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authorKotresh HR <khiremat@redhat.com>2016-03-07 11:45:07 +0530
committerJeff Darcy <jdarcy@redhat.com>2016-07-22 08:12:52 -0700
commit637ce9e2e27e9f598a4a6c5a04cd339efaa62076 (patch)
tree06c2761aba0ca5572c014debd40d10f720e14e40 /rpc
parentb76ac27f6fe2a183c350f236e3da16f38189e4a8 (diff)
changelog/rpc: Fix rpc_clnt_t mem leaks
PROBLEM: 1. Freeing up rpc_clnt object might lead to crashes. Well, it was not a necessity to free rpc-clnt object till now because all the existing use cases needs to reconnect back on disconnects. Hence timer code was not taking ref on rpc-clnt object. Glusterd had some use-cases that led to crash due to ping-timer and they fixed only those code paths that involve ping-timer. Now, since changelog has an use-case where rpc-clnt need to be freed up, we need to fix timer code to take refs 2. In changelog, because of issue 1, only mydata was being freed which is incorrect. And there are races where rpc-clnt object would access the freed mydata which would lead to crashes. Since changelog xlator resides on brick side and is long living process, if multiple libgfchangelog consumers register to changelog and disconnect/reconnect mulitple times, it would result in leak of 'rpc-clnt' object for every connect/disconnect. SOLUTION: 1. Handle ref/unref of 'rpc_clnt' structure in timer functions properly. 2. In changelog, unref 'rpc_clnt' in RPC_CLNT_DISCONNECT after disabling timers and free mydata on RPC_CLNT_DESTROY. RPC SETUP IN CHANGELOG: 1. changelog xlator initiates rpc server say 'changelog_rpc_server' 2. libgfchangelog initiates one rpc server say 'libgfchangelog_rpc_server' 3. libgfchangelog initiates rpc client and connects to 'changelog_rpc_server' 4. In return changelog_rpc_server initiates a rpc client and connects back to 'libgfchangelog_rpc_server' REF/UNREF HANDLING IN TIMER FUNCTIONS: Let's say rpc clnt refcount = 1 1. Take the ref before reigstering callback to timer queue >>>> rpc_clnt_ref (say ref count becomes = 2) 2. Register a callback to timer say 'callback1' 3. If register fails: >>>> rpc_clnt_unref (ref count = 1) 4. On timer expiration, 'callback1' gets called. So unref rpc clnt at the end in 'callback1'. This is corresponding to ref taken in step 1 >>>> rpc_clnt_unref (ref count = 1) 5. The cycle from step-1 to step-4 continues....until timer cancel event happens 6. timer cancel of say 'callback1' If timer cancel fails: Do nothing, Step-4 would have unrefd If timer cancel succeeds: >>>> rpc_clnt_unref (ref count = 1) Change-Id: I91389bc511b8b1a17824941970ee8d2c29a74a09 BUG: 1316178 Signed-off-by: Kotresh HR <khiremat@redhat.com> Reviewed-on: http://review.gluster.org/13658 Smoke: Gluster Build System <jenkins@build.gluster.org> NetBSD-regression: NetBSD Build System <jenkins@build.gluster.org> CentOS-regression: Gluster Build System <jenkins@build.gluster.org> Reviewed-by: Raghavendra G <rgowdapp@redhat.com>
Diffstat (limited to 'rpc')
-rw-r--r--rpc/rpc-lib/src/rpc-clnt.c104
-rw-r--r--rpc/rpc-lib/src/rpc-clnt.h1
