[En-Nut-Discussion] Problem with Timers

[Waschk,Kolja]

Hi

I'm currently hunting for anything that is causing "almost deterministic"
lockups of my target. In that state it won't even answer ICMP echo reqs.
When interrupted (with avr-gdb / JTAG), gdb most of the time says the
interruption occured during NutTimerInsert or some other code in my app
that internally is going to use a timer (NutEventWait or similar). So I'm
peeking aroung the timer data and code.

What I'm wondering is the nutTimerList gdb presents me. Is it okay if it
contains self-referencing items, i.e. where tnp == tnp->tn_next? After I
put in a real dirty hack to cancel exactly this situation, it came up with
referencing loops like shown here:

Program received signal SIGINT, Interrupt.
0x0000aa56 in NutTimerInsert (tn=0x80317c) at timer.c:169
169             if (tn->tn_ticks_left < tnp->tn_ticks_left) {
(gdb) print tnp
$1 = (NUTTIMERINFO *) 0x801825
(gdb) print tnp->tn_next
$2 = (NUTTIMERINFO *) 0x80317c
(gdb) print tnp->tn_next->tn_next
$3 = (NUTTIMERINFO *) 0x801825   (note: same as $1)
(gdb) print tnp->tn_next->tn_next->tn_next
$4 = (NUTTIMERINFO *) 0x80317c   (naturally, same as $2)


BTW, saying "almost deterministic" just means that it almost always occurs
at about the same time after starting a certain test procedure that causes
quite a lot of activity. That's about 5 minutes however. Only a few times
it occured a lot earlier.

Kolja

-- 
mr. kolja waschk - haubach-39 - 22765 hh - ger
phone +49 40 889130-34 - fax -35 - e-mail s.a.