From 9b663419711ee2beb92c1c34a79669b251e7562d Mon Sep 17 00:00:00 2001 From: Mark Andrews Date: Thu, 20 Aug 2020 12:46:24 +1000 Subject: [PATCH] Lock access when updating/reading manager->epoll_events[fd] WARNING: ThreadSanitizer: data race (pid=110) Write of size 4 at 0x7ba400014050 by main thread (mutexes: write M1100, write M75): #0 socket_create /builds/isc-projects/bind9/lib/isc/unix/socket.c:3012:34 (libisc.so.1105+0x6085c) #1 isc__socket_create /builds/isc-projects/bind9/lib/isc/unix/socket.c:3044:10 (libisc.so.1105+0x60583) #2 isc_socket_create /builds/isc-projects/bind9/lib/isc/unix/./../socket_api.c:105:11 (libisc.so.1105+0x6a4a0) #3 open_socket /builds/isc-projects/bind9/lib/dns/dispatch.c:1708:12 (libdns.so.1110+0x7491c) #4 get_udpsocket /builds/isc-projects/bind9/lib/dns/dispatch.c:2904:13 (libdns.so.1110+0x745ec) #5 dispatch_createudp /builds/isc-projects/bind9/lib/dns/dispatch.c:2994:12 (libdns.so.1110+0x6e159) #6 dns_dispatch_getudp_dup /builds/isc-projects/bind9/lib/dns/dispatch.c:2823:11 (libdns.so.1110+0x6d8f2) #7 dns_dispatch_getudp /builds/isc-projects/bind9/lib/dns/dispatch.c:2849:10 (libdns.so.1110+0x6e99e) #8 make_dispatchset /builds/isc-projects/bind9/lib/dns/tests/dispatch_test.c:81:11 (dispatch_test+0x4ba8fc) #9 dispatchset_create /builds/isc-projects/bind9/lib/dns/tests/dispatch_test.c:115:11 (dispatch_test+0x4b9f99) #10 (libcmocka.so.0+0x50d8) #11 __libc_start_main /build/glibc-vjB4T1/glibc-2.28/csu/../csu/libc-start.c:308:16 (libc.so.6+0x2409a) Previous write of size 4 at 0x7ba400014050 by thread T14: #0 unwatch_fd /builds/isc-projects/bind9/lib/isc/unix/socket.c (libisc.so.1105+0x6b913) #1 wakeup_socket /builds/isc-projects/bind9/lib/isc/unix/socket.c:1128:9 (libisc.so.1105+0x701fc) #2 process_ctlfd /builds/isc-projects/bind9/lib/isc/unix/socket.c:4253:3 (libisc.so.1105+0x6c048) #3 process_fds /builds/isc-projects/bind9/lib/isc/unix/socket.c:4157:10 (libisc.so.1105+0x6bcb4) #4 watcher /builds/isc-projects/bind9/lib/isc/unix/socket.c:4396:10 (libisc.so.1105+0x64188) Location is heap block of size 16385 at 0x7ba400014000 allocated by main thread: #0 malloc (dispatch_test+0x42b7c4) #1 internal_memalloc /builds/isc-projects/bind9/lib/isc/mem.c:887:8 (libisc.so.1105+0x37e38) #2 mem_get /builds/isc-projects/bind9/lib/isc/mem.c:792:8 (libisc.so.1105+0x32c2c) #3 isc___mem_get /builds/isc-projects/bind9/lib/isc/mem.c:1310:9 (libisc.so.1105+0x325d7) #4 isc__mem_get /builds/isc-projects/bind9/lib/isc/mem.c:3012:11 (libisc.so.1105+0x34f80) #5 isc__socketmgr_create2 /builds/isc-projects/bind9/lib/isc/unix/socket.c:4704:26 (libisc.so.1105+0x6379a) #6 isc__socketmgr_create /builds/isc-projects/bind9/lib/isc/unix/socket.c:4652:10 (libisc.so.1105+0x635f2) #7 isc_socketmgr_create /builds/isc-projects/bind9/lib/isc/unix/./../socket_api.c:74:11 (libisc.so.1105+0x6a2c7) #8 create_managers /builds/isc-projects/bind9/lib/dns/tests/dnstest.c:120:2 (dispatch_test+0x4bb28a) #9 dns_test_begin /builds/isc-projects/bind9/lib/dns/tests/dnstest.c:192:3 (dispatch_test+0x4bb182) #10 _setup /builds/isc-projects/bind9/lib/dns/tests/dispatch_test.c:53:11 (dispatch_test+0x4b9ff8) #11 (libcmocka.so.0+0x51e2) #12 __libc_start_main /build/glibc-vjB4T1/glibc-2.28/csu/../csu/libc-start.c:308:16 (libc.so.6+0x2409a) Mutex M1100 (0x7b5000000230) created at: #0 pthread_mutex_init (dispatch_test+0x42e60d) #1 isc__mutex_init /builds/isc-projects/bind9/lib/isc/pthreads/mutex.c:287:8 (libisc.so.1105+0x72377) #2 dns_dispatchmgr_create /builds/isc-projects/bind9/lib/dns/dispatch.c:1778:11 (libdns.so.1110+0x6a055) #3 make_dispatchset /builds/isc-projects/bind9/lib/dns/tests/dispatch_test.c:75:11 (dispatch_test+0x4ba883) #4 dispatchset_create /builds/isc-projects/bind9/lib/dns/tests/dispatch_test.c:115:11 (dispatch_test+0x4b9f99) #5 (libcmocka.so.0+0x50d8) #6 __libc_start_main /build/glibc-vjB4T1/glibc-2.28/csu/../csu/libc-start.c:308:16 (libc.so.6+0x2409a) Mutex M75 (0x7bb800000320) created at: #0 pthread_mutex_init (dispatch_test+0x42e60d) #1 isc__mutex_init /builds/isc-projects/bind9/lib/isc/pthreads/mutex.c:287:8 (libisc.so.1105+0x72377) #2 isc__socketmgr_create2 /builds/isc-projects/bind9/lib/isc/unix/socket.c:4729:12 (libisc.so.1105+0x63914) #3 isc__socketmgr_create /builds/isc-projects/bind9/lib/isc/unix/socket.c:4652:10 (libisc.so.1105+0x635f2) #4 isc_socketmgr_create /builds/isc-projects/bind9/lib/isc/unix/./../socket_api.c:74:11 (libisc.so.1105+0x6a2c7) #5 create_managers /builds/isc-projects/bind9/lib/dns/tests/dnstest.c:120:2 (dispatch_test+0x4bb28a) #6 dns_test_begin /builds/isc-projects/bind9/lib/dns/tests/dnstest.c:192:3 (dispatch_test+0x4bb182) #7 _setup /builds/isc-projects/bind9/lib/dns/tests/dispatch_test.c:53:11 (dispatch_test+0x4b9ff8) #8 (libcmocka.so.0+0x51e2) #9 __libc_start_main /build/glibc-vjB4T1/glibc-2.28/csu/../csu/libc-start.c:308:16 (libc.so.6+0x2409a) Thread T14 'isc-socket' (tid=150, running) created by main thread at: #0 pthread_create (dispatch_test+0x42d08b) #1 isc_thread_create /builds/isc-projects/bind9/lib/isc/pthreads/thread.c:60:8 (libisc.so.1105+0x724e8) #2 isc__socketmgr_create2 /builds/isc-projects/bind9/lib/isc/unix/socket.c:4788:6 (libisc.so.1105+0x63cc6) #3 isc__socketmgr_create /builds/isc-projects/bind9/lib/isc/unix/socket.c:4652:10 (libisc.so.1105+0x635f2) #4 isc_socketmgr_create /builds/isc-projects/bind9/lib/isc/unix/./../socket_api.c:74:11 (libisc.so.1105+0x6a2c7) #5 create_managers /builds/isc-projects/bind9/lib/dns/tests/dnstest.c:120:2 (dispatch_test+0x4bb28a) #6 dns_test_begin /builds/isc-projects/bind9/lib/dns/tests/dnstest.c:192:3 (dispatch_test+0x4bb182) #7 _setup /builds/isc-projects/bind9/lib/dns/tests/dispatch_test.c:53:11 (dispatch_test+0x4b9ff8) #8 (libcmocka.so.0+0x51e2) #9 __libc_start_main /build/glibc-vjB4T1/glibc-2.28/csu/../csu/libc-start.c:308:16 (libc.so.6+0x2409a) SUMMARY: ThreadSanitizer: data race /builds/isc-projects/bind9/lib/isc/unix/socket.c:3012:34 in socket_create Conflict: NA Reference: https://gitlab.isc.org/isc-projects/bind9/-/commit/9b663419711ee2beb92c1c34a79669b251e7562d --- lib/isc/unix/socket.c | 7 ++++++- 1 file changed, 6 insertions(+), 1 deletion(-) diff --git a/lib/isc/unix/socket.c b/lib/isc/unix/socket.c index 219f4e3f92..2b034d1762 100644 --- a/lib/isc/unix/socket.c +++ b/lib/isc/unix/socket.c @@ -957,14 +957,17 @@ watch_fd(isc__socketmgr_t *manager, int fd, int msg) { uint32_t oldevents; int ret; int op; + int lockid = FDLOCK_ID(fd); oldevents = manager->epoll_events[fd]; + LOCK(&manager->fdlock[lockid]); if (msg == SELECT_POKE_READ) manager->epoll_events[fd] |= EPOLLIN; else manager->epoll_events[fd] |= EPOLLOUT; event.events = manager->epoll_events[fd]; + UNLOCK(&manager->fdlock[lockid]); memset(&event.data, 0, sizeof(event.data)); event.data.fd = fd; @@ -1036,13 +1039,15 @@ unwatch_fd(isc__socketmgr_t *manager, int fd, int msg) { struct epoll_event event; int ret; int op; + int lockid = FDLOCK_ID(fd); + LOCK(&manager->fdlock[lockid]); if (msg == SELECT_POKE_READ) manager->epoll_events[fd] &= ~(EPOLLIN); else manager->epoll_events[fd] &= ~(EPOLLOUT); - event.events = manager->epoll_events[fd]; + UNLOCK(&manager->fdlock[lockid]); memset(&event.data, 0, sizeof(event.data)); event.data.fd = fd; -- 2.23.0