It seems that I fall in this bug. amavisd-new/Spamassassin make use of regexp (yes, spamassassin via perl).Anyway, my memory becomes rapidely full on my mail relay (sarge + postfix + amavisd-new + spamassassin + dcc-client + razor2 + pyzor + sophie + clamav). The packages are from sarge except amavisd-new, spamassassin and clamav from backports.org.