Date: Fri, 04 Nov 2005 01:18:54 +0600 From: Victor Snezhko <snezhko@indorsoft.ru> To: freebsd-current@freebsd.org Subject: [SOLVED] kgdb strange behaviour on current Message-ID: <uirv9v8td.fsf@indorsoft.ru> In-Reply-To: <uek5y6y9d.fsf@indorsoft.ru> (Victor Snezhko's message of "Thu, 03 Nov 2005 12:28:30 %2B0600") References: <uek5y6y9d.fsf@indorsoft.ru>
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Victor Snezhko <snezhko@indorsoft.ru> writes:
> (kgdb) list
> 215 curticks = softticks;
> 216 bucket = &callwheel[curticks & callwheelmask];
> 217 c = TAILQ_FIRST(bucket);
> 218 while (c) {
> 219 depth++;
> 220 if (c->c_time != curticks) {
> 221 c = TAILQ_NEXT(c, c_links.tqe);
> 222 ++steps;
> 223 if (steps >= MAX_SOFTCLOCK_STEPS) {
> 224 nextsoftcheck = c;
> (kgdb) print c
> $1 = (struct callout *) 0xdeadc0de
> (kgdb) print bucket->tqh_first
> $2 = (struct callout *) 0xc18eb520
> (kgdb) print *(bucket->tqh_first)
> $3 = {c_links = {sle = {sle_next = 0xdeadc0de}, tqe = {tqe_next = 0xdeadc0de,
> tqe_prev = 0xdeadc0de}}, c_time = -559038242, c_arg = 0xdeadc0de,
> c_func = 0xdeadc0de, c_mtx = 0xdeadc0de, c_flags = -559038242}
> (kgdb) print bucket
> $4 = (struct callout_tailq *) 0xc66021e8
> (kgdb) quit
>
> /home/vvs # grep "#define.*[^S]TAILQ_FIRST" /usr/src/sys/sys/queue.h
> #define TAILQ_FIRST(head) ((head)->tqh_first)
>
> bucket->tqh_first seems to be a valid pointer, but points to
> garbage. But c should be the same pointer, and debugger shows a
> distinct value for it!
kgdb works fine, I misunderstood the moment of time when
crash occured.
--
WBR, Victor V. Snezhko
EMail: snezhko@indorsoft.ru
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