Race condition in Oracle C Interface?

I am trying to use Oracle in a multithreaded application that creates and destroys multiple database connections. It seems to have tickled a bug in Oracle, though, because the application hangs up deep in Oracle. I simplified the application into the trivial C program appended below, which on my system locks up about half of the time. It just opens up two database connections and some associated structures and then closes them. I don't think there is a problem with code, but if you are sceptical just take a look; it is quite trivial.

Has anybody seen this problem? Does anyone know a workaround?

I am running Oracle 8.1.6.1 under Linux/Intel with kernel version 2.2.14. The program locks up within OCIServerDetach and has to be kill -6'ed or stronger. Only the client seems to lock up; the server seems unaffected.

Thanks,
Michael

--
Michael Haggerty
mhagger_at_alum.mit.edu

/* ==================== main.c ======================== */

/* compile with:

    gcc -I/ora8/m01/app/oracle/product/8.1.6/rdbms/demo -I/ora8/m01/app/oracle/product/8.1.6/network/public -I/ora8/m01/app/oracle/product/8.1.6/plsql/public -I/ora8/m01/app/oracle/product/8.1.6/rdbms/public -DORACLE8i -g -o main -L/ora8/m01/app/oracle/product/8.1.6/lib/ -lclntsh -Wl,-rpath,/ora8/m01/app/oracle/product/8.1.6/lib ./main.c

*/

#include <assert.h>
#include <stdio.h>
#include <string.h>
#include <malloc.h>
#include <oci.h>


typedef struct {
	OCIEnv		*envhp;			/* Environment handle 	*/
	OCIError	*errhp;			/* Error handle		*/
	OCIServer	*srvhp;			/* Server handle	*/
	OCISession	*usrhp;			/* User handle		*/
	OCISvcCtx	*svchp;			/* Service Context	*/
} ServerContext;


ServerContext *Connect(char *user, char *password, char *database) {
	ServerContext *sc;
	int	userlen;
	int	passwordlen;
	int	databaselen;
	sword	status;
	sword	credentials = OCI_CRED_RDBMS;

        userlen = strlen(user);
        passwordlen = strlen(password);
        databaselen = strlen(database);

        sc = (ServerContext *)malloc(sizeof(ServerContext));

	sc->envhp = NULL;
	sc->errhp = NULL;
	sc->svchp = NULL;
	sc->srvhp = NULL;
	sc->usrhp = NULL;

	status = OCIEnvCreate(&sc->envhp, OCI_THREADED, NULL, NULL, NULL, NULL,
                              0, NULL);
	assert(status == OCI_SUCCESS);



	/* Allocate the error handle */

	status = OCIHandleAlloc(sc->envhp, (dvoid **)&sc->errhp,
                                OCI_HTYPE_ERROR, 0, NULL);
	assert(status == OCI_SUCCESS);



	/* Allocate the server handle */

	status = OCIHandleAlloc(sc->envhp, (dvoid **) &sc->srvhp,
                                OCI_HTYPE_SERVER, 0, NULL);
	assert(status == OCI_SUCCESS);



	/* Connect to database */

	status = OCIServerAttach(sc->srvhp, sc->errhp, database, databaselen,
                                 OCI_DEFAULT);
	assert(status == OCI_SUCCESS);



	/* Allocate a service context */

	status = OCIHandleAlloc(sc->envhp, (dvoid **) &sc->svchp,
                                OCI_HTYPE_SVCCTX, 0, NULL);
	assert(status == OCI_SUCCESS);



	/* Attach the server to the service context */

	status = OCIAttrSet(sc->svchp, OCI_HTYPE_SVCCTX, (dvoid *) sc->srvhp,
                            (ub4) 0, OCI_ATTR_SERVER, sc->errhp);
	assert(status == OCI_SUCCESS);



	/* Allocate a session */

	status = OCIHandleAlloc(sc->envhp, (dvoid **) &sc->usrhp,
                                OCI_HTYPE_SESSION, 0, NULL);
	assert(status == OCI_SUCCESS);



	/* Were credentials provided? if so, set them in the session */

        status = OCIAttrSet(sc->usrhp, OCI_HTYPE_SESSION,
                            (dvoid *) user, (ub4) userlen,
                            OCI_ATTR_USERNAME, sc->errhp);
        assert(status == OCI_SUCCESS);

        status = OCIAttrSet(sc->usrhp, OCI_HTYPE_SESSION,
                            (dvoid *) password, (ub4) passwordlen,
                            OCI_ATTR_PASSWORD, sc->errhp);
        assert(status == OCI_SUCCESS);
	


	/* Now begin the session */

	status = OCISessionBegin(sc->svchp, sc->errhp, sc->usrhp,
                                 credentials, OCI_DEFAULT);
	assert(status == OCI_SUCCESS);



	/* Now attach the session to the service context */

	status = OCIAttrSet(sc->svchp, OCI_HTYPE_SVCCTX,
                            sc->usrhp, 0, OCI_ATTR_SESSION, sc->errhp);
	assert(status == OCI_SUCCESS);

	return sc;
}

/*
** ServerContext_dealloc
**
** Called when a server context goes out of scope; hang up the connection
** to the database!
*/

void ServerContext_dealloc(ServerContext *self) {
	sword status;



	/* End the session */

	assert(self->svchp);
        status = OCISessionEnd(self->svchp, self->errhp, self->usrhp,
                               OCI_DEFAULT);
        assert(status == OCI_SUCCESS);



	/* Disconnect from the server */

	assert(self->srvhp);
        status = OCIServerDetach(self->srvhp, self->errhp, OCI_DEFAULT);
        assert(status == OCI_SUCCESS);



	/* Deallocate the session handle */

        assert(self->usrhp);
        status = OCIHandleFree(self->usrhp, OCI_HTYPE_SESSION);
        assert(status == OCI_SUCCESS);



	/* Deallocate the server handle */

        assert(self->srvhp);
        status = OCIHandleFree(self->srvhp, OCI_HTYPE_SERVER);
        assert(status == OCI_SUCCESS);



	/* Deallocate the service context handle */

	assert(self->svchp);
        status = OCIHandleFree(self->svchp, OCI_HTYPE_SVCCTX);
        assert(status == OCI_SUCCESS);



	/* Deallocate the error handle */

        assert(self->errhp);
        status = OCIHandleFree(self->errhp, OCI_HTYPE_ERROR);
        assert(status == OCI_SUCCESS);



	/* Deallocate the environment handle */

        assert(self->envhp);
        status = OCIHandleFree(self->envhp, OCI_HTYPE_ENV);
        assert(status == OCI_SUCCESS);

        free(self);
}

int main(int argc, char *argv[]) {
    char *user;
    char *password;
    char *database;
    ServerContext *db1;
    ServerContext *db2;
    assert(argc == 4);
    user = argv[1];
    password = argv[2];
    database = argv[3];
    db1 = Connect(user, password, database);
    db2 = Connect(user, password, database);
    fprintf(stderr, "Deleting db2.\n");