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ctdb->methods becomes NULL when we shutdown the transport.

If we shutdown the transport   and CTDB later decides to send a command out
for queueing, the call to ctdb->methods->allocate_pkt() will SEGV.

This could trigger for example when we are in the process of shuttind down CTDBD and have already shutdown the transport but we are still waiting for the
"shutdown" eventscripts to finish.
If the event scripts now take much much longer to execute for some reason, this
race condition becomes much more probable.

Decorate all dereferencing of ctdb->methods->    with a check that ctdb->menthods is non-NULL

(This used to be ctdb commit c4c2c53918da6fb566d6e9cbd6b02e61ae2921e7)
This commit is contained in:
Ronnie Sahlberg 2008-05-11 14:28:33 +10:00
parent ac9b9679bb
commit adf40341a7
5 changed files with 43 additions and 4 deletions

View File

@ -276,7 +276,9 @@ static int32_t ctdb_control_dispatch(struct ctdb_context *ctdb,
ctdb_stop_keepalive(ctdb);
ctdb_stop_monitoring(ctdb);
ctdb_release_all_ips(ctdb);
ctdb->methods->shutdown(ctdb);
if (ctdb->methods != NULL) {
ctdb->methods->shutdown(ctdb);
}
ctdb_event_script(ctdb, "shutdown");
DEBUG(DEBUG_NOTICE,("Received SHUTDOWN command. Stopping CTDB daemon.\n"));
exit(0);

View File

@ -71,6 +71,11 @@ static void print_exit_message(void)
/* called when the "startup" event script has finished */
static void ctdb_start_transport(struct ctdb_context *ctdb)
{
if (ctdb->methods == NULL) {
DEBUG(DEBUG_ALERT,(__location__ " startup event finished but transport is DOWN.\n"));
ctdb_fatal(ctdb, "transport is not initialized but startup completed");
}
/* start the transport running */
if (ctdb->methods->start(ctdb) != 0) {
DEBUG(DEBUG_ALERT,("transport failed to start!\n"));
@ -689,6 +694,11 @@ int ctdb_start_daemon(struct ctdb_context *ctdb, bool do_fork)
return -1;
}
if (ctdb->methods == NULL) {
DEBUG(DEBUG_ALERT,(__location__ " Can not initialize transport. ctdb->methods is NULL\n"));
ctdb_fatal(ctdb, "transport is unavailable. can not initialize.");
}
/* initialise the transport */
if (ctdb->methods->initialise(ctdb) != 0) {
ctdb_fatal(ctdb, "transport failed to initialise");
@ -743,6 +753,12 @@ struct ctdb_req_header *_ctdb_transport_allocate(struct ctdb_context *ctdb,
length = MAX(length, slength);
size = (length+(CTDB_DS_ALIGNMENT-1)) & ~(CTDB_DS_ALIGNMENT-1);
if (ctdb->methods == NULL) {
DEBUG(DEBUG_ERR,(__location__ " Unable to allocate transport packet for operation %u of length %u. Transport is DOWN.\n",
operation, (unsigned)length));
return NULL;
}
hdr = (struct ctdb_req_header *)ctdb->methods->allocate_pkt(mem_ctx, size);
if (hdr == NULL) {
DEBUG(DEBUG_ERR,("Unable to allocate transport packet for operation %u of length %u\n",

View File

@ -180,7 +180,9 @@ ctdb_reload_nodes_event(struct event_context *ev, struct timed_event *te,
int ctdb_tcp_init(struct ctdb_context *);
/* shut down the transport */
ctdb->methods->shutdown(ctdb);
if (ctdb->methods != NULL) {
ctdb->methods->shutdown(ctdb);
}
/* start the transport again */
ctdb_load_nodes_file(ctdb);
@ -189,6 +191,11 @@ ctdb_reload_nodes_event(struct event_context *ev, struct timed_event *te,
DEBUG(DEBUG_CRIT, (__location__ " Failed to init TCP\n"));
exit(1);
}
if (ctdb->methods == NULL) {
DEBUG(DEBUG_ALERT,(__location__ " Can not restart transport. ctdb->methods==NULL\n"));
ctdb_fatal(ctdb, "can not reinitialize transport.");
}
ctdb->methods->initialise(ctdb);
ctdb->methods->start(ctdb);

View File

@ -2790,7 +2790,9 @@ static void ctdb_check_recd(struct event_context *ev, struct timed_event *te,
ctdb_stop_keepalive(ctdb);
ctdb_stop_monitoring(ctdb);
ctdb_release_all_ips(ctdb);
ctdb->methods->shutdown(ctdb);
if (ctdb->methods != NULL) {
ctdb->methods->shutdown(ctdb);
}
ctdb_event_script(ctdb, "shutdown");
exit(10);
@ -2831,7 +2833,9 @@ int ctdb_start_recoverd(struct ctdb_context *ctdb)
close(fd[1]);
/* shutdown the transport */
ctdb->methods->shutdown(ctdb);
if (ctdb->methods) {
ctdb->methods->shutdown(ctdb);
}
/* get a new event context */
talloc_free(ctdb->ev);

View File

@ -345,6 +345,11 @@ void ctdb_node_dead(struct ctdb_node *node)
node->ctdb->name, node->name, node->ctdb->num_connected));
ctdb_daemon_cancel_controls(node->ctdb, node);
if (node->ctdb->methods == NULL) {
DEBUG(DEBUG_ALERT,(__location__ " Can not restart transport. ctdb->methods==NULL\n"));
ctdb_fatal(node->ctdb, "can not restart transport.");
}
node->ctdb->methods->restart(node);
}
@ -484,6 +489,11 @@ void ctdb_queue_packet(struct ctdb_context *ctdb, struct ctdb_req_header *hdr)
if (hdr->destnode == ctdb->pnn) {
ctdb_defer_packet(ctdb, hdr);
} else {
if (ctdb->methods == NULL) {
DEBUG(DEBUG_ALERT, (__location__ " Can not queue packet. Transport is DOWN\n"));
return;
}
node->tx_cnt++;
if (ctdb->methods->queue_pkt(node, (uint8_t *)hdr, hdr->length) != 0) {
ctdb_fatal(ctdb, "Unable to queue packet\n");