From ac942f430f5219633111774d95b1d7a68aaf0dee Mon Sep 17 00:00:00 2001
From: Craig Tiller <ctiller@google.com>
Date: Wed, 22 Feb 2017 09:13:14 -0800
Subject: [PATCH] Fix refcounting bug
---
src/core/lib/channel/deadline_filter.c | 15 ++++++++++-----
1 file changed, 10 insertions(+), 5 deletions(-)
diff --git a/src/core/lib/channel/deadline_filter.c b/src/core/lib/channel/deadline_filter.c
index 8a8c3cb830..f9668be0fa 100644
--- a/src/core/lib/channel/deadline_filter.c
+++ b/src/core/lib/channel/deadline_filter.c
@@ -43,8 +43,6 @@
#include "src/core/lib/iomgr/timer.h"
#include "src/core/lib/slice/slice_internal.h"
-#define TOMBSTONE_TIMER 1
-
//
// grpc_deadline_state
//
@@ -80,11 +78,15 @@ retry:
(grpc_deadline_timer_state)gpr_atm_acq_load(&deadline_state->timer_state);
switch (cur_state) {
case GRPC_DEADLINE_STATE_PENDING:
+ // Note: We do not start the timer if there is already a timer
return;
case GRPC_DEADLINE_STATE_FINISHED:
if (gpr_atm_rel_cas(&deadline_state->timer_state,
GRPC_DEADLINE_STATE_FINISHED,
GRPC_DEADLINE_STATE_PENDING)) {
+ // If we've already created and destroyed a timer, we always create a
+ // new closure: we have no other guarantee that the inlined closure is
+ // not in use (it may hold a pending call to timer_callback)
closure = grpc_closure_create(timer_callback, elem,
grpc_schedule_on_exec_ctx);
} else {
@@ -104,17 +106,20 @@ retry:
break;
}
GPR_ASSERT(closure);
+ GRPC_CALL_STACK_REF(deadline_state->call_stack, "deadline_timer");
grpc_timer_init(exec_ctx, &deadline_state->timer, deadline, closure,
gpr_now(GPR_CLOCK_MONOTONIC));
- GPR_UNREACHABLE_CODE(return;);
}
// Cancels the deadline timer.
static void cancel_timer_if_needed(grpc_exec_ctx* exec_ctx,
grpc_deadline_state* deadline_state) {
- if (gpr_atm_acq_load(&deadline_state->timer_state) !=
- GRPC_DEADLINE_STATE_INITIAL) {
+ if (gpr_atm_rel_cas(&deadline_state->timer_state, GRPC_DEADLINE_STATE_PENDING,
+ GRPC_DEADLINE_STATE_FINISHED)) {
grpc_timer_cancel(exec_ctx, &deadline_state->timer);
+ } else {
+ // timer was either in STATE_INITAL (nothing to cancel)
+ // OR in STATE_FINISHED (again nothing to cancel)
}
}
--
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