Refcount grpc_alarm object so that grpc_alarm_destroy can safely be called before the alarm event is dequeued from the completion queue
diff --git a/src/core/lib/surface/alarm.c b/src/core/lib/surface/alarm.c
index ef8405c..343e48c 100644
--- a/src/core/lib/surface/alarm.c
+++ b/src/core/lib/surface/alarm.c
@@ -15,13 +15,19 @@
* limitations under the License.
*
*/
+#include "src/core/lib/surface/alarm_internal.h"
#include <grpc/grpc.h>
#include <grpc/support/alloc.h>
#include "src/core/lib/iomgr/timer.h"
#include "src/core/lib/surface/completion_queue.h"
+#ifndef NDEBUG
+grpc_tracer_flag grpc_trace_alarm_refcount = GRPC_TRACER_INITIALIZER(false);
+#endif
+
struct grpc_alarm {
+ gpr_refcount refs;
grpc_timer alarm;
grpc_closure on_alarm;
grpc_cq_completion completion;
@@ -31,13 +37,58 @@
void *tag;
};
-static void do_nothing_end_completion(grpc_exec_ctx *exec_ctx, void *arg,
- grpc_cq_completion *c) {}
+static void alarm_ref(grpc_alarm *alarm) { gpr_ref(&alarm->refs); }
+
+static void alarm_unref(grpc_alarm *alarm) {
+ if (gpr_unref(&alarm->refs)) {
+ grpc_exec_ctx exec_ctx = GRPC_EXEC_CTX_INIT;
+ GRPC_CQ_INTERNAL_UNREF(&exec_ctx, alarm->cq, "alarm");
+ grpc_exec_ctx_finish(&exec_ctx);
+ gpr_free(alarm);
+ }
+}
+
+#ifndef NDEBUG
+static void alarm_ref_dbg(grpc_alarm *alarm, const char *reason,
+ const char *file, int line) {
+ if (GRPC_TRACER_ON(grpc_trace_alarm_refcount)) {
+ gpr_atm val = gpr_atm_no_barrier_load(&alarm->refs.count);
+ gpr_log(file, line, GPR_LOG_SEVERITY_DEBUG,
+ "Alarm:%p ref %" PRIdPTR " -> %" PRIdPTR " %s", alarm, val,
+ val + 1, reason);
+ }
+
+ alarm_ref(alarm);
+}
+
+static void alarm_unref_dbg(grpc_alarm *alarm, const char *reason,
+ const char *file, int line) {
+ if (GRPC_TRACER_ON(grpc_trace_alarm_refcount)) {
+ gpr_atm val = gpr_atm_no_barrier_load(&alarm->refs.count);
+ gpr_log(file, line, GPR_LOG_SEVERITY_DEBUG,
+ "Alarm:%p Unref %" PRIdPTR " -> %" PRIdPTR " %s", alarm, val,
+ val - 1, reason);
+ }
+
+ alarm_unref(alarm);
+}
+#endif
+
+static void alarm_end_completion(grpc_exec_ctx *exec_ctx, void *arg,
+ grpc_cq_completion *c) {
+ grpc_alarm *alarm = arg;
+ GRPC_ALARM_UNREF(alarm, "dequeue-end-op");
+}
static void alarm_cb(grpc_exec_ctx *exec_ctx, void *arg, grpc_error *error) {
grpc_alarm *alarm = arg;
- grpc_cq_end_op(exec_ctx, alarm->cq, alarm->tag, error,
- do_nothing_end_completion, NULL, &alarm->completion);
+
+ /* We are queuing an op on completion queue. This means, the alarm's structure
+ cannot be destroyed until the op is dequeued. Adding an extra ref
+ here and unref'ing when the op is dequeued will achieve this */
+ GRPC_ALARM_REF(alarm, "queue-end-op");
+ grpc_cq_end_op(exec_ctx, alarm->cq, alarm->tag, error, alarm_end_completion,
+ (void *)alarm, &alarm->completion);
}
grpc_alarm *grpc_alarm_create(grpc_completion_queue *cq, gpr_timespec deadline,
@@ -45,6 +96,14 @@
grpc_alarm *alarm = gpr_malloc(sizeof(grpc_alarm));
grpc_exec_ctx exec_ctx = GRPC_EXEC_CTX_INIT;
+ gpr_ref_init(&alarm->refs, 1);
+
+#ifndef NDEBUG
+ if (GRPC_TRACER_ON(grpc_trace_alarm_refcount)) {
+ gpr_log(GPR_DEBUG, "Alarm:%p created (ref: 1)", alarm);
+ }
+#endif
+
GRPC_CQ_INTERNAL_REF(cq, "alarm");
alarm->cq = cq;
alarm->tag = tag;
@@ -66,9 +125,6 @@
}
void grpc_alarm_destroy(grpc_alarm *alarm) {
- grpc_exec_ctx exec_ctx = GRPC_EXEC_CTX_INIT;
grpc_alarm_cancel(alarm);
- GRPC_CQ_INTERNAL_UNREF(&exec_ctx, alarm->cq, "alarm");
- gpr_free(alarm);
- grpc_exec_ctx_finish(&exec_ctx);
+ GRPC_ALARM_UNREF(alarm, "alarm_destroy");
}
diff --git a/src/core/lib/surface/alarm_internal.h b/src/core/lib/surface/alarm_internal.h
new file mode 100644
index 0000000..a9b0968
--- /dev/null
+++ b/src/core/lib/surface/alarm_internal.h
@@ -0,0 +1,39 @@
+/*
+ *
+ * Copyright 2015-2017 gRPC authors.
+ *
+ * Licensed under the Apache License, Version 2.0 (the "License");
+ * you may not use this file except in compliance with the License.
+ * You may obtain a copy of the License at
+ *
+ * http://www.apache.org/licenses/LICENSE-2.0
+ *
+ * Unless required by applicable law or agreed to in writing, software
+ * distributed under the License is distributed on an "AS IS" BASIS,
+ * WITHOUT WARRANTIES OR CONDITIONS OF ANY KIND, either express or implied.
+ * See the License for the specific language governing permissions and
+ * limitations under the License.
+ *
+ */
+
+#ifndef GRPC_CORE_LIB_SURFACE_ALARM_INTERNAL_H
+#define GRPC_CORE_LIB_SURFACE_ALARM_INTERNAL_H
+
+#include <grpc/support/log.h>
+#include "src/core/lib/debug/trace.h"
+
+#ifndef NDEBUG
+
+extern grpc_tracer_flag grpc_trace_alarm_refcount;
+#define GRPC_ALARM_REF(a, reason) alarm_ref_dbg(a, reason, __FILE__, __LINE__)
+#define GRPC_ALARM_UNREF(a, reason) \
+ alarm_unref_dbg(a, reason, __FILE__, __LINE__)
+
+#else /* !defined(NDEBUG) */
+
+#define GRPC_ALARM_REF(a, reason) alarm_ref(a)
+#define GRPC_ALARM_UNREF(a, reason) alarm_unref(a)
+
+#endif /* defined(NDEBUG) */
+
+#endif // GRPC_CORE_LIB_SURFACE_ALARM_INTERNAL_H
diff --git a/src/core/lib/surface/init.c b/src/core/lib/surface/init.c
index 14a86bf..7a5f398 100644
--- a/src/core/lib/surface/init.c
+++ b/src/core/lib/surface/init.c
@@ -36,6 +36,7 @@
#include "src/core/lib/iomgr/resource_quota.h"
#include "src/core/lib/profiling/timers.h"
#include "src/core/lib/slice/slice_internal.h"
+#include "src/core/lib/surface/alarm_internal.h"
#include "src/core/lib/surface/api_trace.h"
#include "src/core/lib/surface/call.h"
#include "src/core/lib/surface/channel_init.h"
@@ -137,6 +138,7 @@
grpc_register_tracer("call_error", &grpc_call_error_trace);
#ifndef NDEBUG
grpc_register_tracer("pending_tags", &grpc_trace_pending_tags);
+ grpc_register_tracer("alarm_refcount", &grpc_trace_alarm_refcount);
grpc_register_tracer("queue_refcount", &grpc_trace_cq_refcount);
grpc_register_tracer("closure", &grpc_trace_closure);
grpc_register_tracer("error_refcount", &grpc_trace_error_refcount);