From thomas@smtp.nordcom.net  Sun Sep  7 11:53:15 2003
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Message-Id: <20030907203347.U2378@lullog.lemur.nord.de>
Date: Sun, 7 Sep 2003 20:37:57 +0200 (CEST)
From: Thomas Wintergerst <thomas@smtp.nordcom.net>
Reply-To: Thomas.Wintergerst@nord-com.net
To: FreeBSD-gnats-submit@freebsd.org
Subject: Possible kernel panic while loading kernel module

>Number:         56570
>Category:       kern
>Synopsis:       Possible kernel panic while loading kernel module
>Confidential:   no
>Severity:       serious
>Priority:       low
>Responsible:    freebsd-bugs
>State:          closed
>Quarter:        
>Keywords:       
>Date-Required:  
>Class:          sw-bug
>Submitter-Id:   current-users
>Arrival-Date:   Sun Sep 07 12:00:29 PDT 2003
>Closed-Date:    Tue Sep 23 07:46:13 PDT 2003
>Last-Modified:  Tue Sep 23 07:46:13 PDT 2003
>Originator:     Thomas Wintergerst
>Release:        FreeBSD 5.1-RELEASE i386
>Organization:
none
>Environment:
System: FreeBSD lullog.lemur.nord.de 5.1-RELEASE FreeBSD 5.1-RELEASE #3: Mon Jul 28 20:18:13 CEST 2003 operator@lullog.lemur.nord.de:/usr/src/sys/i386/compile/LULLOG i386

	As shown above FreeBSD 5.1-RELEASE, i386 platform.

>Description:

	Assume kernel module "othmod" depends on "basemod". "basemod" declares
	version number 2. "othmod" declares to depend on "basemod" between 1 and
	3, 1 is preferred. The attempt to load "othmod" after "basemod" will
	cause a kernel panic.

	If "othmod" declared to depend only on "basemod" version 2 (exact
	match), this would be not problem.

>How-To-Repeat:

	Just create a kernel module that depends on another. The dependency
	declaration must contain a preferred version other than the existing
	one, but the minimum and maximum version must contain the available
	version.

>Fix:

	Just apply the following patch to "/usr/src/sys/kern/kern_linker.c":

*** kern_linker.c.org	Mon Mar  3 23:53:35 2003
--- kern_linker.c	Mon Jul 28 20:16:57 2003
***************
*** 1085,1091 ****
  			return (mod);
  		if (ver >= verinfo->md_ver_minimum &&
  		    ver <= verinfo->md_ver_maximum &&
! 		    ver > bestmod->version)
  			bestmod = mod;
  	}
  	return (bestmod);
--- 1085,1091 ----
  			return (mod);
  		if (ver >= verinfo->md_ver_minimum &&
  		    ver <= verinfo->md_ver_maximum &&
! 		    (bestmod == NULL || ver > bestmod->version))
  			bestmod = mod;
  	}
  	return (bestmod);

>Release-Note:
>Audit-Trail:
State-Changed-From-To: open->closed 
State-Changed-By: fjoe 
State-Changed-When: Tue Sep 23 07:45:52 PDT 2003 
State-Changed-Why:  
Thanks, committed! 

http://www.freebsd.org/cgi/query-pr.cgi?pr=56570 
>Unformatted:
