Apply Victor's suggestions

Co-authored-by: Victor Stinner <victor.stinner@gmail.com>

Author: StanFromIreland

.github/workflows/reusable-san.yml

@@ -72,7 +72,7 @@ jobs:
     - name: MSan option setup
       if: inputs.sanitizer == 'MSan'
       run: |
-        echo "MSAN_OPTIONS=${SAN_LOG_OPTION} allocator_may_return_null=1" >> "$GITHUB_ENV"
+        echo "MSAN_OPTIONS=${SAN_LOG_OPTION} allocator_may_return_null=1 handle_segv=0" >> "$GITHUB_ENV"
         # MSan reports false positives for memory initialized by libraries
         # that are not built with MSan, so disable modules that use them.
         # _remote_debugging links to libzstd directly, but we unpoision the memory.

Doc/using/configure.rst

@@ -1026,6 +1026,10 @@ Debug options
 
    Enable MemorySanitizer allocation error detector, ``msan`` (default is no).
 
+   MSan reports false positives for memory initialized by libraries that are
+   not built with MSan, so either build all dependencies with MSan or disable
+   the extension modules that use them in :file:`Modules/Setup.local`.
+
    .. versionadded:: 3.6
 
 .. option:: --with-undefined-behavior-sanitizer

configure

@@ -4458,7 +4458,7 @@ int main(void)
     {
         return 2;
     }
-    ffi_arg rc;
+    ffi_arg rc = 0;
     ffi_call(&cif, FFI_FN(z_is_expected), &rc, values);
     return !rc;
 }