I've noticed when running libvirtd in the session mode that whenever I start a virtual machine the following error is printed into logs: error : cannot execute binary /usr/bin/slirp-helper: No such file or directory The error message is produced in qemuSlirpNewForHelper() which does attempt to be a NO-OP if the helper doesn't exist by checking if its path is NULL, but that's not usually the case because in the default config (in virQEMUDriverConfigNew()) its path is initialized to QEMU_SLIRP_HELPER. And while it is true that during configure we try to get the actual path of the helper we fallback to the path above if not found. Fix the check so that the function checks whether the helper exists and is executable. Signed-off-by: Michal Privoznik <mprivozn(a)redhat.com&gt; --- src/qemu/qemu_slirp.c | 3 ++- 1 file changed, 2 insertions(+), 1 deletion(-) diff --git a/src/qemu/qemu_slirp.c b/src/qemu/qemu_slirp.c index d2e4ed79be..4e5ab12727 100644 --- a/src/qemu/qemu_slirp.c +++ b/src/qemu/qemu_slirp.c @@ -101,7 +101,8 @@ qemuSlirpNewForHelper(const char *helper) virJSONValuePtr featuresJSON; size_t i, nfeatures; - if (!helper) + if (!helper || + !virFileIsExecutable(helper)) return NULL; slirp = qemuSlirpNew(); -- 2.26.2