+diff -urN db-4.7.25.NC/lock/lock_deadlock.c db-4.7.25.NC.new/lock/lock_deadlock.c
+--- db-4.7.25.NC/lock/lock_deadlock.c 2008-03-10 14:31:33.000000000 +0100
++++ db-4.7.25.NC.new/lock/lock_deadlock.c 2009-11-08 12:53:25.000000000 +0100
+@@ -121,7 +121,7 @@
+ DB_LOCKTAB *lt;
+ db_timespec now;
+ locker_info *idmap;
+- u_int32_t *bitmap, *copymap, **deadp, **free_me, *tmpmap;
++ u_int32_t *bitmap, *copymap, **deadp, **deadlist, *tmpmap;
+ u_int32_t i, cid, keeper, killid, limit, nalloc, nlockers;
+ u_int32_t lock_max, txn_max;
+ int ret, status;
+@@ -133,7 +133,8 @@
+ if (IS_REP_CLIENT(env))
+ atype = DB_LOCK_MINWRITE;
+
+- free_me = NULL;
++ copymap = tmpmap = NULL;
++ deadlist = NULL;
+
+ lt = env->lk_handle;
+ if (rejectp != NULL)
+@@ -179,11 +180,11 @@
+ memcpy(copymap, bitmap, nlockers * sizeof(u_int32_t) * nalloc);
+
+ if ((ret = __os_calloc(env, sizeof(u_int32_t), nalloc, &tmpmap)) != 0)
+- goto err1;
++ goto err;
+
+ /* Find a deadlock. */
+ if ((ret =
+- __dd_find(env, bitmap, idmap, nlockers, nalloc, &deadp)) != 0)
++ __dd_find(env, bitmap, idmap, nlockers, nalloc, &deadlist)) != 0)
+ return (ret);
+
+ /*
+@@ -204,8 +205,7 @@
+ txn_max = TXN_MAXIMUM;
+
+ killid = BAD_KILLID;
+- free_me = deadp;
+- for (; *deadp != NULL; deadp++) {
++ for (deadp = deadlist; *deadp != NULL; deadp++) {
+ if (rejectp != NULL)
+ ++*rejectp;
+ killid = (u_int32_t)(*deadp - bitmap) / nalloc;
+@@ -342,11 +342,12 @@
+ __db_msg(env,
+ "Aborting locker %lx", (u_long)idmap[killid].id);
+ }
+- __os_free(env, tmpmap);
+-err1: __os_free(env, copymap);
+-
+-err: if (free_me != NULL)
+- __os_free(env, free_me);
++err: if(copymap != NULL)
++ __os_free(env, copymap);
++ if (deadlist != NULL)
++ __os_free(env, deadlist);
++ if(tmpmap != NULL)
++ __os_free(env, tmpmap);
+ __os_free(env, bitmap);
+ __os_free(env, idmap);
+
+@@ -360,6 +361,17 @@
+
+ #define DD_INVALID_ID ((u_int32_t) -1)
+
++/*
++ * __dd_build --
++ * Build the lock dependency bit maps.
++ * Notes on syncronization:
++ * LOCK_SYSTEM_LOCK is used to hold objects locked when we have
++ * a single partition.
++ * LOCK_LOCKERS is held while we are walking the lockers list and
++ * to single thread the use of lockerp->dd_id.
++ * LOCK_DD protects the DD list of objects.
++ */
++
+ static int
+ __dd_build(env, atype, bmp, nlockers, allocp, idmap, rejectp)
+ ENV *env;
+@@ -393,6 +405,7 @@
+ * In particular we do not build the conflict array and our caller
+ * needs to expect this.
+ */
++ LOCK_SYSTEM_LOCK(lt, region);
+ if (atype == DB_LOCK_EXPIRE) {
+ skip: LOCK_DD(env, region);
+ op = SH_TAILQ_FIRST(®ion->dd_objs, __db_lockobj);
+@@ -430,17 +443,18 @@
+ OBJECT_UNLOCK(lt, region, indx);
+ }
+ UNLOCK_DD(env, region);
++ LOCK_SYSTEM_UNLOCK(lt, region);
+ goto done;
+ }
+
+ /*
+- * We'll check how many lockers there are, add a few more in for
+- * good measure and then allocate all the structures. Then we'll
+- * verify that we have enough room when we go back in and get the
+- * mutex the second time.
