Re: panic: object has cached pages on recent HEAD

On  6 Apr, To: current_at_freebsd.org wrote:
> I just got this panic on my port builder machine running a recent
> version of HEAD (last updated in the last few days):
> 
> panic: object has cached pages on recent HEAD
> 
> As you can see, I was pushing it really hard:
> 
> last pid: 76867;  load averages: 62.92, 41.93, 41.40    up 7+10:24:04  13:45:01
> 448 processes: 97 running, 344 sleeping, 7 stopped
> CPU: 79.1% user,  0.0% nice, 20.9% system,  0.0% interrupt,  0.0% idle
> Mem: 5887M Active, 163M Inact, 6085M Wired, 17M Cache, 832K Buf, 3658M Free
> ARC: 1482M Total, 163M MFU, 663M MRU, 7080K Anon, 70M Header, 579M Other
> Swap: 40G Total, 9167M Used, 31G Free, 22% Inuse, 1152K In
> 
>   PID USERNAME    THR PRI NICE   SIZE    RES STATE   C   TIME    WCPU COMMAND
> 73630 root          1  77    0   195M   181M CPU5    5   0:06  37.28% cc1plus
> 75387 root          1  78    0   209M   193M RUN     2   0:06  36.60% cc1plus
> 75615 root          1  74    0   150M   133M RUN     7   0:04  36.20% cc1plus
> 74151 root          1  78    0   306M   290M RUN     0   0:12  31.77% cc1plus
> 72986 root          1  78    0   282M   264M RUN     5   0:19  30.24% cc1plus
> 72985 root          1  77    0   292M   272M RUN     1   0:18  28.00% cc1plus
> 75912 root          1  75    0   106M 97604K RUN     3   0:03  27.73% cc1plus
> 74501 root          1  80    0   293M   280M RUN     7   0:11  27.14% cc1plus
> 73442 root          1  77    0   329M   299M RUN     2   0:13  26.54% cc1plus
> 75715 root          1  75    0 96996K 81424K RUN     3   0:02  22.51% cc1plus
> 74645 root          1  78    0   252M   236M RUN     6   0:09  21.73% cc1plus
> 75630 root          1  77    0   208M   189M RUN     4   0:08  19.27% cc1plus
> 74324 root          1  78    0   322M   308M RUN     4   0:11  19.17% cc1plus
> 75494 root          1  74    0   138M   126M RUN     4   0:04  19.07% cc1plus
> 74848 root          1  73    0 98180K 85192K RUN     2   0:02  16.12% cc1plus
> 76292 root          1  73    0 63108K 46904K RUN     0   0:01  15.92% cc1plus
> 
> A screenshot with a backtrace is here:
> <https://people.freebsd.org/~truckman/panic_object_has_cached_pages.jpg>
> 
> Is there anything I should check in DDB before I reboot?  I can get the
> svn revision after I do that.
> 
> I've never crashed this machine before, so I don't know if crashdumps
> work.

I was able to call doadump() from ddb, but when I rebooted, savecore was
not able to find the dump.  I dumped to swap, which is mirrored ...

FreeBSD zipper.catspoiler.org 11.0-CURRENT FreeBSD 11.0-CURRENT #13
r280327M: Sun Mar 29 22:26:50 PDT 2015

I am running with this custom patch so that pre-compiled headers work
with gcc:

Index: sys/vm/vm_mmap.c
===================================================================
--- sys/vm/vm_mmap.c	(revision 280837)
+++ sys/vm/vm_mmap.c	(working copy)
_at__at_ -325,6 +325,8 _at__at_
 		 * There should really be a pmap call to determine a reasonable
 		 * location.
 		 */
+		if (addr != 0 && (flags & MAP_ANON) == 0)
+			flags |= MAP_RESERVED0100;
 		PROC_LOCK(td->td_proc);
 		if (addr == 0 ||
 		    (addr >= round_page((vm_offset_t)vms->vm_taddr) &&
_at__at_ -1665,6 +1667,8 _at__at_
 		else if ((flags & MAP_ALIGNMENT_MASK) != 0)
 			findspace = VMFS_ALIGNED_SPACE(flags >>
 			    MAP_ALIGNMENT_SHIFT);
+		else if ((flags & MAP_RESERVED0100) != 0)
+			findspace = VMFS_ANY_SPACE;
 		else
 			findspace = VMFS_OPTIMAL_SPACE;
 		rv = vm_map_find(map, object, foff, addr, size,