Re: kern/56900 (panic in uvm_map_findspace)

[Taylor R Campbell <riastradh%NetBSD.org@localhost>]

> Date: Fri, 25 Nov 2022 22:55:59 +0900
> From: Rin Okuyama <rokuyama.rk%gmail.com@localhost>
> 
> Unfortunately, similar panic still takes place on sh3.
> Seems like something wrong in sh3/pmap...
> 
> ----
> # cd /usr/tests && atf-run | atf-report
> ...
> bin/sh/t_here (17/926): 11 test cases
>      do_simple: [9.487045s] Passed.
>      end_markers: [ 2036.0781860] panic: kernel diagnostic assertion "!topdown || hint <= orig_hint" failed: file "../../../../uvm/uvm_map.c", line 1795 map=0x8fe48d68 hint=0x7defb000 orig_hint=0x75172000 length=0x1000 uobj=0x8fd5eaa0 uoffset=0 align=0 flags=0x101 entry=0x8dfc6864 (uvm_map_findspace line 2011)

I think this is a different problem with a similar symptom, tracked in
PR kern/51254.  The issue that wiz hit with openjdk appears to have
been arithmetic wraparound with a length larger than the orig_hint
address -- and that's what the reproducer I posted triggers.

What you're seeing on sh3 appears to be different: small length, but
hint nevertheless ends up larger than orig_hint.

Can you get into ddb when this happens?  Can you do:

db> show map/f 0x8fe48d68

or whatever the `map=0x...' address is in the panic message, and
follow up on PR kern/51254 with the output?