From 29dcdeba1b99236253298808fa513f114b8162bc Mon Sep 17 00:00:00 2001 From: Evan Hunt Date: Fri, 3 Jul 2020 15:34:51 -0700 Subject: [PATCH] purge pending command events when shutting down When we're shutting the system down via "rndc stop" or "rndc halt", or reconfiguring the control channel, there are potential shutdown races between the server task and network manager. These are adressed by: - purging any pending command tasks when shutting down the control channel - adding an extra handle reference before the command handler to ensure the handle can't be deleted out from under us before calling command_respond() --- bin/named/controlconf.c | 17 +++++++++++++++-- 1 file changed, 15 insertions(+), 2 deletions(-) diff --git a/bin/named/controlconf.c b/bin/named/controlconf.c index 924b8a74f6..c69650ace5 100644 --- a/bin/named/controlconf.c +++ b/bin/named/controlconf.c @@ -330,7 +330,6 @@ control_respond(isc_nmhandle_t *handle, isc_result_t result, void *arg) { if (result != ISC_R_SUCCESS) { isc_nmhandle_unref(handle); conn->sending = false; - goto cleanup; } cleanup: @@ -357,10 +356,17 @@ control_command(isc_task_t *task, isc_event_t *event) { UNUSED(task); + /* + * An extra ref and two unrefs are needed here to + * ensure the handle isn't cleaned up if we're running + * an "rndc stop" command. + */ + isc_nmhandle_ref(conn->handle); conn->result = named_control_docommand(conn->request, listener->readonly, &conn->text); control_respond(conn->handle, conn->result, conn); isc_nmhandle_unref(conn->handle); + isc_nmhandle_unref(conn->handle); isc_event_free(&event); } @@ -382,7 +388,14 @@ control_recvmessage(isc_nmhandle_t *handle, isc_result_t result, void *arg) { } if (result != ISC_R_SUCCESS) { - if (result != ISC_R_CANCELED && result != ISC_R_EOF) { + if (result == ISC_R_CANCELED) { + /* + * Don't bother with any more scheduled command events. + */ + listener->controls->shuttingdown = true; + isc_task_purge(named_g_server->task, NULL, + NAMED_EVENT_COMMAND, NULL); + } else if (result != ISC_R_EOF) { log_invalid(&conn->ccmsg, result); }