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authorPeter Maydell <peter.maydell@linaro.org>2018-07-31 18:02:11 +0100
committerPeter Maydell <peter.maydell@linaro.org>2018-07-31 18:02:11 +0100
commitb89041647422e2a8989ab1d521dd11f3e1eb5d20 (patch)
tree2b2bedd333fcbf1083f85718acb97dab1b9e56b6
parent42e76456cf68dc828b8dbd3c7e255197e9b5e57d (diff)
parent9a1054061c62311f6efcd88e4df0aa5203c7b39a (diff)
downloadqemu-arm-b89041647422e2a8989ab1d521dd11f3e1eb5d20.tar.gz
Merge remote-tracking branch 'remotes/armbru/tags/pull-monitor-2018-07-31' into staging
Monitor patches for 2018-07-31 (3.0.0-rc3) # gpg: Signature made Tue 31 Jul 2018 16:46:16 BST # gpg: using RSA key 3870B400EB918653 # gpg: Good signature from "Markus Armbruster <armbru@redhat.com>" # gpg: aka "Markus Armbruster <armbru@pond.sub.org>" # Primary key fingerprint: 354B C8B3 D7EB 2A6B 6867 4E5F 3870 B400 EB91 8653 * remotes/armbru/tags/pull-monitor-2018-07-31: monitor: temporary fix for dead-lock on event recursion Signed-off-by: Peter Maydell <peter.maydell@linaro.org>
-rw-r--r--monitor.c44
1 files changed, 43 insertions, 1 deletions
diff --git a/monitor.c b/monitor.c
index f75027b09e..77861e96af 100644
--- a/monitor.c
+++ b/monitor.c
@@ -633,7 +633,7 @@ static void monitor_qapi_event_handler(void *opaque);
* applying any rate limiting if required.
*/
static void
-monitor_qapi_event_queue(QAPIEvent event, QDict *qdict, Error **errp)
+monitor_qapi_event_queue_no_reenter(QAPIEvent event, QDict *qdict)
{
MonitorQAPIEventConf *evconf;
MonitorQAPIEventState *evstate;
@@ -688,6 +688,48 @@ monitor_qapi_event_queue(QAPIEvent event, QDict *qdict, Error **errp)
qemu_mutex_unlock(&monitor_lock);
}
+static void
+monitor_qapi_event_queue(QAPIEvent event, QDict *qdict, Error **errp)
+{
+ /*
+ * monitor_qapi_event_queue_no_reenter() is not reentrant: it
+ * would deadlock on monitor_lock. Work around by queueing
+ * events in thread-local storage.
+ * TODO: remove this, make it re-enter safe.
+ */
+ typedef struct MonitorQapiEvent {
+ QAPIEvent event;
+ QDict *qdict;
+ QSIMPLEQ_ENTRY(MonitorQapiEvent) entry;
+ } MonitorQapiEvent;
+ static __thread QSIMPLEQ_HEAD(, MonitorQapiEvent) event_queue;
+ static __thread bool reentered;
+ MonitorQapiEvent *ev;
+
+ if (!reentered) {
+ QSIMPLEQ_INIT(&event_queue);
+ }
+
+ ev = g_new(MonitorQapiEvent, 1);
+ ev->qdict = qobject_ref(qdict);
+ ev->event = event;
+ QSIMPLEQ_INSERT_TAIL(&event_queue, ev, entry);
+ if (reentered) {
+ return;
+ }
+
+ reentered = true;
+
+ while ((ev = QSIMPLEQ_FIRST(&event_queue)) != NULL) {
+ QSIMPLEQ_REMOVE_HEAD(&event_queue, entry);
+ monitor_qapi_event_queue_no_reenter(ev->event, ev->qdict);
+ qobject_unref(ev->qdict);
+ g_free(ev);
+ }
+
+ reentered = false;
+}
+
/*
* This function runs evconf->rate ns after sending a throttled
* event.