On 11.10.24 09:23, Ritesh Harjani (IBM) wrote:
cma_init_reserved_mem() checks base and size alignment with
CMA_MIN_ALIGNMENT_BYTES. However, some users might call this during
early boot when pageblock_order is 0. That means if base and size does
not have pageblock_order alignment, it can cause functional failures
during cma activate area.

So let's enforce pageblock_order to be non-zero during
cma_init_reserved_mem().

Signed-off-by: Ritesh Harjani (IBM) <ritesh.l...@gmail.com>
---
  mm/cma.c | 9 +++++++++
  1 file changed, 9 insertions(+)

diff --git a/mm/cma.c b/mm/cma.c
index 3e9724716bad..36d753e7a0bf 100644
--- a/mm/cma.c
+++ b/mm/cma.c
@@ -182,6 +182,15 @@ int __init cma_init_reserved_mem(phys_addr_t base, 
phys_addr_t size,
        if (!size || !memblock_is_region_reserved(base, size))
                return -EINVAL;
+ /*
+        * CMA uses CMA_MIN_ALIGNMENT_BYTES as alignment requirement which
+        * needs pageblock_order to be initialized. Let's enforce it.
+        */
+       if (!pageblock_order) {
+               pr_err("pageblock_order not yet initialized. Called during early 
boot?\n");
+               return -EINVAL;
+       }
+
        /* ensure minimal alignment required by mm core */
        if (!IS_ALIGNED(base | size, CMA_MIN_ALIGNMENT_BYTES))
                return -EINVAL;


Acked-by: David Hildenbrand <da...@redhat.com>

--
Cheers,

David / dhildenb


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