NetBSD Problem Report #44061

From www@NetBSD.org  Sun Nov  7 18:48:47 2010
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Date: Sun,  7 Nov 2010 18:48:47 +0000 (UTC)
From: shattered@NetBSD.org
Reply-To: shattered@NetBSD.org
To: gnats-bugs@NetBSD.org
Subject: src/sys/gdbscripts/msgbuf doesn't work
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>Number:         44061
>Category:       bin
>Synopsis:       src/sys/gdbscripts/msgbuf doesn't work
>Confidential:   no
>Severity:       non-critical
>Priority:       medium
>Responsible:    bin-bug-people
>State:          open
>Class:          sw-bug
>Submitter-Id:   net
>Arrival-Date:   Sun Nov 07 18:50:00 +0000 2010
>Last-Modified:  Wed Oct 05 22:50:01 +0000 2016
>Originator:     Sergey Svishchev
>Release:        4.0_STABLE
>Organization:
>Environment:
# $NetBSD: msgbuf,v 1.5 2008/04/30 13:10:59 martin Exp $

>Description:
Typical output from 'msgbuf' command defined by this script:

msgbufp 0xcbbe1000: bufx 409 bufr 410 bufs 16368
Dumping 0xcbbe11a9 length 15959
Cannot access memory at address 0xcbbe5000


>How-To-Repeat:
Try to analyze a crash dump.
>Fix:
'x/s $p' instead of 'printf "%s\n", $p' works, but is not pretty.

>Audit-Trail:
From: David Holland <dholland-bugs@netbsd.org>
To: gnats-bugs@NetBSD.org
Cc: 
Subject: Re: bin/44061: src/sys/gdbscripts/msgbuf doesn't work
Date: Sun, 2 Oct 2016 19:04:22 +0000

 On Sun, Nov 07, 2010 at 06:50:00PM +0000, shattered@NetBSD.org wrote:
  > Typical output from 'msgbuf' command defined by this script:
  > 
  > msgbufp 0xcbbe1000: bufx 409 bufr 410 bufs 16368
  > Dumping 0xcbbe11a9 length 15959
  > Cannot access memory at address 0xcbbe5000
  > 
  > 
  > >How-To-Repeat:
  > Try to analyze a crash dump.
  > >Fix:
  > 'x/s $p' instead of 'printf "%s\n", $p' works, but is not pretty.

 ...why would this change whether $p is a valid pointer? Or is the
 issue that the "string" isn't terminated so it chugs off the end, and
 the behavior of x and printf in this case is different?

 -- 
 David A. Holland
 dholland@netbsd.org

From: Sergey Svishchev <shattered@NetBSD.org>
To: gnats-bugs@NetBSD.org
Cc: 
Subject: Re: bin/44061: src/sys/gdbscripts/msgbuf doesn't work
Date: Wed, 5 Oct 2016 23:38:18 +0300

 On Sun, Oct 02, 2016 at 07:05:00PM +0000, David Holland wrote:
 >The following reply was made to PR bin/44061; it has been noted by GNATS.
 >
 >From: David Holland <dholland-bugs@netbsd.org>
 >To: gnats-bugs@NetBSD.org
 >Cc:
 >Subject: Re: bin/44061: src/sys/gdbscripts/msgbuf doesn't work
 >Date: Sun, 2 Oct 2016 19:04:22 +0000
 >
 > On Sun, Nov 07, 2010 at 06:50:00PM +0000, shattered@NetBSD.org wrote:
 >  > Typical output from 'msgbuf' command defined by this script:
 >  >
 >  > msgbufp 0xcbbe1000: bufx 409 bufr 410 bufs 16368
 >  > Dumping 0xcbbe11a9 length 15959
 >  > Cannot access memory at address 0xcbbe5000
 >  >
 >  >
 >  > >How-To-Repeat:
 >  > Try to analyze a crash dump.
 >  > >Fix:
 >  > 'x/s $p' instead of 'printf "%s\n", $p' works, but is not pretty.
 >
 > ...why would this change whether $p is a valid pointer? Or is the
 > issue that the "string" isn't terminated so it chugs off the end, and
 > the behavior of x and printf in this case is different?

 IIRC, it was the latter -- unterminated string.  Haven't needed to run that script in a long while, though.

 -- 
 Sergey Svishchev

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