diff --git a/src/H5Zconfig.c b/src/H5Zconfig.c
index 8fa9fc11604..cceb3f50e49 100644
--- a/src/H5Zconfig.c
+++ b/src/H5Zconfig.c
@@ -492,16 +492,16 @@ H5Zconfig_has_key(const char *params, const char *key)
     toml_datum_t  d;
     htri_t        ret_value = FAIL;
 
-    /* The API lock is recursive, so this is safe to call from inside an
-     * H5Z_set_config_func_t callback that is already running under the API
-     * lock held by H5Pappend_filter. */
-    FUNC_ENTER_API_NOINIT
+    /* No API lock: this is a pure parser over caller-provided buffers and
+     * may be called from inside an H5Z_set_config_func_t callback that is
+     * already running under the API lock held by H5Pappend_filter. */
+    FUNC_ENTER_API_NOINIT_NOLOCK
 
     ret_value = H5Z__config_get_datum(params, key, &tr, &d);
 
     if (ret_value > 0)
         toml_free(tr);
-    FUNC_LEAVE_API_NOINIT(ret_value)
+    FUNC_LEAVE_API_NOINIT_NOLOCK(ret_value)
 }
 
 /*-------------------------------------------------------------------------
@@ -578,12 +578,12 @@ H5Zconfig_get_int(const char *params, const char *key, int64_t *out)
 {
     htri_t ret_value = FAIL;
 
-    /* See comment on H5Zconfig_has_key about recursive re-entry. */
-    FUNC_ENTER_API_NOINIT
+    /* No API lock: see comment on H5Zconfig_has_key. */
+    FUNC_ENTER_API_NOINIT_NOLOCK
 
     ret_value = H5Z__config_get_int(params, key, out);
 
-    FUNC_LEAVE_API_NOINIT(ret_value)
+    FUNC_LEAVE_API_NOINIT_NOLOCK(ret_value)
 }
 
 /*-------------------------------------------------------------------------
@@ -606,8 +606,8 @@ H5Zconfig_get_double(const char *params, const char *key, double *out)
     htri_t        found;
     htri_t        ret_value = FAIL;
 
-    /* See comment on H5Zconfig_has_key about recursive re-entry. */
-    FUNC_ENTER_API_NOINIT
+    /* No API lock: see comment on H5Zconfig_has_key. */
+    FUNC_ENTER_API_NOINIT_NOLOCK
 
     if (!out)
         HGOTO_ERROR(H5E_ARGS, H5E_BADVALUE, FAIL, "out must not be NULL");
@@ -628,7 +628,7 @@ H5Zconfig_get_double(const char *params, const char *key, double *out)
 done:
     if (tr_valid)
         toml_free(tr);
-    FUNC_LEAVE_API_NOINIT(ret_value)
+    FUNC_LEAVE_API_NOINIT_NOLOCK(ret_value)
 }
 
 /*-------------------------------------------------------------------------
@@ -650,8 +650,8 @@ H5Zconfig_get_bool(const char *params, const char *key, bool *out)
     htri_t        found;
     htri_t        ret_value = FAIL;
 
-    /* See comment on H5Zconfig_has_key about recursive re-entry. */
-    FUNC_ENTER_API_NOINIT
+    /* No API lock: see comment on H5Zconfig_has_key. */
+    FUNC_ENTER_API_NOINIT_NOLOCK
 
     if (!out)
         HGOTO_ERROR(H5E_ARGS, H5E_BADVALUE, FAIL, "out must not be NULL");
@@ -669,7 +669,7 @@ H5Zconfig_get_bool(const char *params, const char *key, bool *out)
 done:
     if (tr_valid)
         toml_free(tr);
-    FUNC_LEAVE_API_NOINIT(ret_value)
+    FUNC_LEAVE_API_NOINIT_NOLOCK(ret_value)
 }
 
 /*-------------------------------------------------------------------------
@@ -763,10 +763,10 @@ H5Zconfig_get_str(const char *params, const char *key, char *buf, size_t *buf_si
 {
     htri_t ret_value = FAIL;
 
-    /* See comment on H5Zconfig_has_key about recursive re-entry. */
-    FUNC_ENTER_API_NOINIT
+    /* No API lock: see comment on H5Zconfig_has_key. */
+    FUNC_ENTER_API_NOINIT_NOLOCK
 
     ret_value = H5Z__config_get_str(params, key, buf, buf_size);
 
-    FUNC_LEAVE_API_NOINIT(ret_value)
+    FUNC_LEAVE_API_NOINIT_NOLOCK(ret_value)
 }
diff --git a/src/H5private.h b/src/H5private.h
index 141fc97aca7..b7d5d9c2551 100644
--- a/src/H5private.h
+++ b/src/H5private.h
@@ -1453,6 +1453,26 @@ extern char H5_lib_vers_info_g[];
                 H5_API_LOCK                                                                                  \
                 {
 
+/*
+ * Use this macro for public API functions that may be re-entered from inside
+ * a library callback that already holds the API lock (e.g. filter v3
+ * H5Z_set_config_func_t callbacks invoked from H5Pappend_filter).  Performs
+ * the same error-handling and function-name setup as FUNC_ENTER_API_NOINIT
+ * but skips H5_API_LOCK, so the function is safe to call while another
+ * public API frame already holds the lock.  Only appropriate for pure
+ * helpers that touch no global library state.  Examples: H5Zconfig_get_int,
+ * H5Zconfig_get_double, etc.
+ */
+#define FUNC_ENTER_API_NOINIT_NOLOCK                                                                         \
+    {                                                                                                        \
+        {                                                                                                    \
+            {                                                                                                \
+                H5_CHECK_FUNCTION_NAME(H5_IS_PUBLIC(__func__));                                              \
+                                                                                                             \
+                H5_API_SETUP_PUBLIC_API_VARS                                                                 \
+                H5_API_SETUP_ERROR_HANDLING                                                                  \
+                {
+
 /*
  * Use this macro for public API functions that shouldn't perform _any_
  * initialization of the library or an interface or push themselves on the
@@ -1676,6 +1696,17 @@ extern char H5_lib_vers_info_g[];
     }                                                                                                        \
     } /* end scope from beginning of FUNC_ENTER */
 
+/* Use this macro to match the FUNC_ENTER_API_NOINIT_NOLOCK macro */
+#define FUNC_LEAVE_API_NOINIT_NOLOCK(ret_value)                                                              \
+    ;                                                                                                        \
+    } /* end scope from end of FUNC_ENTER */                                                                 \
+    if (H5_UNLIKELY(err_occurred))                                                                           \
+        (void)H5E_dump_api_stack();                                                                          \
+    return (ret_value);                                                                                      \
+    }                                                                                                        \
+    }                                                                                                        \
+    } /* end scope from beginning of FUNC_ENTER */
+
 /* Use this macro to match the FUNC_ENTER_API_NOINIT_NOERR macro */
 #define FUNC_LEAVE_API_NOERR(ret_value)                                                                      \
     ;                                                                                                        \