different behavior of socket()/setsocketopt()/poll() in chroot?

[ipif]

Hi,

I'm still coping with my embedded sparc system. After having applied lots of
patches and fixed several system calls (I promise to post them soon) I'm now
evaluating the mini_fo overlay filesystem. With this, the whole system runs
in a chroot environment. Everything seems to work fine, but ntpdate does not
run properly any more. As I run the same binary in both environments I
assume that this is more a system related issue.
For the chroot environment I use the following script as init, the rest is
identical:

mount -t tmpfs -o rw,size=32M none ${MOUNT_OVERLAY}
mount -t mini_fo -o base=/,sto=${MOUNT_OVERLAY} / ${MOUNT_ROOT}
exec chroot ${MOUNT_ROOT} /sbin/init

Running strace the initial parts are identical:
# strace ntpdate -u <server>
[...]
socket(PF_INET, SOCK_DGRAM, IPPROTO_UDP) = 3
setsockopt(3, SOL_SOCKET, SO_REUSEADDR, [1], 4) = 0
fcntl(3, F_SETFL, O_RDONLY|O_NONBLOCK)  = 0
rt_sigaction(SIGALRM, {0x11524, [], 0}, {SIG_DFL, [], 0}, 0x50026cf4, 4) = 0
setitimer(ITIMER_REAL, {it_interval={0, 200000}, it_value={0, 100000}},
NULL) = 0
setpriority(PRIO_PROCESS, 0, -12)       = 0

On the original system the following happens:
poll([{fd=3, events=POLLIN}], 1, 60000) = -1 EINTR (Interrupted system call)
--- SIGALRM (Alarm clock) @ 0 (0) ---
[...]
exit(0)                                 = ?

On the chrooted one:
poll([{fd=3, events=POLLIN}], 1, 60000) = 0 (Timeout)
[...]
poll([{fd=3, events=POLLIN}], 1, 60000) = 0 (Timeout)
[...]
and so on.

All other programs that rely on network connections (ssh, webserver, etc.)
run normally. Maybe it's related to poll().
I'm using uclibc-0.9.30 and linux-2.6.21.

Sorry, I've no idea if this is really uclibc related, but perhaps someone of
you can give me a hint how to debug this problem.

Thanks,
-jan
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