[PATCH 07/10] of/fdt: Fix the len check in early_init_dt_check_for_usable_mem_range()

From: Yuntao Wang

Date: Wed Nov 12 2025 - 09:38:14 EST


The len value is in bytes, while `dt_root_addr_cells + dt_root_size_cells`
is in cells (4 bytes per cell).

The modulo calculation between them is incorrect, the units must be
converted first.

Fixes: fb319e77a0e7 ("of: fdt: Add memory for devices by DT property "linux,usable-memory-range"")
Signed-off-by: Yuntao Wang <yuntao.wang@xxxxxxxxx>
---
drivers/of/fdt.c | 2 +-
1 file changed, 1 insertion(+), 1 deletion(-)

diff --git a/drivers/of/fdt.c b/drivers/of/fdt.c
index 716ebe8c23d3..0f95f3b356ea 100644
--- a/drivers/of/fdt.c
+++ b/drivers/of/fdt.c
@@ -859,7 +859,7 @@ void __init early_init_dt_check_for_usable_mem_range(void)
pr_debug("Looking for usable-memory-range property... ");

prop = of_get_flat_dt_prop(node, "linux,usable-memory-range", &len);
- if (!prop || (len % (dt_root_addr_cells + dt_root_size_cells)))
+ if (!prop || len % dt_root_addr_size_bytes())
return;

endp = prop + (len / sizeof(__be32));
--
2.51.0