[PATCH v2 4/5] of: reserved_mem: release dynamically allocated no-map region on init failure

[Wandun Chen]

From: Wandun Chen <chenwandun@xxxxxxxxxxx>

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(), leaving the range in
memblock.reserved and unavailable for normal memory use.

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@xxxxxxxxxxx>
Link: https://sashiko.dev/#/message/20260806100605.2C2C01F000E9%40smtp.kernel.org [1]
---
 drivers/of/of_reserved_mem.c | 14 +++++++++-----
 1 file changed, 9 insertions(+), 5 deletions(-)

diff --git a/drivers/of/of_reserved_mem.c b/drivers/of/of_reserved_mem.c
index 767ef702392e..ac5db19dcc93 100644
--- a/drivers/of/of_reserved_mem.c
+++ b/drivers/of/of_reserved_mem.c
@@ -136,7 +136,8 @@ 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,
@@ -352,7 +353,7 @@ 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 */
@@ -567,7 +568,7 @@ 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;
 }
@@ -676,13 +677,15 @@ static int __init __reserved_mem_init_node(struct reserved_mem *rmem,
  * @uname: name of the reserved memory node
  * @base: base address of the reserved memory region
  * @size: size of the reserved memory region
+ * @dynamic: whether the region was dynamically allocated
  *
  * This function calls the region-specific initialization function for a
  * reserved memory region and saves all region-specific data to the
  * 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;
@@ -708,7 +711,8 @@ 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