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From: jmorris@imagine.matrox.com (Jacques Morris)
Newsgroups: comp.os.os2.programmer
Subject: OS/2 Device Drivers
Summary: Double exception bug
Message-ID: <1991Jun11.210803.9521@pandora.matrox.com>
Date: 11 Jun 91 21:08:03 GMT
Sender: news@pandora.matrox.com (Usenet Administration)
Organization: Matrox Ltd.
Lines: 52


   I'm writing an interrupt-driven device driver for OS/2 and
   have been stumped by a bug for a while.

   I'm running OS/2 on a ALR 80386 EISA machine and I've reserved
   interrupt level 7 for my device.

   I'm using the Microsoft DDK with the debugger kernel os2krnl.170.
   After installing this driver at boot time (without errors) I
   issue a DosDevIOCtl() call with the device function parameter set
   to 0x80. At this point the CPU (80386) generates an exception and
   the debugger issues the message

Trap 8 - Double Exception Detected 0000
AX=0067  BX=E000  CX=03FF  DX=0131  SP=007C  BP=626F  SI=014C  DI=0000
IP=36C9  CS=0230  DS=0B58  ES=01A8  SS=1970  -- NV UP DI NG NZ NA PO CY
GDTR=110020 1B5F  IDTR=11336E 03FF  TR=0010  LDTR=0028 IOPL=1 MSW=PM EM TS
0230:36C9 1E                 PUSH    DS

   ...processing then continues until a second exception occurs...

Trap 12 (0CH) - Stack Segment Overrun or Not Present 0000
AX=3848  BX=E024  CX=FFFE  DX=002C  SP=004E  BP=0076  SI=1604 DI=002D
IP=002B  CS=01F0  DS=01F8  ES=01F8  SS=1970  -- NV UP DI NG NZ NA PO CY
GDTR=110020 1B5F  IDTR=11336E 03FF  TR=0010  LDTR=0028 IOPL=3 MSW=PM EM TS
01F0:002B 36F6063EFF01       TEST    BYTE PTR SS:[FF3E],01     SS:FF3E=INVALID

   Continuing the processing at this point hangs the system and the
   kernel issues the following message before dying:

            The system detected an internal processing
            error at location # 0230:0008


   Now these exceptions seem to occur in the kernel so debugging is 
   difficult to say the least. If anyone has any ideas please let me know
   by E-Mail. I would greatly appreciate it!


                                                        Thanks.

 ______________________________________________________________________

   Jacques Morris               E-Mail : jmorris@matrox.com
   Software engineer            Voice  : (514) 685-7230 ext. 2319
   Matrox Electronics Systems   Fax    : (514) 685-2853
   Montreal, Canada             Date   : June 11th, 1991
 ______________________________________________________________________

                The opinions expressed are not mine.
                I found them somewhere, I swear.
 ______________________________________________________________________