The patch titled
Subject: cma: Enforce non-zero pageblock_order during cma_init_reserved_mem()
has been added to the -mm mm-unstable branch. Its filename is
cma-enforce-non-zero-pageblock_order-during-cma_init_reserved_mem.patch
This patch will shortly appear at
https://git.kernel.org/pub/scm/linux/kernel/git/akpm/25-new.git/tree/patches/cma-enforce-non-zero-pageblock_order-during-cma_init_reserved_mem.patch
This patch will later appear in the mm-unstable branch at
git://git.kernel.org/pub/scm/linux/kernel/git/akpm/mm
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------------------------------------------------------
From: "Ritesh Harjani (IBM)" <ritesh.list@xxxxxxxxx>
Subject: cma: Enforce non-zero pageblock_order during cma_init_reserved_mem()
Date: Fri, 11 Oct 2024 20:26:09 +0530
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().
Link: https://lkml.kernel.org/r/054b416302486c2d3fdd5924b624477929100bf6.1728656994.git.ritesh.list@xxxxxxxxx
Signed-off-by: Ritesh Harjani (IBM) <ritesh.list@xxxxxxxxx>
Acked-by: David Hildenbrand <david@xxxxxxxxxx>
Acked-by: Zi Yan <ziy@xxxxxxxxxx>
Reviewed-by: Anshuman Khandual <anshuman.khandual@xxxxxxx>
Cc: Aneesh Kumar K.V <aneesh.kumar@xxxxxxxxxx>
Cc: Donet Tom <donettom@xxxxxxxxxxxxxxxxxx>
Cc: Hari Bathini <hbathini@xxxxxxxxxxxxx>
Cc: Kirill A. Shutemov <kirill.shutemov@xxxxxxxxxxxxxxx>
Cc: Madhavan Srinivasan <maddy@xxxxxxxxxxxxx>
Cc: Mahesh Salgaonkar <mahesh@xxxxxxxxxxxxx>
Cc: Michael Ellerman <mpe@xxxxxxxxxxxxxx>
Cc: Sachin P Bappalige <sachinpb@xxxxxxxxxxxxx>
Cc: Sourabh Jain <sourabhjain@xxxxxxxxxxxxx>
Cc: Zi Yan <ziy@xxxxxxxxxx>
Signed-off-by: Andrew Morton <akpm@xxxxxxxxxxxxxxxxxxxx>
---
mm/cma.c | 9 +++++++++
1 file changed, 9 insertions(+)
--- a/mm/cma.c~cma-enforce-non-zero-pageblock_order-during-cma_init_reserved_mem
+++ a/mm/cma.c
@@ -181,6 +181,15 @@ int __init cma_init_reserved_mem(phys_ad
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;
_
Patches currently in -mm which might be from ritesh.list@xxxxxxxxx are
cma-enforce-non-zero-pageblock_order-during-cma_init_reserved_mem.patch