2 files changed, 99 insertions, 6 deletions
diff --git a/rpc/rpc-lib/src/rpc-clnt.c b/rpc/rpc-lib/src/rpc-clnt.c
index 27e3940..a9e43eb 100644
--- a/rpc/rpc-lib/src/rpc-clnt.c
+++ b/rpc/rpc-lib/src/rpc-clnt.c
@@ -121,6 +121,7 @@ call_bail (void *data)
struct timespec timeout = {0,};
struct iovec iov = {0,};
char peerid[UNIX_PATH_MAX] = {0};
+ gf_boolean_t need_unref = _gf_false;
GF_VALIDATE_OR_GOTO ("client", data, out);
@@ -153,6 +154,8 @@ call_bail (void *data)
timeout.tv_sec = 10;
timeout.tv_nsec = 0;
+ /* Ref rpc as it's added to timer event queue */
+ rpc_clnt_ref (clnt);
gf_timer_call_cancel (clnt->ctx, conn->timer);
conn->timer = gf_timer_call_after (clnt->ctx,
timeout,
@@ -163,6 +166,7 @@ call_bail (void *data)
gf_log (conn->name, GF_LOG_WARNING,
"Cannot create bailout timer for %s",
peerid);
+ need_unref = _gf_true;
}
}
@@ -205,6 +209,9 @@ call_bail (void *data)
mem_put (trav);
}
out:
+ rpc_clnt_unref (clnt);
+ if (need_unref)
+ rpc_clnt_unref (clnt);
return;
}
@@ -230,6 +237,7 @@ __save_frame (struct rpc_clnt *rpc_clnt, call_frame_t *frame,
if (conn->timer == NULL) {
timeout.tv_sec = 10;
timeout.tv_nsec = 0;
+ rpc_clnt_ref (rpc_clnt);
conn->timer = gf_timer_call_after (rpc_clnt->ctx,
timeout,
call_bail,
@@ -389,6 +397,7 @@ rpc_clnt_reconnect (void *conn_ptr)
struct timespec ts = {0, 0};
int32_t ret = 0;
struct rpc_clnt *clnt = NULL;
+ gf_boolean_t need_unref = _gf_false;
conn = conn_ptr;
clnt = conn->rpc_clnt;
@@ -413,10 +422,16 @@ rpc_clnt_reconnect (void *conn_ptr)
"attempting reconnect");
ret = rpc_transport_connect (trans,
conn->config.remote_port);
+ rpc_clnt_ref (clnt);
conn->reconnect =
gf_timer_call_after (clnt->ctx, ts,
rpc_clnt_reconnect,
conn);
+ if (!conn->reconnect) {
+ need_unref = _gf_true;
+ gf_log (conn->name, GF_LOG_ERROR,
+ "Error adding to timer event queue");
+ }
} else {
gf_log (conn->name, GF_LOG_TRACE,
"breaking reconnect chain");
@@ -424,6 +439,9 @@ rpc_clnt_reconnect (void *conn_ptr)
}
pthread_mutex_unlock (&conn->lock);
+ rpc_clnt_unref (clnt);
+ if (need_unref)
+ rpc_clnt_unref (clnt);
return;
}
@@ -463,6 +481,8 @@ int
rpc_clnt_reconnect_cleanup (rpc_clnt_connection_t *conn)
{
struct rpc_clnt *clnt = NULL;
+ int ret = 0;
+ gf_boolean_t reconnect_unref = _gf_false;
if (!conn) {
goto out;
@@ -474,13 +494,18 @@ rpc_clnt_reconnect_cleanup (rpc_clnt_connection_t *conn)
{
if (conn->reconnect) {
- gf_timer_call_cancel (clnt->ctx, conn->reconnect);
+ ret = gf_timer_call_cancel (clnt->ctx, conn->reconnect);
+ if (!ret)
+ reconnect_unref = _gf_true;
conn->reconnect = NULL;
}
}
pthread_mutex_unlock (&conn->lock);
+ if (reconnect_unref)
+ rpc_clnt_unref (clnt);
+
out:
return 0;
}
@@ -496,6 +521,8 @@ rpc_clnt_connection_cleanup (rpc_clnt_connection_t *conn)
struct saved_frames *saved_frames = NULL;
struct rpc_clnt *clnt = NULL;
int unref = 0;
+ int ret = 0;
+ gf_boolean_t timer_unref = _gf_false;
if (!conn) {
goto out;
@@ -511,7 +538,9 @@ rpc_clnt_connection_cleanup (rpc_clnt_connection_t *conn)
/* bailout logic cleanup */
if (conn->timer) {
