NetBSD Problem Report #55467
From www@netbsd.org Tue Jul 7 01:16:29 2020
Return-Path: <www@netbsd.org>
Received: from mail.netbsd.org (mail.netbsd.org [199.233.217.200])
(using TLSv1.2 with cipher ECDHE-RSA-AES256-GCM-SHA384 (256/256 bits))
(Client CN "mail.NetBSD.org", Issuer "mail.NetBSD.org CA" (not verified))
by mollari.NetBSD.org (Postfix) with ESMTPS id 999351A9213
for <gnats-bugs@gnats.NetBSD.org>; Tue, 7 Jul 2020 01:16:29 +0000 (UTC)
Message-Id: <20200707011628.6A8D01A921A@mollari.NetBSD.org>
Date: Tue, 7 Jul 2020 01:16:28 +0000 (UTC)
From: rokuyama.rk@gmail.com
Reply-To: rokuyama.rk@gmail.com
To: gnats-bugs@NetBSD.org
Subject: tmpfs calls pmap_kenter_pa(9) with virtual address with page offset
X-Send-Pr-Version: www-1.0
>Number: 55467
>Category: kern
>Synopsis: tmpfs calls pmap_kenter_pa(9) with virtual address with page offset
>Confidential: no
>Severity: serious
>Priority: medium
>Responsible: kern-bug-people
>State: closed
>Class: sw-bug
>Submitter-Id: net
>Arrival-Date: Tue Jul 07 01:20:00 +0000 2020
>Closed-Date: Sun Sep 19 04:41:48 +0000 2021
>Last-Modified: Sun Sep 19 04:41:48 +0000 2021
>Originator: Rin Okuyama
>Release: 9.99.69
>Organization:
Department of Physics, Meiji University
>Environment:
NetBSD rb800 9.99.69 NetBSD 9.99.69 (RB800-$Revision: 1.37 $) #13: Tue Jul 7 10:00:31 JST 2020 rin@latipes:/usr/src/sys/arch/evbppc/compile/RB800 evbppc
>Description:
By recent changes, tmpfs became to call pmap_kenter_pa(9) with ``va''
argument with page offset via ubc_uiomove(9).
For many ports, page offset of ``va'' is silently truncated, but this
causes KASSERT failure for powerpc/booke:
----
/etc/rc.conf is not configured. Multiuser boot aborted.
Enter pathname of shell or RETURN for /bin/sh:
We recommend that you create a non-root account and use su(1) for root access.
rb800# mount /tmp
rb800# dd if=/dev/zero of=/tmp/zero bs=1k count=1024
panic: kernel diagnostic assertion "trunc_page(tlb.tlb_va) == tlb.tlb_va" failed: file "../../../../arch/powerpc/booke/e500_tlb.c", line 233
cpu0: Begin traceback...
0x00bfbb60: at vpanic+0x12c
0x00bfbb90: at kern_assert+0x60
0x00bfbbd0: at tlb_to_hwtlb+0x174
0x00bfbc10: at e500_tlb_update_addr+0x50
0x00bfbc60: at pmap_tlb_update_addr+0x8c
0x00bfbc90: at pmap_kenter_pa+0xf0
0x00bfbcc0: at ubc_alloc.constprop.1+0x30c
0x00bfbd40: at ubc_uiomove+0x118
0x00bfbdb0: at tmpfs_write+0x210
0x00bfbdf0: at VOP_WRITE+0x3c
0x00bfbe20: at vn_write+0x14c
0x00bfbe50: at dofilewrite+0x8c
0x00bfbeb0: at syscall+0x2cc
0x00bfbf20: user SC trap #4 by 0xefc50d48: srr1=0x2d230
r1=0xffff7950 cr=0x24224882 xer=0 ctr=0xefc50d40
cpu0: End traceback...
Stopped in pid 112.112 (dd) at netbsd:cpu_Debugger+0xc: tw 0, r1, r
1
----
>How-To-Repeat:
Described above.
>Fix:
Not known.
I will bisect which commit caused this if required.
According to my record, kernel as of mid April worked fine.
>Release-Note:
>Audit-Trail:
From: "Rin Okuyama" <rin@netbsd.org>
To: gnats-bugs@gnats.NetBSD.org
Cc:
Subject: PR/55467 CVS commit: src/sys/uvm
Date: Thu, 9 Jul 2020 09:24:33 +0000
Module Name: src
Committed By: rin
Date: Thu Jul 9 09:24:33 UTC 2020
Modified Files:
src/sys/uvm: uvm_bio.c
Log Message:
PR kern/55467
tmpfs calls pmap_kenter_pa(9) with virtual address with page offset
Bisectioning revealed that the failure starts with this commit:
sys/fs/tmpfs/tmpfs_vnops.c rev 1.142:
http://cvsweb.netbsd.org/bsdweb.cgi/src/sys/fs/tmpfs/tmpfs_vnops.c#rev1.142
by which tmpfs became to use UBC_FAULTBUSY flag for ubc_uiomove(9).
If this flag is specified, pmap_kenter_pa(9) is called with virtual
address with page offset via ubc_alloc(9):
https://nxr.netbsd.org/xref/src/sys/uvm/uvm_bio.c#616
Most ports seem to neglect silently page offset of va argument for
pmap_kenter_pa(9). However, it causes KASSERT failure correctly for
powerpc/booke. So, truncate page offset there.
Now, tmpfs works just fine on evbppc-booke, and I've confirmed that
no new failures are detected by ATF.
Discussed with chs@. Thanks!
To generate a diff of this commit:
cvs rdiff -u -r1.120 -r1.121 src/sys/uvm/uvm_bio.c
Please note that diffs are not public domain; they are subject to the
copyright notices on the relevant files.
State-Changed-From-To: open->closed
State-Changed-By: rin@NetBSD.org
State-Changed-When: Sun, 19 Sep 2021 04:41:48 +0000
State-Changed-Why:
Fixed. No release branches should be affected.
>Unformatted:
(Contact us)
$NetBSD: query-full-pr,v 1.46 2020/01/03 16:35:01 leot Exp $
$NetBSD: gnats_config.sh,v 1.9 2014/08/02 14:16:04 spz Exp $
Copyright © 1994-2020
The NetBSD Foundation, Inc. ALL RIGHTS RESERVED.