Re: [PATCH 2/9] tests/test_vhost_user_bridge: skip when running ASAN

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

does not look like this patch skips any tests?

On Sun, Sep 06, 2026 at 12:53:34PM +0400, Marc-André Lureau wrote:
> Running vhost-user-bridge built with ASAN with stdbuf dies:
> ==2431898==ASan runtime does not come first in initial library list; you
> should either link runtime to your application or manually preload it
> with LD_PRELOAD.

so it dies but why? judging by below because of stdbuf?

pls describe the fix not just the problem.

> Signed-off-by: Marc-André Lureau <marcandre.lureau@redhat.com>
> ---
>  tests/functional/x86_64/test_vhost_user_bridge.py | 13 +++++++++++++
>  1 file changed, 13 insertions(+)
> 
> diff --git a/tests/functional/x86_64/test_vhost_user_bridge.py b/tests/functional/x86_64/test_vhost_user_bridge.py
> index c36c62542053..5fedf61c5e72 100755
> --- a/tests/functional/x86_64/test_vhost_user_bridge.py
> +++ b/tests/functional/x86_64/test_vhost_user_bridge.py
> @@ -73,12 +73,25 @@ def configure_vm(self, ud_socket_path, lport, rport, hostfwd_port, tftpdir):
>              "-netdev",   "hubport,id=hub1,hubid=0,netdev=user0"
>          )
>  
> +    @staticmethod
> +    def _is_asan_linked(binary_path):
> +        try:
> +            output = subprocess.check_output(
> +                ["ldd", binary_path], stderr=subprocess.DEVNULL, text=True)
> +            return "libasan" in output


this is quite a hack

> +        except (subprocess.CalledProcessError, FileNotFoundError):
> +            return False
> +
>      def assemble_vubr_args(self, vubr_path, ud_socket_path, lport, rport):
>          vubr_args = []
>  
>          if (stdbuf_path := which("stdbuf")) is None:
>              self.log.info("Could not find stdbuf: vhost-user-bridge "
>                            "log lines may appear out of order")
> +        elif self._is_asan_linked(vubr_path):
> +            self.log.info("vhost-user-bridge is ASan-linked: skipping "
> +                          "stdbuf to avoid LD_PRELOAD conflict, "
> +                          "log lines may appear out of order")
>          else:
>              vubr_args += [stdbuf_path, "-o0", "-e0"]
>  


maybe just avoid stdbuf completely.
i don't remember why we use it, but it looks like merely to
disable buffering for stdout?

If so:

setvbuf(stdout, NULL, _IONBF, 0);

will do just that with no asan issues.


> -- 
> 2.55.0.543.g5ebe2ebe4ea8
> 
>