Re: [Virtio-fs] [PATCH 2/5] virtiofsd: fix memory leak on lo.source

["Dr. David Alan Gilbert" <dgilbert@redhat.com>]

* Liu Bo (bo.liu@linux.alibaba.com) wrote:
> valgrind reported that lo.source is leaked on quiting, but it was defined
> as (const char*) as it may point to a const string "/".
> 
> This adds a check to free the allocated memory only.
> 
> Signed-off-by: Liu Bo <bo.liu@linux.alibaba.com>
> ---
>  contrib/virtiofsd/passthrough_ll.c | 7 ++++++-
>  1 file changed, 6 insertions(+), 1 deletion(-)
> 
> diff --git a/contrib/virtiofsd/passthrough_ll.c b/contrib/virtiofsd/passthrough_ll.c
> index b58708f..f348b16 100644
> --- a/contrib/virtiofsd/passthrough_ll.c
> +++ b/contrib/virtiofsd/passthrough_ll.c
> @@ -2217,6 +2217,7 @@ int main(int argc, char *argv[])
>  	};
>  	struct lo_map_elem *root_elem;
>  	int ret = -1;
> +        bool free_source = false;
>  
>  	/* Don't mask creation mode, kernel already did that */
>  	umask(0);
> @@ -2269,9 +2270,10 @@ int main(int argc, char *argv[])
>  			err(1, "failed to stat source (\"%s\")", lo.source);
>  		if (!S_ISDIR(stat.st_mode))
>  			errx(1, "source is not a directory");
> -
> +                free_source = true;
>  	} else {
>  		lo.source = "/";
> +                free_source = false;

An easier way is just to do    lo.source = strdup("/")
and then we don't need the flag.

>  	}
>  	lo.root.is_symlink = false;
>  	if (!lo.timeout_set) {
> @@ -2333,5 +2335,8 @@ err_out1:
>  	if (lo.root.fd >= 0)
>  		close(lo.root.fd);
>  
> +        if (free_source)
> +                free((char *)lo.source);
> +
>  	return ret ? 1 : 0;
>  }
> -- 
> 1.8.3.1
> 
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--
Dr. David Alan Gilbert / dgilbert@redhat.com / Manchester, UK