hostapd segfault, unable to restart, unable to compile 2.0

[Norman Henderson]

Hi, I used hostapd happily for several years on voyage linux but have
just "upgraded" ?! to Ubuntu  Lucid 10.04 LTS and a custom kernel
2.6.32.61.

hostapd 0.6.9 periodically dies with "segfault at 0 ip 080a335d sp
bf8aa810 error 4 in hostapd [8048000+a6000]" (sp value varies). It
then doesn't authenticate my laptop anymore.

I am then unable to restart without rebooting: Running hostapd from
the console with -dd I get:
Configuration file: /etc/hostapd/hostapd.conf
ctrl_interface_group=0
ioctl[SIOCGIFFLAGS] No such device
Could not read interface flags (wlan0)
nl80211 driver initialization failed
wlan0: Unable to set up interface
rmdir[ctrl_interface]: No such file or directory

Hardware is Alix 3D3 with CM9-GP 802.11a/b/g wifi card. /etc/modules
includes ath9k (as an experiment which had no noticable effect, I
tried blacklisting ath5k).

When I reboot, all is OK - for an hour or so, then it segfaults and dies again.

SECOND ISSUE:
Seeing the version 0.6.9 is old I downloaded 2.0, created .config
(only removed radius accounting, otherwise = defconfig), and ran make
all. It gives many warnings and errors for
../src/drivers/driver_nl80211.c.

The kernel build included MAC80211, LIB80211 CFG80211, and the
parameter CONFIG_NL80211_TESTMODE=y (not sure why or what it means,
but for the record).

I don't have much experience installing software from scratch so I
really don't know where to go from here. Help - thank you in advance!

Norm Henderson