radius going to sleep?

[Norbert Wegener]

In a cvs version of pre2, which is newer than pre2, on one machine, 
after some time of inactivity, freeradius does not seem to answer at 
all- sometimes, not
reliable reproducable.
Freeradius has a lot of database connections to mysql, maybe they are 
the culprit for that behaviour? stracing freeradius  gives:
 # strace -f -p 29757
Process 29807 attached with 51 threads - interrupt to quit
[pid 29757] --- SIGSTOP (Stopped (signal)) @ 0 (0) ---
[pid 29758] --- SIGSTOP (Stopped (signal)) @ 0 (0) ---
[pid 29759] --- SIGSTOP (Stopped (signal)) @ 0 (0) ---
[pid 29760] --- SIGSTOP (Stopped (signal)) @ 0 (0) ---
[pid 29761] --- SIGSTOP (Stopped (signal)) @ 0 (0) ---
...

[pid 29796] --- SIGSTOP (Stopped (signal)) @ 0 (0) ---
[pid 29797] --- SIGSTOP (Stopped (signal)) @ 0 (0) ---
[pid 29798] --- SIGSTOP (Stopped (signal)) @ 0 (0) ---
[pid 29799] --- SIGSTOP (Stopped (signal)) @ 0 (0) ---
[pid 29800] --- SIGSTOP (Stopped (signal)) @ 0 (0) ---
[pid 29801] --- SIGSTOP (Stopped (signal)) @ 0 (0) ---
[pid 29802] --- SIGSTOP (Stopped (signal)) @ 0 (0) ---
[pid 29803] --- SIGSTOP (Stopped (signal)) @ 0 (0) ---
---
[pid 29778] --- SIGSTOP (Stopped (signal)) @ 0 (0) ---
[pid 29779] --- SIGSTOP (Stopped (signal)) @ 0 (0) ---
[pid 29780] --- SIGSTOP (Stopped (signal)) @ 0 (0) ---
[pid 29781] --- SIGSTOP (Stopped (signal)) @ 0 (0) ---
[pid 29782] --- SIGSTOP (Stopped (signal)) @ 0 (0) ---
[pid 29783] --- SIGSTOP (Stopped (signal)) @ 0 (0) ---
[pid 29784] --- SIGSTOP (Stopped (signal)) @ 0 (0) ---
[pid 29785] --- SIGSTOP (Stopped (signal)) @ 0 (0) ---
[pid 29786] --- SIGSTOP (Stopped (signal)) @ 0 (0) ---
...
[pid 29803] --- SIGSTOP (Stopped (signal)) @ 0 (0) ---
[pid 29804] --- SIGSTOP (Stopped (signal)) @ 0 (0) ---
[pid 29805] --- SIGSTOP (Stopped (signal)) @ 0 (0) ---
[pid 29806] --- SIGSTOP (Stopped (signal)) @ 0 (0) ---
[pid 29807] --- SIGSTOP (Stopped (signal)) @ 0 (0) ---
[pid 29758] futex(0x8002f654, FUTEX_WAIT, 0, NULL <unfinished ...>
[pid 29759] futex(0x8002f654, FUTEX_WAIT, 0, NULL <unfinished ...>
[pid 29760] read(9,  <unfinished ...>
[pid 29761] read(8,  <unfinished ...>
[pid 29762] futex(0x8002f654, FUTEX_WAIT, 0, NULL <unfinished ...>
[pid 29763] futex(0x8002f654, FUTEX_WAIT, 0, NULL <unfinished ...>
[pid 29764] futex(0x8002f654, FUTEX_WAIT, 0, NULL <unfinished ...>
[pid 29765] futex(0x8002f654, FUTEX_WAIT, 0, NULL <unfinished ...>
[pid 29766] futex(0x8002f654, FUTEX_WAIT, 0, NULL <unfinished ...>
[.....
[pid 29798] futex(0x8002f654, FUTEX_WAIT, 0, NULL <unfinished ...>
[pid 29799] futex(0x8002f654, FUTEX_WAIT, 0, NULL <unfinished ...>
[pid 29800] futex(0x8002f654, FUTEX_WAIT, 0, NULL <unfinished ...>
[pid 29801] futex(0x8002f654, FUTEX_WAIT, 0, NULL <unfinished ...>
[pid 29802] futex(0x8002f654, FUTEX_WAIT, 0, NULL <unfinished ...>
[pid 29803] futex(0x8002f654, FUTEX_WAIT, 0, NULL <unfinished ...>
[pid 29804] futex(0x8002f654, FUTEX_WAIT, 0, NULL <unfinished ...>
[pid 29805] futex(0x8002f654, FUTEX_WAIT, 0, NULL <unfinished ...>
[pid 29806] futex(0x8002f654, FUTEX_WAIT, 0, NULL <unfinished ...>
[pid 29807] futex(0x8002f654, FUTEX_WAIT, 0, NULL


with a few dozens lines deleted.
strace's output stops here, also when radius request come in. They are 
not answered.
Any idea, what's going wrong here or how to track that down?
I already tried
nohup gdb -x gdbargs /sbin/radiusd &
with gdbargs containing:
run -AX
bt

but was unable to reproduce that situation in this context.
Running radiusd under gdb's control seemed to solve that problem, maybe 
that's not the final solution.

Norbert Wegener