Re: kern/56900 (panic in uvm_map_findspace)

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

The following reply was made to PR kern/56900; it has been noted by GNATS.

From: Taylor R Campbell <riastradh%NetBSD.org@localhost>
To: Rin Okuyama <rokuyama.rk%gmail.com@localhost>
Cc: gnats-bugs%netbsd.org@localhost, kern-bug-people%netbsd.org@localhost,
	netbsd-bugs%netbsd.org@localhost, gnats-admin%netbsd.org@localhost
Subject: Re: kern/56900 (panic in uvm_map_findspace)
Date: Fri, 25 Nov 2022 14:07:42 +0000

 > Date: Fri, 25 Nov 2022 22:55:59 +0900
 > From: Rin Okuyama <rokuyama.rk%gmail.com@localhost>
 >=20
 > Unfortunately, similar panic still takes place on sh3.
 > Seems like something wrong in sh3/pmap...
 >=20
 > ----
 > # 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 "!to=
 pdown || hint <=3D orig_hint" failed: file "../../../../uvm/uvm_map.c", lin=
 e 1795 map=3D0x8fe48d68 hint=3D0x7defb000 orig_hint=3D0x75172000 length=3D0=
 x1000 uobj=3D0x8fd5eaa0 uoffset=3D0 align=3D0 flags=3D0x101 entry=3D0x8dfc6=
 864 (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=3D0x...' address is in the panic message, and
 follow up on PR kern/51254 with the output?