Re: [dpdk-dev] [PATCH] eal: fix leak in shared lib mode detection

[Bruce Richardson <bruce.richardson@intel.com>]

On Thu, May 06, 2021 at 12:06:37PM +0200, David Marchand wrote:
> This is reported by our internal covscan:
> 
> 1. dpdk-20.11/lib/librte_eal/common/eal_common_options.c:508: alloc_fn:
> Storage is returned from allocation function "dlopen".
> 6. dpdk-20.11/lib/librte_eal/common/eal_common_options.c:508:
> leaked_storage: Failing to save or free storage allocated by
> "dlopen("librte_eal.so.21.0", 5)" leaks it.
> 
>  #   506|   	 * shared library is not already loaded i.e. it's
>  #   statically linked.)
>  #   507|   	 */
>  #   508|-> 	if (dlopen("librte_eal.so."ABI_VERSION, RTLD_LAZY |
>  #   RTLD_NOLOAD) != NULL &&
>  #   509|   			*default_solib_dir != '\0' &&
>  #   510|   			stat(default_solib_dir, &sb) == 0 &&
> 
> This leak is not an issue per se, but on the other hand, this is easy
> to fix and I prefer not having to waive this warning later.
> 
> Fixes: 06c7871dde01 ("eal: restrict default plugin path to shared lib mode")
> Cc: stable@dpdk.org
> 
> Signed-off-by: David Marchand <david.marchand@redhat.com>
> ---
>  lib/eal/common/eal_common_options.c | 6 +++++-
>  1 file changed, 5 insertions(+), 1 deletion(-)
> 
> diff --git a/lib/eal/common/eal_common_options.c b/lib/eal/common/eal_common_options.c
> index 97ab6e00fd..ff5861b5f3 100644
> --- a/lib/eal/common/eal_common_options.c
> +++ b/lib/eal/common/eal_common_options.c
> @@ -509,10 +509,14 @@ is_shared_build(void)
>  	}
>  
>  	while (len >= minlen) {
> +		void *handle;
> +
>  		/* check if we have this .so loaded, if so - shared build */
>  		RTE_LOG(DEBUG, EAL, "Checking presence of .so '%s'\n", soname);
> -		if (dlopen(soname, RTLD_LAZY | RTLD_NOLOAD) != NULL) {
> +		handle = dlopen(soname, RTLD_LAZY | RTLD_NOLOAD);
> +		if (handle != NULL) {
>  			RTE_LOG(INFO, EAL, "Detected shared linkage of DPDK\n");
> +			dlclose(handle);
>  			return 1;
>  		}
>  

Acked-by: Bruce Richardson <bruce.richardson@intel.com>

Since this is not really a leak, I'm not sure it needs backport, but no
harm in CC'ing stable and letting maintainers choose.