[PATCH 3/3] of: reserved_mem: release dynamically allocated no-map region on init failure

[Wandun Chen <chenwandun1@gmail.com>]

From: Wandun Chen <chenwandun@lixiang.com>

Dynamically reserved-memory regions are added to memblock.reserved by
memblock_phys_alloc_range() during __reserved_mem_alloc_size(). When a
reserved-memory region's driver initialization fails,
fdt_init_reserved_mem_node() cleans up the reservation. For no-map
regions it only calls memblock_clear_nomap(), but leaves the entry in
memblock.reserved untouched, so the memory is never returned to the
buddy allocator.

Fix it by freeing the region on init failure when it was dynamically
allocated.

Sashiko found this issue in [1].

Fixes: 7b25995f5319 ("of: of_reserved_mem: mark nomap memory instead of removing")
Signed-off-by: Wandun Chen <chenwandun@lixiang.com>
Link: https://lore.kernel.org/all/20260806100605.2C2C01F000E9@smtp.kernel.org/ [1]
---
 drivers/of/of_reserved_mem.c | 13 ++++++++-----
 1 file changed, 8 insertions(+), 5 deletions(-)

diff --git a/drivers/of/of_reserved_mem.c b/drivers/of/of_reserved_mem.c
index 67cb60616fc6..d09c29184acf 100644
--- a/drivers/of/of_reserved_mem.c
+++ b/drivers/of/of_reserved_mem.c
@@ -125,7 +125,8 @@ static int __init alloc_reserved_mem_array(void)
 }
 
 static void fdt_init_reserved_mem_node(unsigned long node, const char *uname,
-				       phys_addr_t base, phys_addr_t size);
+				       phys_addr_t base, phys_addr_t size,
+				       bool dynamic);
 static int fdt_validate_reserved_mem_node(unsigned long node,
 					  phys_addr_t *align);
 static int fdt_fixup_reserved_mem_node(unsigned long node,
@@ -340,7 +341,7 @@ void __init fdt_scan_reserved_mem_late(void)
 			continue;
 
 		uname = fdt_get_name(fdt, child, NULL);
-		fdt_init_reserved_mem_node(child, uname, base, size);
+		fdt_init_reserved_mem_node(child, uname, base, size, false);
 	}
 
 	/* check for overlapping reserved regions */
@@ -556,7 +557,7 @@ static int __init __reserved_mem_alloc_size(unsigned long node, const char *unam
 	}
 
 	fdt_fixup_reserved_mem_node(node, base, size);
-	fdt_init_reserved_mem_node(node, uname, base, size);
+	fdt_init_reserved_mem_node(node, uname, base, size, true);
 
 	return 0;
 }
@@ -671,7 +672,8 @@ static int __init __reserved_mem_init_node(struct reserved_mem *rmem,
  * reserved_mem array to allow of_reserved_mem_lookup() to find it.
  */
 static void __init fdt_init_reserved_mem_node(unsigned long node, const char *uname,
-					      phys_addr_t base, phys_addr_t size)
+					      phys_addr_t base, phys_addr_t size,
+					      bool dynamic)
 {
 	int err = 0;
 	bool nomap;
@@ -697,7 +699,8 @@ static void __init fdt_init_reserved_mem_node(unsigned long node, const char *un
 
 		if (nomap)
 			memblock_clear_nomap(rmem->base, rmem->size);
-		else
+
+		if (dynamic || !nomap)
 			memblock_phys_free(rmem->base, rmem->size);
 		return;
 	} else {
-- 
2.43.0