Subject: kern/14792: 'cat /dev/bktr' causes kernel fault & system halt
To: None <>
From: None <>
List: netbsd-bugs
Date: 11/30/2001 04:02:07
>Number:         14792
>Category:       kern
>Synopsis:       'cat /dev/bktr' causes kernel fault & system halt
>Confidential:   no
>Severity:       critical
>Priority:       medium
>Responsible:    kern-bug-people
>State:          open
>Class:          sw-bug
>Submitter-Id:   net
>Arrival-Date:   Fri Nov 30 04:03:00 PST 2001
>Originator:     Mike Blomgren
>Release:        1.5.1 & 1.5.2
NetBSD mbbsd 1.5.2 NetBSD 1.5.2 (GENERIC) #3: Sat Aug 18 23:37:05 CEST 
2001 i386

When doing a 'cat /dev/bktr', the kernel complains on a page feult, and halts all operations on the machine. A db> prompt is displayed. The only option (to my knowledge) is to reboot the machine. The error mesage displayed is (may vary slightly between machines we tested it on):

uvm_fault(0xc4674814, 0x0, 0, 1) -> 1
kernel: page fault trap, code=0
Stopped in cat at       bktropen+0x18:   movl       0(%eax,%edx,4),%edx

We discovered the problem accidentally when doing a recursive grep for a string in files on all filesystems. We nover got passed the /dev directory. Apparently the problem occurs when a process wants to open the device.

The /dev/bktr apparently has something to do with a BrookTree video device. Somthing that has not been installed in any of the machines we could reproduce the problem on. All machines were 'vanilla' PC's: AMD or Intel processor, with no extraordinary peripherals. NIC, keyboard, mouse, IDE harddisk. Soundcard in one of them.

Install NetBSD 1.5.1 or 1.5.2
Login as root, or any other user
'cat /dev/bktr'
If I knew how, I'd uninstall the /dev/bktr device & drivers...