I've finally found that this bug was reported as #4745 on http://sources.redhat.com/bugzilla/show_bug.cgi?id=4745 with a 'FIXED' status, I suppose that the patch is already included in glibc 2.6-2 I've tested in Sid.
What could be done for Sarge and Etch ?
with regards,
Frédéric.