++ * Allocate after locking the region
++ * to make sure the structures are large enough.
+ */
+-retry: count = region->stat.st_nlockers;
++ LOCK_LOCKERS(env, region);
++ count = region->stat.st_nlockers;
+ if (count == 0) {
++ UNLOCK_LOCKERS(env, region);
+ *nlockers = 0;
+ return (0);
+ }
+@@ -448,50 +462,37 @@
+ if (FLD_ISSET(env->dbenv->verbose, DB_VERB_DEADLOCK))
+ __db_msg(env, "%lu lockers", (u_long)count);
+
+- count += 20;
+ nentries = (u_int32_t)DB_ALIGN(count, 32) / 32;
+
+- /*
+- * Allocate enough space for a count by count bitmap matrix.
+- *
+- * XXX
+- * We can probably save the malloc's between iterations just
+- * reallocing if necessary because count grew by too much.
+- */
++ /* Allocate enough space for a count by count bitmap matrix. */
+ if ((ret = __os_calloc(env, (size_t)count,
+- sizeof(u_int32_t) * nentries, &bitmap)) != 0)
++ sizeof(u_int32_t) * nentries, &bitmap)) != 0) {
++ UNLOCK_LOCKERS(env, region);
+ return (ret);
++ }
+
+ if ((ret = __os_calloc(env,
+ sizeof(u_int32_t), nentries, &tmpmap)) != 0) {
++ UNLOCK_LOCKERS(env, region);
+ __os_free(env, bitmap);
+ return (ret);
+ }
+
+ if ((ret = __os_calloc(env,
+ (size_t)count, sizeof(locker_info), &id_array)) != 0) {
++ UNLOCK_LOCKERS(env, region);
+ __os_free(env, bitmap);
+ __os_free(env, tmpmap);
+ return (ret);
+ }
+
+ /*
+- * Now go back in and actually fill in the matrix.
+- */
+- if (region->stat.st_nlockers > count) {
+- __os_free(env, bitmap);
+- __os_free(env, tmpmap);
+- __os_free(env, id_array);
+- goto retry;
+- }
+-
+- /*
+ * First we go through and assign each locker a deadlock detector id.
+ */
+ id = 0;
+- LOCK_LOCKERS(env, region);
+ SH_TAILQ_FOREACH(lip, ®ion->lockers, ulinks, __db_locker) {
+ if (lip->master_locker == INVALID_ROFF) {
++ DB_ASSERT(env, id < count);
+ lip->dd_id = id++;
+ id_array[lip->dd_id].id = lip->id;
+ switch (atype) {
+@@ -510,7 +511,6 @@
+ lip->dd_id = DD_INVALID_ID;
+
+ }
+- UNLOCK_LOCKERS(env, region);
+
+ /*
+ * We only need consider objects that have waiters, so we use
+@@ -669,7 +669,6 @@
+ * status after building the bit maps so that we will not detect
+ * a blocked transaction without noting that it is already aborting.
+ */
+- LOCK_LOCKERS(env, region);
+ for (id = 0; id < count; id++) {
+ if (!id_array[id].valid)
+ continue;
+@@ -738,6 +737,7 @@
+ id_array[id].in_abort = 1;
+ }
+ UNLOCK_LOCKERS(env, region);
++ LOCK_SYSTEM_UNLOCK(lt, region);
+
+ /*
+ * Now we can release everything except the bitmap matrix that we
+@@ -839,6 +839,7 @@
+ ret = 0;
+
+ /* We must lock so this locker cannot go away while we abort it. */
++ LOCK_SYSTEM_LOCK(lt, region);
+ LOCK_LOCKERS(env, region);
+
+ /*
+@@ -895,6 +896,7 @@
+ done: OBJECT_UNLOCK(lt, region, info->last_ndx);
+ err:
+ out: UNLOCK_LOCKERS(env, region);
++ LOCK_SYSTEM_UNLOCK(lt, region);
+ return (ret);
+ }
+
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