- gf_timer_call_cancel (clnt->ctx, conn->timer);
+ ret = gf_timer_call_cancel (clnt->ctx, conn->timer);
+ if (!ret)
+ timer_unref = _gf_true;
conn->timer = NULL;
}
@@ -528,6 +557,9 @@ rpc_clnt_connection_cleanup (rpc_clnt_connection_t *conn)
if (unref)
rpc_clnt_unref (clnt);
+ if (timer_unref)
+ rpc_clnt_unref (clnt);
+
out:
return 0;
}
@@ -851,6 +883,7 @@ rpc_clnt_notify (rpc_transport_t *trans, void *mydata,
rpc_transport_pollin_t *pollin = NULL;
struct timespec ts = {0, };
void *clnt_mydata = NULL;
+ gf_boolean_t unref_clnt = _gf_false;
DECLARE_OLD_THIS;
conn = mydata;
@@ -875,10 +908,16 @@ rpc_clnt_notify (rpc_transport_t *trans, void *mydata,
ts.tv_sec = 10;
ts.tv_nsec = 0;
+ rpc_clnt_ref (clnt);
conn->reconnect =
gf_timer_call_after (clnt->ctx, ts,
rpc_clnt_reconnect,
conn);
+ if (conn->reconnect == NULL) {
+ gf_log (conn->name, GF_LOG_WARNING,
+ "Cannot create rpc_clnt_reconnect timer");
+ unref_clnt = _gf_true;
+ }
}
}
pthread_mutex_unlock (&conn->lock);
@@ -886,6 +925,9 @@ rpc_clnt_notify (rpc_transport_t *trans, void *mydata,
if (clnt->notifyfn)
ret = clnt->notifyfn (clnt, clnt->mydata,
RPC_CLNT_DISCONNECT, NULL);
+ if (unref_clnt)
+ rpc_clnt_ref (clnt);
+
break;
}
@@ -1135,6 +1177,10 @@ rpc_clnt_start (struct rpc_clnt *rpc)
rpc->disabled = 0;
}
pthread_mutex_unlock (&conn->lock);
+ /* Corresponding unref will be either on successful timer cancel or last
+ * rpc_clnt_reconnect fire event.
+ */
+ rpc_clnt_ref (rpc);
rpc_clnt_reconnect (conn);
return 0;
@@ -1512,6 +1558,7 @@ rpc_clnt_submit (struct rpc_clnt *rpc, rpc_clnt_prog_t *prog,
int proglen = 0;
char new_iobref = 0;
uint64_t callid = 0;
+ gf_boolean_t need_unref = _gf_false;
if (!rpc || !prog || !frame) {
goto out;
@@ -1596,6 +1643,14 @@ rpc_clnt_submit (struct rpc_clnt *rpc, rpc_clnt_prog_t *prog,
if ((ret >= 0) && frame) {
/* Save the frame in queue */
__save_frame (rpc, frame, rpcreq);
+
+ /* A ref on rpc-clnt object is taken while registering
+ * call_bail to timer in __save_frame. If it fails to
+ * register, it needs an unref and should happen outside
+ * conn->lock which otherwise leads to deadlocks */
+ if (conn->timer == NULL)
+ need_unref = _gf_true;
+
conn->msgcnt++;
gf_log ("rpc-clnt", GF_LOG_TRACE, "submitted request "
@@ -1607,6 +1662,9 @@ rpc_clnt_submit (struct rpc_clnt *rpc, rpc_clnt_prog_t *prog,
}
pthread_mutex_unlock (&conn->lock);
+ if (need_unref)
+ rpc_clnt_unref (rpc);
+
if (ret == -1) {
goto out;
}
@@ -1739,6 +1797,9 @@ rpc_clnt_disable (struct rpc_clnt *rpc)
rpc_clnt_connection_t *conn = NULL;
rpc_transport_t *trans = NULL;
int unref = 0;
+ int ret = 0;
+ gf_boolean_t timer_unref = _gf_false;
+ gf_boolean_t reconnect_unref = _gf_false;
if (!rpc) {
goto out;
@@ -1751,12 +1812,20 @@ rpc_clnt_disable (struct rpc_clnt *rpc)
rpc->disabled = 1;
if (conn->timer) {
- gf_timer_call_cancel (rpc->ctx, conn->timer);
+ ret = gf_timer_call_cancel (rpc->ctx, conn->timer);
+ /* If the event is not fired and it actually cancelled
+ * the timer, do the unref else registered call back
+ * function will take care of it.
