Address lock order inversions.

    WARNING: ThreadSanitizer: lock-order-inversion (potential deadlock)
    Cycle in lock order graph: M1 (0x000000000000) => M2 (0x000000000000) => M1

    Mutex M2 acquired here while holding mutex M1 in thread T1:
    #0 pthread_mutex_lock <null>
    #1 dns_view_findzonecut lib/dns/view.c:1310:2
    #2 fctx_create lib/dns/resolver.c:5070:13
    #3 dns_resolver_createfetch lib/dns/resolver.c:10813:12
    #4 dns_resolver_prime lib/dns/resolver.c:10442:12
    #5 dns_view_find lib/dns/view.c:1176:4
    #6 dbfind_name lib/dns/adb.c:3833:11
    #7 dns_adb_createfind lib/dns/adb.c:3155:12
    #8 findname lib/dns/resolver.c:3497:11
    #9 fctx_getaddresses lib/dns/resolver.c:3808:3
    #10 fctx_try lib/dns/resolver.c:4197:12
    #11 fctx_start lib/dns/resolver.c:4824:4
    #12 dispatch lib/isc/task.c:1152:7
    #13 run lib/isc/task.c:1344:2

    Mutex M1 previously acquired by the same thread here:
    #0 pthread_mutex_lock <null>
    #1 dns_resolver_createfetch lib/dns/resolver.c:10767:2
    #2 dns_resolver_prime lib/dns/resolver.c:10442:12
    #3 dns_view_find lib/dns/view.c:1176:4
    #4 dbfind_name lib/dns/adb.c:3833:11
    #5 dns_adb_createfind lib/dns/adb.c:3155:12
    #6 findname lib/dns/resolver.c:3497:11
    #7 fctx_getaddresses lib/dns/resolver.c:3808:3
    #8 fctx_try lib/dns/resolver.c:4197:12
    #9 fctx_start lib/dns/resolver.c:4824:4
    #10 dispatch lib/isc/task.c:1152:7
    #11 run lib/isc/task.c:1344:2

    Mutex M1 acquired here while holding mutex M2 in thread T1:
    #0 pthread_mutex_lock <null>
    #1 dns_resolver_shutdown lib/dns/resolver.c:10530:4
    #2 view_flushanddetach lib/dns/view.c:632:4
    #3 dns_view_detach lib/dns/view.c:689:2
    #4 qctx_destroy lib/ns/query.c:5152:2
    #5 fetch_callback lib/ns/query.c:5749:3
    #6 dispatch lib/isc/task.c:1152:7
    #7 run lib/isc/task.c:1344:2

    Mutex M2 previously acquired by the same thread here:
    #0 pthread_mutex_lock <null>
    #1 view_flushanddetach lib/dns/view.c:630:3
    #2 dns_view_detach lib/dns/view.c:689:2
    #3 qctx_destroy lib/ns/query.c:5152:2
    #4 fetch_callback lib/ns/query.c:5749:3
    #5 dispatch lib/isc/task.c:1152:7
    #6 run lib/isc/task.c:1344:2

    Thread T1 (running) created by main thread at:
    #0 pthread_create <null>
    #1 isc_thread_create lib/isc/pthreads/thread.c:73:8
    #2 isc_taskmgr_create lib/isc/task.c:1434:3
    #3 create_managers bin/named/main.c:915:11
    #4 setup bin/named/main.c:1223:11
    #5 main bin/named/main.c:1523:2

    SUMMARY: ThreadSanitizer: lock-order-inversion (potential deadlock) in pthread_mutex_lock

diff --git a/lib/dns/view.c b/lib/dns/view.c
index 70111e20345d513aa4771a8d743fe902d39bc956..42c17dc6dae92e1c267364d52cfdff5b205a8f4c 100644 (file)
--- a/lib/dns/view.c
+++ b/lib/dns/view.c
@@ -627,7 +627,6 @@ view_flushanddetach(dns_view_t **viewp, bool flush) {
                dns_zone_t *mkzone = NULL, *rdzone = NULL;
 
                isc_refcount_destroy(&view->references);
-               LOCK(&view->lock);
                if (!RESSHUTDOWN(view)) {
                        dns_resolver_shutdown(view->resolver);
                }
@@ -637,6 +636,7 @@ view_flushanddetach(dns_view_t **viewp, bool flush) {
                if (!REQSHUTDOWN(view)) {
                        dns_requestmgr_shutdown(view->requestmgr);
                }
+               LOCK(&view->lock);
                if (view->zonetable != NULL) {
                        if (view->flush) {
                                dns_zt_flushanddetach(&view->zonetable);