[BUG 2.5.X] Hollow processes

[=?ISO-8859-2?Q?Witek_Kr=EAcicki?=]

(Had the same problem on 2.5.9 with poldek, now it appeared on 2.5.15dj1
while building glibc-2.5.4 to rpm)
Process is hanging. It's impossible to stop it (even SAK is just clearing
console). It's impossible to check what the process is (trying to read
/proc/{pid}/{anyting} causes reading process to hang in the same way (so we
have now 2 hanging processes). Trying to use ps/lsof/killall/{anything that
is using /proc/{pid} causes this software hang in the same way. What could
it be?
WK