Winbindd dies when running "getent group" on a PDC based on Samba 3.2.4 with
"ldapsam:editposix" enabled (see attachments).
The crash of Winbindd happens when getent tries to enumerate the users members of a group
where there are computer accounts (like "domain users" group).

I think it's a problem of "sam_lookup_groupmem", in "winbindd_passdb.c", that do not sets properly the pointers in 
"**name_types" and "***names" (the concept also applies to Samba 3.3.0pre2, I think)

I propose the attached patch ("winbindd_passdb.patch")

--- winbindd_passdb.c	2008-09-18 08:49:02.000000000 +0200
+++ Pwinbindd_passdb.c	2008-11-16 17:33:06.000000000 +0100
@@ -638,13 +638,13 @@ static NTSTATUS sam_lookup_groupmem(stru
 				  sid_type_lookup(lsa_names[i].type)));
 			continue;
 		}
-		if (!((*names)[i] = talloc_strdup((*names),
+		if (!((*names)[num_mapped] = talloc_strdup((*names),
 						  lsa_names[i].name))) {
 			TALLOC_FREE(tmp_ctx);
 			return NT_STATUS_NO_MEMORY;
 		}
 
-		(*name_types)[i] = lsa_names[i].type;
+		(*name_types)[num_mapped] = lsa_names[i].type;
 
 		num_mapped += 1;
 	}

The tests were performed on Debian Lenny, with
 Linux 2.6.26/2.6.27.4  (compiled from source)
 openldap-2.4.11        (compiled from source)
 nss_ldap-263           (compiled from source)
 Samba 3.2.4            (compiled from source)

Regards,
Davide Sfriso.
PS: I'm sorry for my bad english.