Relay threads keep using tx upon shutdown, which leads to occasional
segmentation faults and assertion fails (e.g. in replication test
suite).
Fix this by implementing replication_shutdown and relay_halt functions.
replication_shutdown calls relay_halt to stop every relay thread that is
using tx.
Closes #3485
---
FYI, I couldn't come up with a test case for this patch. My best effort
was to run replication test suite multiple times and make sure that there
were less crashes.
https://github.com/tarantool/tarantool/issues/3485
https://github.com/tarantool/tarantool/compare/sergepetrenko/gh-3485-replication-shutdown
src/box/box.cc | 2 +-
src/box/relay.cc | 60 ++++++++++++++++++++++++++++++++++++++++++++++++++
src/box/relay.h | 10 +++++++++
src/box/replication.cc | 30 +++++++++++++++++++++++++
src/box/replication.h | 6 +++++
src/main.cc | 1 +
6 files changed, 108 insertions(+), 1 deletion(-)
diff --git a/src/box/box.cc b/src/box/box.cc
index ae4959d6f..f212c0fa8 100644
--- a/src/box/box.cc
+++ b/src/box/box.cc
@@ -1597,9 +1597,9 @@ box_free(void)
* initialized
*/
if (is_box_configured) {
+ replication_shutdown();
#if 0
session_free();
- replication_free();
user_cache_free();
schema_free();
module_free();
diff --git a/src/box/relay.cc b/src/box/relay.cc
index 4cacbc840..0a81ac5db 100644
--- a/src/box/relay.cc
+++ b/src/box/relay.cc
@@ -82,10 +82,22 @@ struct relay_gc_msg {
struct vclock vclock;
};
+/**
+ * Cbus message sent by tx thread to stop relay on shutdown.
+ */
+struct relay_halt_msg {
+ /** Parent. */
+ struct cmsg msg;
+ /** Relay instance. */
+ struct relay *relay;
+};
+
/** State of a replication relay. */
struct relay {
/** The thread in which we relay data to the replica. */
struct cord cord;
+ /** The main fiber in cord to be canceled upon relay halt. */
+ struct fiber *main_fiber;
/** Replica connection */
struct ev_io io;
/** Request sync */
@@ -120,6 +132,11 @@ struct relay {
struct cpipe tx_pipe;
/** A pipe from 'tx' thread to 'relay' */
struct cpipe relay_pipe;
+ /**
+ * A flag indicating that we executed relay_subscribe_f and
+ * have tx_pipe and relay_pipe ready.
+ */
+ bool tx_in_use;
/** Status message */
struct relay_status_msg status_msg;
/**
@@ -152,6 +169,12 @@ relay_get_state(const struct relay *relay)
return relay->state;
}
+bool
+relay_uses_tx(const struct relay *relay)
+{
+ return relay->tx_in_use;
+}
+
const struct vclock *
relay_vclock(const struct relay *relay)
{
@@ -198,6 +221,40 @@ relay_start(struct relay *relay, int fd, uint64_t sync,
relay->state = RELAY_FOLLOW;
}
+static void
+relay_main_fiber_halt(struct cmsg *msg)
+{
+ struct relay_halt_msg *m = (struct relay_halt_msg *)msg;
+ struct relay *relay = m->relay;
+
+ assert(relay->main_fiber != NULL);
+ fiber_cancel(relay->main_fiber);
+ relay->main_fiber = NULL;
+
+ free(m);
+}
+
+void
+relay_halt(struct relay *relay)
+{
+ assert(relay->state == RELAY_FOLLOW);
+
+ static const struct cmsg_hop route[] ={
+ {relay_main_fiber_halt, NULL}
+ };
+ struct relay_halt_msg *m = (struct relay_halt_msg *)malloc(sizeof(*m));
+ if (m == NULL) {
+ /*
+ * Out of memory during shutdown. Do nothing.
