Subject: port-alpha/29556: pmap_emulate_reference: write but not FOW
To: None <,,>
From: None <>
List: netbsd-bugs
Date: 02/28/2005 07:22:01
>Number:         29556
>Category:       port-alpha
>Synopsis:       pmap_emulate_reference: write but not FOW
>Confidential:   no
>Severity:       serious
>Priority:       medium
>Responsible:    port-alpha-maintainer
>State:          open
>Class:          sw-bug
>Submitter-Id:   net
>Arrival-Date:   Mon Feb 28 07:22:01 +0000 2005
>Originator:     YAMAMOTO Takashi <>
>Release:        NetBSD 2.99.14

System: NetBSD kaeru 2.99.14
Architecture: alpha
Machine: alpha
	i occasionally see the following panics on my box.

	before i enabled the debug check (pmap.c rev.1.208),
	it used to be infinite traps, which can be recovered by
	"ALPHA_TBIA(); alpha_pal_imb();" equivalent from ddb.
	so i guess it's due to stale tlbs or something like that.

	panic: pmap_emulate_reference: write but not FOW
	Stopped in pid 7723.1 (cc1plus) at      netbsd:cpu_Debugger+0x4:        ret     zero,(ra)
	db> bt
	cpu_Debugger() at netbsd:cpu_Debugger+0x4
	panic() at netbsd:panic+0x1f8
	pmap_emulate_reference() at netbsd:pmap_emulate_reference+0x18c
	trap() at netbsd:trap+0x58c
	XentMM() at netbsd:XentMM+0x20
	--- memory management fault (from ipl 0) ---
	--- user mode ---