strange segfault with 8.3.8

hello,

from kernel log:

Dec 7 07:24:45 nsXXXXXX kernel: postgres[22481]: segfault at 7fda5e1d5000
ip 00007fda604553c3 sp 00007fffe41faf28 error 4 in libc-2.9.so
[7fda603d1000+168000]
Dec 7 07:24:45 nsXXXXXX kernel: grsec: From XX.YY.ZZ.51: Segmentation fault
occurred at 00007fda5e1d5000 in
/usr/lib/postgresql/8.3/bin/postgres[postgres:22481] uid/euid:103/103
gid/egid:114/114, parent
/usr/lib/postgresql/8.3/bin/postgres[postgres:29857] uid/euid:103/103
gid/egid:114/114

This is on 8.3.8, latest Ubuntu distribution, server under quite heavy load.

afterwards we had some corrupted pages ("*ERROR: compressed data is corrupt*
").

any clues / directions welcome.

--
Filip Rembiałkowski
JID,mailto:filip(dot)rembialkowski(at)gmail(dot)com
http://filip.rembialkowski.net/