From: andy@homebase.vistachrome.com (Andy Finkenstadt)
Subject: Re: Turning on cache causes random kernel panics, core dumps
Reply-To: andy@homebase.vistachrome.com
Organization: Vista-Chrome Incorporated
Date: Wed, 9 Sep 1992 16:06:24 GMT

The cache chips are not fast enough for the mother board.  They are
causing spurious "cache hits" on memory that isn't cached.  This can
also be caused by a defective motherboard and noise.  Insufficient
power supplied to everything can also be a factor.  (I had a 486-50
sitting with 4 1.3gig drives tape floppies ethernet multiport board
with only a 250watt power supply and upgrading to a 400W supply
solved a LOT of mysterious problems.)

-Andy

root@candle.uucp (Bruce Momjian) writes:

>I am running SCO Unix SVr3.2 2.0 on an Everex Next 386/33.  The box is
>stuffed to the gills, with 2 SCSI hard drives, 2 SCSI tape drives, an
>Arcnet multiport card, an ethernet card running TCP/IP, and two floppy
>drives.

>With the motherboard cache is turned off, it runs fine.  When the cache
>is turned on, the system dumps core of executables at random, and
>finally kernel panics.  Attached are tracebacks of three of those
>panics.  I notice that the panics seem to all occur in ttxput().  I
>tried removing the Arcnet and ethernet cards, but the problem did not go
>away.  

>The first panic occured when the system successfully went into
>multi-user mode, and I was in an application.  The second was
>caused by my typing 'ps -ef' at the console.  The third was caused by the
>TCP/IP starting up before generating logins.  In all cases, I was the
>only one using the system, and all occurred within 10 minutes of boot. 
>I still have the panic images.

>The core dumps seem to occur most often in the tty database startup
>section before logins are started, and can also report 'no space', even
>though there is tons of space on all drives.  Core dumps can also happen
>in applications.

>Many thanks to those who responded to my 'modem hanging system' query. 
>I will be able to prevent the hangs now.  Thanks for reading and perhaps
>responding to this lengthy posting.

>--------------------------------------------------------------------------
>			PANIC WHEN STARTING APPLICATION

>$ crash brs_dump
>dumpfile = brs_dump, namelist = /unix, outfile = stdout
>> t
>STACK TRACE FOR PROCESS 19:
>STKADDR   FRAMEPTR  FUNCTION  POSSIBLE ARGUMENTS
>e0000c24  e0000c3c  prf_task (e,d008c629,d00b0790,160)
>e0000c44  e0000c68  cmn_err  (3,d00b1058,e,d00a2e7c)
>e0000c70  e0000c94  k_trap   (e0000ca0)
>Trap e    e0000ca0  cmntrap  from d009b6d0 in ttxput  
>  ax:      1b cx:      40 dx: 1893b7b bx:    1805 fl:    10246 ds: 160 fs:   0
>  sp:e0000cd0 bp:e0000d14 si:d00a2e7c di:      1b err:d0100000 es: 160 gs:   0
>e0000ca8  e0000d14  ttxput   (d00a2e7c,d10dddd0,3f,d00a2e7c)
>e0000d1c  e0000d44  ttwrite  (d00a2e7c,d0100000,4b)
>e0000d4c  e0000d58  vidwrite (d00cc708,d010f074,d00c8348,0)
>e0000d60  e0000d74  cnwrite  (0,2,d00c8348,d010f074)
>e0000d7c  e0000db4  s5writei (d010f074,e0000e38,d00b0b30,52)
>e0000dbc  e0000dec  rdwr     (2)
>e0000df4  e0000df8  write    (188f92c,1893b3c,52,d0117868)
>e0000e00  e0000e2c  systrap  (e0000e38)
>          e0000e38  sys_call from 00079274
>  ax:       4 cx:       0 dx: 189abe8 bx:      52 fl:      202 ds:  1f fs:   0
>  sp:e0000e68 bp:7ffffce8 si: 188f92c di: 1893b3c err:       4 es:  1f gs:   0
>> quit

