NetBSD Problem Report #42376
From Wolfgang.Stukenbrock@nagler-company.com Wed Nov 25 12:44:40 2009
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Date: Wed, 25 Nov 2009 13:44:37 +0100 (CET)
From: Wolfgang.Stukenbrock@nagler-company.com
Reply-To: Wolfgang.Stukenbrock@nagler-company.com
To: gnats-bugs@gnats.NetBSD.org
Subject: ahd-driver bug in cmd-queuing - duplicate TAG send to device
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>Number: 42376
>Category: kern
>Synopsis: ahd-driver bug in cmd-queuing - duplicate TAG send to device
>Confidential: no
>Severity: serious
>Priority: high
>Responsible: kern-bug-people
>State: open
>Class: sw-bug
>Submitter-Id: net
>Arrival-Date: Wed Nov 25 12:45:00 +0000 2009
>Originator: W. Stukenbrock
>Release: NetBSD 4.0
>Organization:
Dr. Nagler & Company GmbH
>Environment:
System: NetBSD test-s0 4.0 NetBSD 4.0 (NSW-WS) #2: Fri Nov 6 11:14:49 CET 2009 wgstuken@s012:/export/NetBSD-4.0/N+C-build/.OBJDIR_amd64/export/NetBSD-4.0/src/sys/arch/amd64/compile/NSW-WS amd64
Architecture: x86_64
Machine: amd64
>Description:
The ADH driver manages 512 SBC entries, but there are only 256 different
cmd-TAGs possbile on the SCSI-bus.
So there is a SCB-manaagment implemented, that avoid the use of a
conflicting SCB-tag on a device.
Accedently the check, if a conflict may happen or not is broken.
Command queuing is enabled on the scspi-layer, if xs_tag_type is
set to the correct SCSI-message value.
Now in aic79xx_osm.c this value is checked for non-zero to be
non-cnflicting in any case. It should be checked for zero instead.
>How-To-Repeat:
This is not easy ...
I've the problem, that on some disks on heavy load some commands are
rejected by some oth the disk drives with ASC=4d (Deivce reports conflicting TAG).
After that a device timeout happens with the SCB with the same TAG
pattern in the lower 8 bits as reported .
I've found no way to reproduce it on demand up to now.
I've analysed the code to find the reason for it - see patch and
description above..
>Fix:
The following patch to /usr/src/sys/ic/aic79xx_osm.c will fix the
problem:
--- aic79xx_osm.c 2008/09/26 11:20:25 1.2
+++ aic79xx_osm.c 2009/11/25 10:12:40
@@ -312,7 +312,7 @@
tinfo = ahd_fetch_transinfo(ahd, channel, our_id,
target_id, &tstate);
- if (xs->xs_tag_type != 0 ||
+ if (xs->xs_tag_type == 0 ||
(tinfo->curr.ppr_options & MSG_EXT_PPR_IU_REQ) != 0)
col_idx = AHD_NEVER_COL_IDX;
else
>Unformatted:
(Contact us)
$NetBSD: query-full-pr,v 1.39 2013/11/01 18:47:49 spz Exp $
$NetBSD: gnats_config.sh,v 1.8 2006/05/07 09:23:38 tsutsui Exp $
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