Subject: kern/10761: pmap_unwire panic during shutdown with LOCKDEBUG enabled
To: None <gnats-bugs@gnats.netbsd.org>
From: Simon Burge <simonb@wasabisystems.com>
List: netbsd-bugs
Date: 08/04/2000 21:45:14
>Number:         10761
>Category:       kern
>Synopsis:       pmap_unwire panic during shutdown with LOCKDEBUG enabled
>Confidential:   no
>Severity:       serious
>Priority:       high
>Responsible:    kern-bug-people
>State:          open
>Class:          sw-bug
>Submitter-Id:   net
>Arrival-Date:   Fri Aug 04 21:46:00 PDT 2000
>Closed-Date:
>Last-Modified:
>Originator:     Simon Burge
>Release:        NetBSD-current 20000805 sources
>Organization:
Wasabi Systems
>Environment:
	System: NetBSD wincen 1.5D NetBSD 1.5D (WINCEN) #325: Sat Aug 5 14:30:22 EST 2000
	simonb@wincen:/usr/obj/sys/arch/i386/compile/WINCEN i386

>Description:
	With a -current kernel w/ LOCKDEBUG enabled, I get the following
	on each shutdown:

	panic: pmap_unwire: invalid (unmapped) va
	Stopped in ntpd at      cpu_Debugger+0x4:       leave
	db> trace
	cpu_Debugger(c995f110,804a000,c995f110,c9bcfe58,c01fea6b) at cpu_Debugger+0x4
	panic(c02535c0,c996bbc0,804a000,c9bcfe90,c01e7600) at panic+0x64
	pmap_unwire(c995f110,804a000) at pmap_unwire+0x7b
	uvm_fault_unwire_locked(c995e2e0,8048000,807e000) at uvm_fault_unwire_locked+0xf0 
	uvm_unmap_remove(c995e2e0,0,bfbfe000,c9bcfee0,c995e2e0) at uvm_unmap_remove+0xd9
	uvm_unmap(c995e2e0,0,bfbfe000,c995e2e0,c9bcff28) at uvm_unmap+0x85
	uvm_deallocate(c995e2e0,0,bfbfe000) at uvm_deallocate+0x38
	exit1(c9b947d4,0,c9bcffa8,c01fff8b,c9b947d4) at exit1+0x13f
	sys_exit(c9b947d4,c9bcff88,c9bcff80,0,ffffffff) at sys_exit+0x14
	syscall() at syscall+0x21b
	--- syscall (number 1) ---
	0x48126cab:
	db> 

>How-To-Repeat:
	Add LOCKDEBUG to kernel config, run ntpd and shutdown.  This didn't
	appear to happen on LOCKDEBUG kernels - I'll double check this.

	Note that killing ntpd doesn't cause the panic - it only happens
	on shutdown.
>Fix:
>Release-Note:
>Audit-Trail:
>Unformatted: