Re: [Qemu-devel] [PATCH v2 2/2] memory: fix possible NULL pointer dereference

[Dima Stepanov <dimastep@yandex-team.ru>]

Ping. I believe i forgot to add the maintainer to CC.

+ pbonzini@redhat.com

Regards, Dima.

On Wed, Jun 13, 2018 at 11:19:55AM +0300, Dima Stepanov wrote:
> In the memory_region_do_invalidate_mmio_ptr() routine the section
> variable is intialized by the memory_region_find() call. The section.mr
> field can be set to NULL.
> 
> Add the check for NULL before trying to drop a section.
> 
> Signed-off-by: Dima Stepanov <dimastep@yandex-team.ru>
> ---
>  memory.c | 2 +-
>  1 file changed, 1 insertion(+), 1 deletion(-)
> 
> diff --git a/memory.c b/memory.c
> index 3212acc..bb45248 100644
> --- a/memory.c
> +++ b/memory.c
> @@ -2712,7 +2712,7 @@ static void memory_region_do_invalidate_mmio_ptr(CPUState *cpu,
>      /* Reset dirty so this doesn't happen later. */
>      cpu_physical_memory_test_and_clear_dirty(offset, size, 1);
>  
> -    if (section.mr != mr) {
> +    if (section.mr && (section.mr != mr)) {
>          /* memory_region_find add a ref on section.mr */
>          memory_region_unref(section.mr);
>          if (MMIO_INTERFACE(section.mr->owner)) {
> -- 
> 2.7.4
> 
>