Re: Panic during shutdown

On Wed, 1 Jul 2009, Kostik Belousov wrote:

>>     at /usr/src/sys/vm/vm_object.c:715
>> #6  0xc064d24c in vm_object_deallocate (object=0xc4300000)
>>     at /usr/src/sys/vm/vm_object.c:592
> I am interested in the output of
> p *object
> from the frame 6, and the output of
> p swap_total
> p swap_reserved
> all from kgdb.
>

...
(kgdb) frame 6
#6  0xc064d24c in vm_object_deallocate (object=0xc4300000)
     at /usr/src/sys/vm/vm_object.c:592
592                             vm_object_terminate(object);
(kgdb) list
587                      * Don't double-terminate, we could be in a termination
588                      * recursion due to the terminate having to sync data
589                      * to disk.
590                      */
591                     if ((object->flags & OBJ_DEAD) == 0)
592                             vm_object_terminate(object);
593                     else
594                             VM_OBJECT_UNLOCK(object);
595                     object = temp;
596             }
(kgdb) p *object
$1 = {mtx = {lock_object = {lo_name = 0xc06ce176 "vm object",
       lo_flags = 21168128, lo_data = 0, lo_witness = 0x0}, mtx_lock = 4},
   object_list = {tqe_next = 0xc43217f8, tqe_prev = 0xc41b1454}, shadow_head = {
     lh_first = 0x0}, shadow_list = {le_next = 0x0, le_prev = 0xc415c5f4},
   memq = {tqh_first = 0x0, tqh_last = 0xc4300028}, root = 0x0, size = 245,
   generation = 271, ref_count = 0, shadow_count = 0, type = 0 '\0',
   flags = 12552, pg_color = 250, paging_in_progress = 0,
   resident_page_count = 0, backing_object = 0x0, backing_object_offset = 0,
   pager_object_list = {tqe_next = 0x0, tqe_prev = 0x0}, rvq = {
     lh_first = 0x0}, cache = 0x0, handle = 0x0, un_pager = {vnp = {
       vnp_size = 0}, devp = {devp_pglist = {tqh_first = 0x0, tqh_last = 0x0}},
     swp = {swp_bcount = 0}}, uip = 0xc3d10340, charge = 1003520}
(kgdb) p swap_total
$2 = 2147483648
(kgdb) p swap_reserved
$3 = 634880


> Also, please describe the load on the machine,
>

It happens regardless of the load.  For example, just booting multi-user 
and immediately running shutdown (either by logging in or pressing the 
ACPI power button) triggers the panic.


> ... and look up what process exited when the panic happens.
>

The panic message on the console does not show the process.  Can that be 
determined from kgdb?  If so, how?


> Thanks for the report.
>

Thanks for looking into it!

-- 
Greg Rivers