-by: Barry Song <>
v4: address linux-next issue;
use hugetlb_cma_size to check if cma is enabled

mm/hugetlb.c | 4 ++--
1 file changed, 2 insertions(+), 2 deletions(-)

diff --git a/mm/hugetlb.c b/mm/hugetlb.c
index 57ece74e3aae..bc3304af40d0 100644
--- a/mm/hugetlb.c
+++ b/mm/hugetlb.c
@@ -46,6 +46,7 @@ unsigned int default_hstate_idx;
struct hstate hstates[HUGE_MAX_HSTATE];

static struct cma *hugetlb_cma[MAX_NUMNODES];
+static unsigned long hugetlb_cma_size __initdata;

* Minimum page order among possible hugepage sizes, set to a proper value
@@ -2571,7 +2572,7 @@ static void __init hugetlb_hstate_alloc_pages(struct hstate *h)

for (i = 0; i < h->max_huge_pages; ++i) {
if (hstate_is_gigantic(h)) {
- if (IS_ENABLED(CONFIG_CMA) && hugetlb_cma[0]) {
+ if (hugetlb_cma_size) {
pr_warn_once("HugeTLB: hugetlb_cma is enabled, skip boot time allocation\n");
@@ -5654,7 +5655,6 @@ void move_hugetlb_state(struct page *oldpage, struct page *newpage, int reason)

-static unsigned long hugetlb_cma_size __initdata;
static bool cma_reserve_called __initdata;

static int __init cmdline_parse_hugetlb_cma(char *p)

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