Re: [for-linus][PATCH 1/2] bootconfig: Fix to check the xbc_node is used before free it

[Vlastimil Babka]

On 9/14/21 16:48, Steven Rostedt wrote:
> From: Masami Hiramatsu <mhiramat@xxxxxxxxxx>
> 
> Fix to check the xbc_node is used before calling memblock_free()
> because passing NULL to phys_addr() will cause a panic.
> This will happen if user doesn't pass any bootconfig to the
> kernel, because kernel will call xbc_destroy_all() after
> booting.
> 
> Link: https://lkml.kernel.org/r/163149460533.291098.7342418455457691240.stgit@devnote2
> 
> Fixes: 40caa127f3c7 ("init: bootconfig: Remove all bootconfig data when the init memory is removed")
> Reported-by: kernel test robot <oliver.sang@xxxxxxxxx>
> Signed-off-by: Masami Hiramatsu <mhiramat@xxxxxxxxxx>
> Signed-off-by: Steven Rostedt (VMware) <rostedt@xxxxxxxxxxx>

Should have replied here.

Tested-by: Vlastimil Babka <vbabka@xxxxxxx>

details:
https://lore.kernel.org/all/61ab2d0c-3313-aaab-514c-e15b7aa054a0@xxxxxxx/

> ---
>  lib/bootconfig.c | 3 ++-
>  1 file changed, 2 insertions(+), 1 deletion(-)
> 
> diff --git a/lib/bootconfig.c b/lib/bootconfig.c
> index f8419cff1147..4f8849706ef6 100644
> --- a/lib/bootconfig.c
> +++ b/lib/bootconfig.c
> @@ -792,7 +792,8 @@ void __init xbc_destroy_all(void)
>  	xbc_data = NULL;
>  	xbc_data_size = 0;
>  	xbc_node_num = 0;
> -	memblock_free(__pa(xbc_nodes), sizeof(struct xbc_node) * XBC_NODE_MAX);
> +	if (xbc_nodes)
> +		memblock_free(__pa(xbc_nodes), sizeof(struct xbc_node) * XBC_NODE_MAX);
>  	xbc_nodes = NULL;
>  	brace_index = 0;
>  }
>