Panic in uvm_map_findspace (was Re: 9.99.98: spontaneous reboots)

[Thomas Klausner <wiz%NetBSD.org@localhost>]

> On 23.06.2022, at 09:34, Thomas Klausner <wiz%NetBSD.org@localhost> wrote:
> 
> On Tue, Jun 21, 2022 at 11:04:03PM +0200, Thomas Klausner wrote:
>> I've been running a 9.99.97 kernel from June 1 and it was stable,
>> including bulk builds. Today I upgraded to 9.99.98 and started a fresh
>> bulk build, and it rebooted after a couple hours, nothing in dmesg or
>> syslog, no crashdump.
>> 
>> I restarted the bulk build and it rebooted again after about 5 minutes
>> and one finished package. I think it was building nodejs and
>> webkit-gtk at the time (and some third package I don't know).
>> 
>> Has anyone else seen stability issues with today's current?
> 
> Thanks for the feedback.
> 
> I think you were lucky :) or we have different hardware.
> 
> I've tried bulk building with 98 for a third time and had a reboot
> shortly afterwards. Going back to 97 from June 1, I could finish a
> bulk build.
> 
> I've locally backed out the uvm changes from early June and will
> report back if that brought back stability.
> 

With the UVM changes from early June backed out, the system was stable.
I had ddb_onpanic=0, I switched to ddb_onpanic=1 and after some time with a 9.99.98 kernel I got this:

panic: kernel diagnostic assertion “!topdown || hint <= orig_hint” failed: file “/usr/src/sys/uvm/uvm_map.c”, line 1795 map=0xffffc8415a1d9388 hint=0xfffffff944a00000 orig_hint=0x82000000 length=0x77e000000 uobj=0x0 uoffset=0xfffffffffffffffff align=0 flags=0x80710 entry=0xffffc8415a1d93e0 (uvm_map_findspace line 1998)
cpu0: begin traceback
vpanic()
kern_assert()
uvm_findspace_invariants() at netbsd:uvm_findspace_invariants+0x83
uvm_map_findspace() at netbsd:uvm_map_findspace()+0x1c6
uvm_map_prepare() at netbsd:uvm_map_prepare+0x1f6
uvm_map() at netbsd:uvm_map+0x70
uvm_mmap.part.0() at netbsd:vm_mmap.part.0+0x15a
sys_mmap() at netbsd:sys_mmap+0x42f
syscall() number 197

(Handcopied with autocorrection, but I have pictures if you want to verify something).

 Thomas