Re: [PATCH] tools/virtio: check mmap return value in vringh_test

["Michael S. Tsirkin" <mst@redhat.com>]

On Fri, Jun 05, 2026 at 10:14:45AM +0800, longlong yan wrote:
> In parallel_test(), the return values of mmap() for both host_map and
> guest_map are not checked against MAP_FAILED. If mmap() fails, the
> subsequent code will dereference the invalid pointer, leading to a
> segmentation fault.
> 
> Add MAP_FAILED checks after both mmap() calls, using err() to report
> the error and exit, consistent with the existing error handling style
> in this file (e.g., the open() call on line 149).
> 
> Fixes: 1515c5ce26ae("tools/virtio: add vring_test.")
> Signed-off-by: longlong yan <yanlonglong@kylinos.cn>
> ---
>  tools/virtio/vringh_test.c | 5 +++++
>  1 file changed, 5 insertions(+)
> 
> diff --git a/tools/virtio/vringh_test.c b/tools/virtio/vringh_test.c
> index b9591223437a..8cc5ca6c7cca 100644
> --- a/tools/virtio/vringh_test.c
> +++ b/tools/virtio/vringh_test.c
> @@ -159,7 +159,12 @@ static int parallel_test(u64 features,
>  
>  	/* Parent and child use separate addresses, to check our mapping logic! */
>  	host_map = mmap(NULL, mapsize, PROT_READ|PROT_WRITE, MAP_SHARED, fd, 0);
> +	if (host_map == MAP_FAILED)
> +		err(1, "mmap host_map");
> +	


trailing whitespace here.

>  	guest_map = mmap(NULL, mapsize, PROT_READ|PROT_WRITE, MAP_SHARED, fd, 0);
> +	if (guest_map == MAP_FAILED)
> +		err(1, "mmap guest_map");
>  
>  	pipe_ret = pipe(to_guest);
>  	assert(!pipe_ret);
> -- 
> 2.43.0