Hi. I am using libvirt for some time and I have found the following problem. When I try opening two connections with the same credentials to the same host but using different transport(TCP and TLS) I get the following error when trying to free the TLS one: "*** Error in `./test': double free or corruption (!prev): 0x00000000014a7a60 *** Aborted (core dumped)" Example code: #include <stdio.h> #include <stdlib.h> #include <string.h> #include <libvirt/libvirt.h> struct CredentialsPack { const char* username; const char* password; }; struct CredentialsPack* newCredentialsPack(const char* username, const char* password) { struct CredentialsPack* ptr = malloc(sizeof(struct CredentialsPack)); ptr->username = username; ptr->password = password; return ptr; } static int authCredTypes[] = { VIR_CRED_AUTHNAME, VIR_CRED_PASSPHRASE, }; static int authCb(virConnectCredentialPtr cred, unsigned int ncred, void* cbdata) { struct CredentialsPack* inputCreds = (struct CredentialsPack*) cbdata; int i; for (i = 0; i < ncred; ++i) { if (cred[i].type == VIR_CRED_AUTHNAME) { cred[i].result = strdup(inputCreds->username); if (cred[i].result == NULL) { return -1; } cred[i].resultlen = strlen(cred[i].result); } else if (cred[i].type == VIR_CRED_PASSPHRASE) { cred[i].result = strdup(inputCreds->password); if (cred[i].result == NULL) { return -1; } cred[i].resultlen = strlen(cred[i].result); } } return 0; } int main(){ struct CredentialsPack* credentials = newCredentialsPack("user", "pass"); virConnectAuth auth; auth.credtype = authCredTypes; auth.ncredtype = sizeof(authCredTypes) / sizeof(int); auth.cb = authCb; auth.cbdata = credentials; virConnectPtr conn; conn = virConnectOpenAuth("qemu+tcp://host1/system", &auth, 0); struct CredentialsPack* credentials2 = newCredentialsPack("user", "pass"); virConnectAuth auth2; auth2.credtype = authCredTypes; auth2.ncredtype = sizeof(authCredTypes) / sizeof(int); auth2.cb = authCb; auth2.cbdata = credentials2; virConnectPtr conn2; conn2 = virConnectOpenAuth("qemu://host1/system", &auth2, 0); // virConnectClose(conn); // this does not change the behaviour virConnectClose(conn2); // here the error occurs } If I try to close "conn" then everything works until I try to close "conn2". I can even invoke virConnectListAllDomains using "conn2" and use the domain pointers when "conn" is closed. The problem is when I try to close "conn2". The platform running this code is Ubuntu 14.04. The version of libvirt is 1.2.2 (default configuration). The certificate of the CA which signed the server certificate is under /etc/pki/CA/cacert.pem The target machine is RHEL 6.5. The version of libvirt is 0.10.2. It is configured this way: listen_tls = 1 listen_tcp = 1 auth_tcp = sasl auth_tls = sasl tls_no_verify_certificate = 1 Everything else is set to default. The certificate of the CA which signed the server certificate is under /etc/pki/CA/cacert.pem The user "user" is added to the DB( using $ saslpasswd2 -a libvirt user). I can successfully execute the following on the command line using the "user"/"pass" credentials: virsh -c qemu://host1/system list virsh -c qemu+tcp://host1/system list I hope this will be useful. Thank you.