>----------------------------------------------------------------------

>	PANIC WHEN DOING ps -ef

>/u/kernel_dump> crash ps-ef_dump
>dumpfile = ps-ef_dump, namelist = /unix, outfile = stdout
>> t
>STACK TRACE FOR PROCESS 5:
>STKADDR   FRAMEPTR  FUNCTION  POSSIBLE ARGUMENTS
>e0000c14  e0000c2c  prf_task (6,d008c629,d00b0790,160)
>e0000c34  e0000c58  cmn_err  (3,d00b1058,6,d00a2e7c)
>e0000c60  e0000c84  k_trap   (e0000c90)
>Trap 6    e0000c90  cmntrap  from d009b6da in ttxput  
>  ax:      65 cx:      37 dx:  40eebe bx:    1805 fl:    10213 ds: 160 fs:   0
>  sp:e0000cc0 bp:e0000d04 si:d00a2e7c di:      65 err:       0 es: 160 gs:   0
>e0000c98  e0000d04  ttxput   (d00a2e7c,d10de0a0,36,d00a2e7c)
>e0000d0c  e0000d34  ttwrite  (d00a2e7c,0,8228)
>e0000d3c  e0000d48  vidwrite (d00cc708,0,d00c8030,96b0)
>e0000d50  e0000d64  cnwrite  (0,d011325c)
>e0000d6c  e0000d74  sywrite  (301,2,d00c8030,d011325c)
>e0000d7c  e0000db4  s5writei (d011325c,e0000e38,d00b0b30,37)
>e0000dbc  e0000dec  rdwr     (2)
>e0000df4  e0000df8  write    (40d3d0,40ee88,37,d0117868)
>e0000e00  e0000e2c  systrap  (e0000e38)
>          e0000e38  sys_call from a00037a4
>  ax:       4 cx:       0 dx:       2 bx:      37 fl:      202 ds:  1f fs:   0
>  sp:e0000e68 bp:7ffffaa4 si:  40d3d0 di:  40ee88 err:       4 es:  1f gs:   0
>> quit

>--------------------------------------------------------------------

>		PANIC WHEN TCP/IP STARTING UP

>dumpfile = tcp_dump, namelist = /unix, outfile = stdout
>t
>> STACK TRACE FOR PROCESS 10:
>STKADDR   FRAMEPTR  FUNCTION  POSSIBLE ARGUMENTS
>e0000c14  e0000c2c  prf_task (6,d008c629,d00b0790,160)
>e0000c34  e0000c58  cmn_err  (3,d00b1058,6,d00a2e7c)
>e0000c60  e0000c84  k_trap   (e0000c90)
>Trap 6    e0000c90  cmntrap  from d009b6da in ttxput  
>  ax:      66 cx:       0 dx:       0 bx:    1805 fl:    10213 ds: 160 fs:   0
>  sp:e0000cc0 bp:e0000d04 si:d00a2e7c di:      66 err:       0 es: 160 gs:   0
>e0000c98  e0000d04  ttxput   (d00a2e7c,66,0,d00a2e7c)
>e0000d0c  e0000d34  ttwrite  (d00a2e7c,0,dbc)
>e0000d3c  e0000d48  vidwrite (d00cc708,0,d00c8084,ec00)
>e0000d50  e0000d64  cnwrite  (0,d011325c)
>e0000d6c  e0000d74  sywrite  (301,2,d00c8084,d011325c)
>e0000d7c  e0000db4  s5writei (d011325c,e0000e38,d00b0b30,8)
>e0000dbc  e0000dec  rdwr     (2)
>e0000df4  e0000df8  write    (4006e0,4013a0,8,4005a8)
>e0000e00  e0000e2c  systrap  (e0000e38)
>          e0000e38  sys_call from a00037a4
>  ax:       4 cx:       0 dx:       0 bx:       8 fl:      202 ds:  1f fs:   0
>  sp:e0000e68 bp:7ffffa7c si:  4006e0 di:  4013a0 err:       4 es:  1f gs:   0
>> quit

>-- 
>Bruce Momjian                      |  830 Blythe Avenue
>root%candle.uucp@bts.com           |  Drexel Hill, Pennsylvania 19026 
>                                   |  (215) 353-9879(w)  853-3000(h)
-- 
Andrew Finkenstadt       | Vista-Chrome, Inc.   |           andy@GEnie
GEnie Unix Sysop/Manager | The Printing House   |    NIC Handle: AF136
+1 904 222 2639 home     | 1600 Capital Cir SW  |   ...!uunet!rde!andy
+1 904 575 0189 work     | Tallahassee FL 32310 | andy@vistachrome.com

     The game of love is never called off on account of darkness.
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