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Subject[PATCH 7/8 linux-next] mm: warn about possible alignment problem
Commit 5f29a77cd957
("mm: fix mixed zone detection in devm_memremap_pages")
Aligned resource limits before region_intersects() which breaks
the following with false assertions on kernel command line: memmap=4M!700M

"devm_memremap_pages attempted on mixed region [ mem 0x2bc00000-0x2bfffff
flags 0x200]"

Memory regions
0x100000-0x2bbfffff: usable
0x2bc000000-0x2bbfffff: persistent
0x2c0000000-0x2bffffff: usable

resource start: 0x2bc00000
align start: 0x28000000
resource size: 0x3fffffff
align size: 0x80000000
SECTION_SIZE: 0x8000000

Now we need aligned memmap declarations based on 128M in this case
eg memmap=128!640M

Signed-off-by: Fabian Frederick <>
kernel/memremap.c | 4 ++--
1 file changed, 2 insertions(+), 2 deletions(-)

diff --git a/kernel/memremap.c b/kernel/memremap.c
index b501e39..1bb5eec 100644
--- a/kernel/memremap.c
+++ b/kernel/memremap.c
@@ -296,8 +296,8 @@ void *devm_memremap_pages(struct device *dev, struct resource *res,

if (is_ram == REGION_MIXED) {
- WARN_ONCE(1, "%s attempted on mixed region %pr\n",
- __func__, res);
+ WARN_ONCE(1, "%s attempted on mixed region %pr or arguments not aligned to section size: %#lx\n",
+ __func__, res, SECTION_SIZE);
return ERR_PTR(-ENXIO);

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