Don't grab all the adb locks at once

FATAL: ThreadSanitizer CHECK failed: /build/llvm-toolchain-10-10.0.1~++20200708124224+ef32c611aa2/compiler-rt/lib/sanitizer_common/sanitizer_deadlock_detector.h:67 "((n_all_locks_)) < (((sizeof(all_locks_with_contexts_)/sizeof((all_locks_with_contexts_)[0]))))" (0x40, 0x40)
    #0 __tsan::TsanCheckFailed(char const*, int, char const*, unsigned long long, unsigned long long) <null> (named+0x4ad775)
    #1 __sanitizer::CheckFailed(char const*, int, char const*, unsigned long long, unsigned long long) <null> (named+0x4c429f)
    #2 __sanitizer::DeadlockDetectorTLS<__sanitizer::TwoLevelBitVector<1ul, __sanitizer::BasicBitVector<unsigned long> > >::addLock(unsigned long, unsigned long, unsigned int) <null> (named+0x4b8a3c)
    #3 __sanitizer::DD::MutexAfterLock(__sanitizer::DDCallback*, __sanitizer::DDMutex*, bool, bool) <null> (named+0x4b7fae)
    #4 __tsan::MutexPostLock(__tsan::ThreadState*, unsigned long, unsigned long, unsigned int, int) <null> (named+0x4abc58)
    #5 pthread_mutex_lock <null> (named+0x4643a8)
    #6 dump_adb /builds/isc-projects/bind9/lib/dns/adb.c:3461:3 (libdns.so.1110+0x48be6)
    #7 dns_adb_dump /builds/isc-projects/bind9/lib/dns/adb.c:3434:2 (libdns.so.1110+0x48738)
    #8 dumpdone /builds/isc-projects/bind9/bin/named/./server.c:10149:4 (named+0x512022)
    #9 dump_quantum /builds/isc-projects/bind9/lib/dns/masterdump.c:1424:2 (libdns.so.1110+0x9f253)
    #10 dispatch /builds/isc-projects/bind9/lib/isc/task.c:1157:7 (libisc.so.1107+0x50845)
    #11 run /builds/isc-projects/bind9/lib/isc/task.c:1331:2 (libisc.so.1107+0x4d799)
    #12 __tsan_thread_start_func <null> (named+0x446e3c)
    #13 start_thread /build/glibc-vjB4T1/glibc-2.28/nptl/pthread_create.c:486:8 (libpthread.so.0+0x7fa2)
    #14 clone /build/glibc-vjB4T1/glibc-2.28/misc/../sysdeps/unix/sysv/linux/x86_64/clone.S:95 (libc.so.6+0xf94ce)

diff --git a/lib/dns/adb.c b/lib/dns/adb.c
index d6f56fa6d393369335e936c26929912434a43521..982aba4cbf953448e3fd8dd39494ea72a96a538f 100644 (file)
--- a/lib/dns/adb.c
+++ b/lib/dns/adb.c
@@ -3457,18 +3457,16 @@ dump_adb(dns_adb_t *adb, FILE *f, bool debug, isc_stdtime_t now) {
                        adb, adb->erefcnt, adb->irefcnt,
                        isc_mempool_getallocated(adb->nhmp));
 
-       for (i = 0; i < adb->nnames; i++)
-               LOCK(&adb->namelocks[i]);
-       for (i = 0; i < adb->nentries; i++)
-               LOCK(&adb->entrylocks[i]);
-
        /*
         * Dump the names
         */
        for (i = 0; i < adb->nnames; i++) {
+               LOCK(&adb->namelocks[i]);
                name = ISC_LIST_HEAD(adb->names[i]);
-               if (name == NULL)
+               if (name == NULL) {
+                       UNLOCK(&adb->namelocks[i]);
                        continue;
+               }
                if (debug)
                        fprintf(f, "; bucket %u\n", i);
                for (;
@@ -3506,26 +3504,21 @@ dump_adb(dns_adb_t *adb, FILE *f, bool debug, isc_stdtime_t now) {
                                print_find_list(f, name);
                        }
                }
+               UNLOCK(&adb->namelocks[i]);
        }
 
        fprintf(f, ";\n; Unassociated entries\n;\n");
 
        for (i = 0; i < adb->nentries; i++) {
+               LOCK(&adb->entrylocks[i]);
                entry = ISC_LIST_HEAD(adb->entries[i]);
                while (entry != NULL) {
                        if (entry->nh == 0)
                                dump_entry(f, adb, entry, debug, now);
                        entry = ISC_LIST_NEXT(entry, plink);
                }
-       }
-
-       /*
-        * Unlock everything
-        */
-       for (i = 0; i < adb->nentries; i++)
                UNLOCK(&adb->entrylocks[i]);
-       for (i = 0; i < adb->nnames; i++)
-               UNLOCK(&adb->namelocks[i]);
+       }
 }
 
 static void
@@ -3644,6 +3637,7 @@ print_namehook_list(FILE *f, const char *legend,
                    dns_adb_t *adb, dns_adbnamehooklist_t *list,
                    bool debug, isc_stdtime_t now)
 {
+       int addr_bucket = DNS_ADB_INVALIDBUCKET;
        dns_adbnamehook_t *nh;
 
        for (nh = ISC_LIST_HEAD(*list);
@@ -3652,8 +3646,19 @@ print_namehook_list(FILE *f, const char *legend,
        {
                if (debug)
                        fprintf(f, ";\tHook(%s) %p\n", legend, nh);
+               if (addr_bucket != nh->entry->lock_bucket) {
+                       if (addr_bucket != DNS_ADB_INVALIDBUCKET) {
+                               UNLOCK(&adb->entrylocks[addr_bucket]);
+                       }
+                       addr_bucket = nh->entry->lock_bucket;
+                       INSIST(addr_bucket != DNS_ADB_INVALIDBUCKET);
+                       LOCK(&adb->entrylocks[addr_bucket]);
+               }
                dump_entry(f, adb, nh->entry, debug, now);
        }
+       if (addr_bucket != DNS_ADB_INVALIDBUCKET) {
+               UNLOCK(&adb->entrylocks[addr_bucket]);
+       }
 }
 
 static inline void