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authorWolfgang Bumiller <w.bumiller@proxmox.com>2018-09-25 10:15:07 +0200
committerMarkus Armbruster <armbru@redhat.com>2018-11-06 17:02:49 +0100
commit8511770185f5769d06e7c3e37b2fd79f268cf84c (patch)
tree685b15e70b8d986110cae990c81ec688e83f4013
parent9a3e52e3465f85d203d0fd2910ca3625b3c45420 (diff)
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monitor: delay monitor iothread creation
Commit d32749deb615 moved the call to monitor_init_globals() to before os_daemonize(), making it an unsuitable place to spawn the monitor iothread as it won't be inherited over the fork() in os_daemonize(). We now spawn the thread the first time we instantiate a monitor which actually has use_io_thread == true. Instantiation of monitors happens only after os_daemonize(). We still need to create the qmp_dispatcher_bh when not using iothreads, so this now still happens in monitor_init_globals(). Signed-off-by: Wolfgang Bumiller <w.bumiller@proxmox.com> Fixes: d32749deb615 ("monitor: move init global earlier") Message-Id: <20180925081507.11873-3-w.bumiller@proxmox.com> Reviewed-by: Eric Blake <eblake@redhat.com> Reviewed-by: Peter Xu <peterx@redhat.com> Tested-by: Peter Xu <peterx@redhat.com> [This fixes a crash on shutdown with --daemonize] Signed-off-by: Markus Armbruster <armbru@redhat.com>
-rw-r--r--monitor.c35
1 files changed, 21 insertions, 14 deletions
diff --git a/monitor.c b/monitor.c
index 66f149c..d39390c 100644
--- a/monitor.c
+++ b/monitor.c
@@ -708,9 +708,14 @@ static void monitor_qapi_event_init(void)
static void handle_hmp_command(Monitor *mon, const char *cmdline);
+static void monitor_iothread_init(void);
+
static void monitor_data_init(Monitor *mon, bool skip_flush,
bool use_io_thread)
{
+ if (use_io_thread && !mon_iothread) {
+ monitor_iothread_init();
+ }
memset(mon, 0, sizeof(Monitor));
qemu_mutex_init(&mon->mon_lock);
qemu_mutex_init(&mon->qmp.qmp_queue_lock);
@@ -4461,15 +4466,6 @@ static AioContext *monitor_get_aio_context(void)
static void monitor_iothread_init(void)
{
mon_iothread = iothread_create("mon_iothread", &error_abort);
-
- /*
- * The dispatcher BH must run in the main loop thread, since we
- * have commands assuming that context. It would be nice to get
- * rid of those assumptions.
- */
- qmp_dispatcher_bh = aio_bh_new(iohandler_get_aio_context(),
- monitor_qmp_bh_dispatcher,
- NULL);
}
void monitor_init_globals(void)
@@ -4479,7 +4475,15 @@ void monitor_init_globals(void)
sortcmdlist();
qemu_mutex_init(&monitor_lock);
qemu_mutex_init(&mon_fdsets_lock);
- monitor_iothread_init();
+
+ /*
+ * The dispatcher BH must run in the main loop thread, since we
+ * have commands assuming that context. It would be nice to get
+ * rid of those assumptions.
+ */
+ qmp_dispatcher_bh = aio_bh_new(iohandler_get_aio_context(),
+ monitor_qmp_bh_dispatcher,
+ NULL);
}
/* These functions just adapt the readline interface in a typesafe way. We
@@ -4624,7 +4628,9 @@ void monitor_cleanup(void)
* we need to unregister from chardev below in
* monitor_data_destroy(), and chardev is not thread-safe yet
*/
- iothread_stop(mon_iothread);
+ if (mon_iothread) {
+ iothread_stop(mon_iothread);
+ }
/* Flush output buffers and destroy monitors */
qemu_mutex_lock(&monitor_lock);
@@ -4639,9 +4645,10 @@ void monitor_cleanup(void)
/* QEMUBHs needs to be deleted before destroying the I/O thread */
qemu_bh_delete(qmp_dispatcher_bh);
qmp_dispatcher_bh = NULL;
-
- iothread_destroy(mon_iothread);
- mon_iothread = NULL;
+ if (mon_iothread) {
+ iothread_destroy(mon_iothread);
+ mon_iothread = NULL;
+ }
}
QemuOptsList qemu_mon_opts = {