+ */
+ if (!ret)
+ timer_unref = _gf_true;
conn->timer = NULL;
}
if (conn->reconnect) {
- gf_timer_call_cancel (rpc->ctx, conn->reconnect);
+ ret = gf_timer_call_cancel (rpc->ctx, conn->reconnect);
+ if (!ret)
+ reconnect_unref = _gf_true;
conn->reconnect = NULL;
}
conn->connected = 0;
@@ -1774,6 +1843,12 @@ rpc_clnt_disable (struct rpc_clnt *rpc)
if (unref)
rpc_clnt_unref (rpc);
+ if (timer_unref)
+ rpc_clnt_unref (rpc);
+
+ if (reconnect_unref)
+ rpc_clnt_unref (rpc);
+
out:
return;
}
@@ -1784,6 +1859,9 @@ rpc_clnt_disconnect (struct rpc_clnt *rpc)
rpc_clnt_connection_t *conn = NULL;
rpc_transport_t *trans = NULL;
int unref = 0;
+ int ret = 0;
+ gf_boolean_t timer_unref = _gf_false;
+ gf_boolean_t reconnect_unref = _gf_false;
if (!rpc)
goto out;
@@ -1794,12 +1872,20 @@ rpc_clnt_disconnect (struct rpc_clnt *rpc)
{
rpc->disabled = 1;
if (conn->timer) {
- gf_timer_call_cancel (rpc->ctx, conn->timer);
+ ret = gf_timer_call_cancel (rpc->ctx, conn->timer);
+ /* If the event is not fired and it actually cancelled
+ * the timer, do the unref else registered call back
+ * function will take care of unref.
+ */
+ if (!ret)
+ timer_unref = _gf_true;
conn->timer = NULL;
}
if (conn->reconnect) {
- gf_timer_call_cancel (rpc->ctx, conn->reconnect);
+ ret = gf_timer_call_cancel (rpc->ctx, conn->reconnect);
+ if (!ret)
+ reconnect_unref = _gf_true;
conn->reconnect = NULL;
}
conn->connected = 0;
@@ -1815,6 +1901,12 @@ rpc_clnt_disconnect (struct rpc_clnt *rpc)
if (unref)
rpc_clnt_unref (rpc);
+ if (timer_unref)
+ rpc_clnt_unref (rpc);
+
+ if (reconnect_unref)
+ rpc_clnt_unref (rpc);
+
out:
return;
}
diff --git a/rpc/rpc-lib/src/rpc-clnt.h b/rpc/rpc-lib/src/rpc-clnt.h
index 01caeb8..f84b4cb 100644
--- a/rpc/rpc-lib/src/rpc-clnt.h
+++ b/rpc/rpc-lib/src/rpc-clnt.h
@@ -231,6 +231,7 @@ struct rpc_clnt *
rpc_clnt_unref (struct rpc_clnt *rpc);
int rpc_clnt_connection_cleanup (rpc_clnt_connection_t *conn);
+int rpc_clnt_reconnect_cleanup (rpc_clnt_connection_t *conn);
void rpc_clnt_set_connected (rpc_clnt_connection_t *conn);