On Thu, Mar 08 2007, Andre Noll wrote:
> On 10:36, Jens Axboe wrote:
> > - Edit .config and set CONFIG_DEBUG_INFO=y (near the bottom)
> > - make oldconfig
> > - rm block/cfq-iosched.o
> > - make block/cfq-iosched.o
> > - gdb block/cfq-iosched.o
> >
> > (gdb) l *cfq_dispatch_insert+0x28
> >
> > and see what that says. Should not take you more than a minute or so,
> > would appreciate it!
>
> No problem, here we go:
>
> # gdb block/cfq-iosched.o
> GNU gdb 6.4-debian
> Copyright 2005 Free Software Foundation, Inc.
> GDB is free software, covered by the GNU General Public License, and you are
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> This GDB was configured as "x86_64-linux-gnu"...Using host libthread_db library "/lib/libthread_db.so.1".
>
> (gdb) l *cfq_dispatch_insert+0x28
> 0xcf8 is in cfq_dispatch_insert (block/cfq-iosched.c:865).
> 860 }
> 861
> 862 static void cfq_dispatch_insert(request_queue_t *q, struct request *rq)
> 863 {
> 864 struct cfq_data *cfqd = q->elevator->elevator_data;
> 865 struct cfq_queue *cfqq = RQ_CFQQ(rq);
> 866
> 867 cfq_remove_request(rq);
> 868 cfqq->on_dispatch[rq_is_sync(rq)]++;
> 869 elv_dispatch_sort(q, rq);
Ok, so it's ->next_rq being NULL or invalid. Similar to the report from
Dan last week, that's a bit worrisome. I'll have to look further into
that.
--
Jens Axboe
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