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

[Marek Szyprowski]

On 18.08.2026 11:24, Wandun Chen wrote:
> 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>
Acked-by: Marek Szyprowski <m.szyprowski@xxxxxxxxxxx>
> Link: https://protect2.fireeye.com/v1/url?k=37bb3269-68033acb-37bab926-000babff88b5-00648778f1201363&q=1&e=40542077-d5ad-41ca-88fd-1cf102a816c1&u=https%3A%2F%2Fsashiko.dev%2F%23%2Fmessage%2F20260806100605.2C2C01F000E9%2540smtp.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 {

Best regards
-- 
Marek Szyprowski, PhD
Samsung R&D Institute Poland