+ */
+ say_warn("failed to allocate relay halt message");
+ return;
+ }
+ cmsg_init(&m->msg, route);
+ m->relay = relay;
+ cpipe_push(&relay->relay_pipe, &m->msg);
+}
+
static void
relay_stop(struct relay *relay)
{
@@ -468,6 +525,8 @@ relay_subscribe_f(va_list ap)
fiber_schedule_cb, fiber());
cbus_pair("tx", cord_name(cord()), &relay->tx_pipe, &relay->relay_pipe,
NULL, NULL, cbus_process);
+ relay->main_fiber = fiber();
+ relay->tx_in_use = true;
/* Setup garbage collection trigger. */
struct trigger on_close_log = {
RLIST_LINK_INITIALIZER, relay_on_close_log_f, relay, NULL
@@ -545,6 +604,7 @@ relay_subscribe_f(va_list ap)
cbus_unpair(&relay->tx_pipe, &relay->relay_pipe,
NULL, NULL, cbus_process);
cbus_endpoint_destroy(&relay->endpoint, cbus_process);
+ relay->tx_in_use = false;
if (!diag_is_empty(&relay->diag)) {
/* An error has occurred while reading ACKs of xlog. */
diag_move(&relay->diag, diag_get());
diff --git a/src/box/relay.h b/src/box/relay.h
index 2988e6b0d..deaba34d4 100644
--- a/src/box/relay.h
+++ b/src/box/relay.h
@@ -61,6 +61,10 @@ enum relay_state {
struct relay *
relay_new(struct replica *replica);
+/** Stop a running relay.. Called on shutdown. */
+void
+relay_halt(struct relay *relay);
+
/** Destroy and delete the relay */
void
relay_delete(struct relay *relay);
@@ -73,6 +77,12 @@ relay_get_diag(struct relay *relay);
enum relay_state
relay_get_state(const struct relay *relay);
+/**
+ * Return whether relay_subscribe_f was already started
+ * and pipes between tx and relay were created.
+ */
+bool
+relay_uses_tx(const struct relay *relay);
/**
* Returns relay's vclock
* @param relay relay
diff --git a/src/box/replication.cc b/src/box/replication.cc
index 48956d2ed..9b4968777 100644
--- a/src/box/replication.cc
+++ b/src/box/replication.cc
@@ -398,6 +398,36 @@ replica_on_applier_state_f(struct trigger *trigger, void
*event)
fiber_cond_signal(&replicaset.applier.cond);
}
+void
+replication_shutdown()
+{
+ struct replica *replica, *next;
+
+ replica_hash_foreach_safe(&replicaset.hash, replica, next) {
+ if (replica->id == instance_id)
+ continue;
+ if (replica->applier != NULL) {
+ replica_clear_applier(replica);
+ /*
+ * We're exiting, so control won't be passed
+ * to appliers and we don't need to stop them.
+ */
+ }
+ if (replica->id != REPLICA_ID_NIL) {
+ if (relay_get_state(replica->relay) == RELAY_FOLLOW &&
+ relay_uses_tx(replica->relay)) {
+ replica->id = REPLICA_ID_NIL;
+ relay_halt(replica->relay);
+ }
+ } else {
+ replica_hash_remove(&replicaset.hash, replica);
+ replica_delete(replica);
+ }
+ }
+
+ replication_free();
+}
+
/**
* Update the replica set with new "applier" objects
* upon reconfiguration of box.cfg.replication.
diff --git a/src/box/replication.h b/src/box/replication.h
index e8b391af2..08f9df258 100644
--- a/src/box/replication.h
+++ b/src/box/replication.h
@@ -333,6 +333,12 @@ replica_on_relay_stop(struct replica *replica);
void
replica_check_id(uint32_t replica_id);
+/*
+ * Stop replication and delete all replicas and replicaset.
+ */
+void
+replication_shutdown();
+
/**
* Register the universally unique identifier of a remote replica and
* a matching replica-set-local identifier in the _cluster registry.
diff --git a/src/main.cc b/src/main.cc
index a36a2b0d0..9cb3243b6 100644
--- a/src/main.cc
+++ b/src/main.cc
@@ -76,6 +76,7 @@
#include "box/lua/init.h" /* box_lua_init() */
#include "box/session.h"
#include "systemd.h"
+#include "box/replication.h" /* replication_shutdown() */
static pid_t master_pid = getpid();
static struct pidfh *pid_file_handle;
--
2.15.2 (Apple Git-101.1)
