From 3ed7746ec92e69a9c37b4b34c6f0fce06b7ba592 Mon Sep 17 00:00:00 2001 From: Mark Andrews Date: Mon, 24 Aug 2020 11:44:09 +1000 Subject: [PATCH] Address lock-order-inversion Obtain references to view->redirect and view->managed_keys then release view->lock so dns_zone_setviewcommit and dns_zone_setviewrevert can obtain the view->lock while holding zone->lock. WARNING: ThreadSanitizer: lock-order-inversion (potential deadlock) (pid=9132) Cycle in lock order graph: M987831431424375936 (0x000000000000) => M1012319771577875480 (0x000000000000) => M987831431424375936 Mutex M1012319771577875480 acquired here while holding mutex M987831431424375936 in thread T2: #0 pthread_mutex_lock (named+0x4642a6) #1 dns_zone_setviewcommit /builds/isc-projects/bind9/lib/dns/zone.c:1571:2 (libdns.so.1110+0x1d74eb) #2 dns_view_setviewcommit /builds/isc-projects/bind9/lib/dns/view.c:2388:3 (libdns.so.1110+0x1cfe29) #3 load_configuration /builds/isc-projects/bind9/bin/named/./server.c:8188:3 (named+0x51eadd) #4 loadconfig /builds/isc-projects/bind9/bin/named/./server.c:9438:11 (named+0x510c66) #5 ns_server_reconfigcommand /builds/isc-projects/bind9/bin/named/./server.c:9773:2 (named+0x510b41) #6 ns_control_docommand /builds/isc-projects/bind9/bin/named/control.c:243:12 (named+0x4e451a) #7 control_recvmessage /builds/isc-projects/bind9/bin/named/controlconf.c:465:13 (named+0x4e9056) #8 dispatch /builds/isc-projects/bind9/lib/isc/task.c:1157:7 (libisc.so.1107+0x507d5) #9 run /builds/isc-projects/bind9/lib/isc/task.c:1331:2 (libisc.so.1107+0x4d729) Mutex M987831431424375936 previously acquired by the same thread here: #0 pthread_mutex_lock (named+0x4642a6) #1 dns_view_setviewcommit /builds/isc-projects/bind9/lib/dns/view.c:2382:2 (libdns.so.1110+0x1cfde7) #2 load_configuration /builds/isc-projects/bind9/bin/named/./server.c:8188:3 (named+0x51eadd) #3 loadconfig /builds/isc-projects/bind9/bin/named/./server.c:9438:11 (named+0x510c66) #4 ns_server_reconfigcommand /builds/isc-projects/bind9/bin/named/./server.c:9773:2 (named+0x510b41) #5 ns_control_docommand /builds/isc-projects/bind9/bin/named/control.c:243:12 (named+0x4e451a) #6 control_recvmessage /builds/isc-projects/bind9/bin/named/controlconf.c:465:13 (named+0x4e9056) #7 dispatch /builds/isc-projects/bind9/lib/isc/task.c:1157:7 (libisc.so.1107+0x507d5) #8 run /builds/isc-projects/bind9/lib/isc/task.c:1331:2 (libisc.so.1107+0x4d729) Mutex M987831431424375936 acquired here while holding mutex M1012319771577875480 in thread T7: #0 pthread_mutex_lock (named+0x4642a6) #1 dns_view_findzonecut2 /builds/isc-projects/bind9/lib/dns/view.c:1300:2 (libdns.so.1110+0x1cc93a) #2 dns_view_findzonecut /builds/isc-projects/bind9/lib/dns/view.c:1261:9 (libdns.so.1110+0x1cc864) #3 fctx_create /builds/isc-projects/bind9/lib/dns/resolver.c:4459:13 (libdns.so.1110+0x1779d3) #4 dns_resolver_createfetch3 /builds/isc-projects/bind9/lib/dns/resolver.c:9628:12 (libdns.so.1110+0x176cb6) #5 dns_resolver_createfetch /builds/isc-projects/bind9/lib/dns/resolver.c:9504:10 (libdns.so.1110+0x174e17) #6 zone_refreshkeys /builds/isc-projects/bind9/lib/dns/zone.c:10061:12 (libdns.so.1110+0x2055a5) #7 zone_maintenance /builds/isc-projects/bind9/lib/dns/zone.c:10274:5 (libdns.so.1110+0x203a78) #8 zone_timer /builds/isc-projects/bind9/lib/dns/zone.c:13106:2 (libdns.so.1110+0x1e815a) #9 dispatch /builds/isc-projects/bind9/lib/isc/task.c:1157:7 (libisc.so.1107+0x507d5) #10 run /builds/isc-projects/bind9/lib/isc/task.c:1331:2 (libisc.so.1107+0x4d729) Mutex M1012319771577875480 previously acquired by the same thread here: #0 pthread_mutex_lock (named+0x4642a6) #1 zone_refreshkeys /builds/isc-projects/bind9/lib/dns/zone.c:9951:2 (libdns.so.1110+0x204dc3) #2 zone_maintenance /builds/isc-projects/bind9/lib/dns/zone.c:10274:5 (libdns.so.1110+0x203a78) #3 zone_timer /builds/isc-projects/bind9/lib/dns/zone.c:13106:2 (libdns.so.1110+0x1e815a) #4 dispatch /builds/isc-projects/bind9/lib/isc/task.c:1157:7 (libisc.so.1107+0x507d5) #5 run /builds/isc-projects/bind9/lib/isc/task.c:1331:2 (libisc.so.1107+0x4d729) Thread T2 'isc-worker0001' (tid=9163, running) created by main thread at: #0 pthread_create (named+0x446edb) #1 isc_thread_create /builds/isc-projects/bind9/lib/isc/pthreads/thread.c:60:8 (libisc.so.1107+0x726d8) #2 isc__taskmgr_create /builds/isc-projects/bind9/lib/isc/task.c:1468:7 (libisc.so.1107+0x4d635) #3 isc_taskmgr_create /builds/isc-projects/bind9/lib/isc/task.c:2109:11 (libisc.so.1107+0x4f587) #4 create_managers /builds/isc-projects/bind9/bin/named/./main.c:886:11 (named+0x4f1a97) #5 setup /builds/isc-projects/bind9/bin/named/./main.c:1305:11 (named+0x4f05ee) #6 main /builds/isc-projects/bind9/bin/named/./main.c:1556:2 (named+0x4ef12d) Thread T7 'isc-worker0006' (tid=9168, running) created by main thread at: #0 pthread_create (named+0x446edb) #1 isc_thread_create /builds/isc-projects/bind9/lib/isc/pthreads/thread.c:60:8 (libisc.so.1107+0x726d8) #2 isc__taskmgr_create /builds/isc-projects/bind9/lib/isc/task.c:1468:7 (libisc.so.1107+0x4d635) #3 isc_taskmgr_create /builds/isc-projects/bind9/lib/isc/task.c:2109:11 (libisc.so.1107+0x4f587) #4 create_managers /builds/isc-projects/bind9/bin/named/./main.c:886:11 (named+0x4f1a97) #5 setup /builds/isc-projects/bind9/bin/named/./main.c:1305:11 (named+0x4f05ee) #6 main /builds/isc-projects/bind9/bin/named/./main.c:1556:2 (named+0x4ef12d) SUMMARY: ThreadSanitizer: lock-order-inversion (potential deadlock) (/builds/isc-projects/bind9/bin/named/.libs/named+0x4642a6) in pthread_mutex_lock Conflict: NA Reference: https://gitlab.isc.org/isc-projects/bind9/-/commit/3ed7746ec92e69a9c37b4b34c6f0fce06b7ba592 --- lib/dns/view.c | 28 ++++++++++++++++++++++++---- 1 file changed, 24 insertions(+), 4 deletions(-) diff --git a/lib/dns/view.c b/lib/dns/view.c index 006f99794d..0a5559ac9d 100644 --- a/lib/dns/view.c +++ b/lib/dns/view.c @@ -2377,25 +2377,37 @@ dns_view_loadnta(dns_view_t *view) { void dns_view_setviewcommit(dns_view_t *view) { + dns_zone_t *redirect = NULL, *managed_keys = NULL; + REQUIRE(DNS_VIEW_VALID(view)); LOCK(&view->lock); if (view->redirect != NULL) { - dns_zone_setviewcommit(view->redirect); + dns_zone_attach(view->redirect, &redirect); } if (view->managed_keys != NULL) { - dns_zone_setviewcommit(view->managed_keys); + dns_zone_attach(view->managed_keys, &managed_keys); } if (view->zonetable != NULL) { dns_zt_setviewcommit(view->zonetable); } UNLOCK(&view->lock); + + if (redirect != NULL) { + dns_zone_setviewcommit(redirect); + dns_zone_detach(&redirect); + } + if (managed_keys != NULL) { + dns_zone_setviewcommit(managed_keys); + dns_zone_detach(&managed_keys); + } } void dns_view_setviewrevert(dns_view_t *view) { + dns_zone_t *redirect = NULL, *managed_keys = NULL; dns_zt_t *zonetable; REQUIRE(DNS_VIEW_VALID(view)); @@ -2406,14 +2418,22 @@ dns_view_setviewrevert(dns_view_t *view) { */ LOCK(&view->lock); if (view->redirect != NULL) { - dns_zone_setviewrevert(view->redirect); + dns_zone_attach(view->redirect, &redirect); } if (view->managed_keys != NULL) { - dns_zone_setviewrevert(view->managed_keys); + dns_zone_attach(view->managed_keys, &managed_keys); } zonetable = view->zonetable; UNLOCK(&view->lock); + if (redirect != NULL) { + dns_zone_setviewrevert(redirect); + dns_zone_detach(&redirect); + } + if (managed_keys != NULL) { + dns_zone_setviewrevert(managed_keys); + dns_zone_detach(&managed_keys); + } if (zonetable != NULL) { dns_zt_setviewrevert(zonetable); } -- 2.23.0