kern/162294: Reading DMI memory parts using mmap freeze the system

[Sylvain Galliano]

>Number:         162294
>Category:       kern
>Synopsis:       Reading DMI memory parts using mmap freeze the system
>Confidential:   no
>Severity:       serious
>Priority:       low
>Responsible:    freebsd-bugs
>State:          open
>Quarter:        
>Keywords:       
>Date-Required:
>Class:          sw-bug
>Submitter-Id:   current-users
>Arrival-Date:   Fri Nov 04 14:40:08 UTC 2011
>Closed-Date:
>Last-Modified:
>Originator:     Sylvain Galliano
>Release:        8.2-RELEASE
>Organization:
EfficientIP
>Environment:
FreeBSD solid.intranet 8.2-RELEASE-p3 FreeBSD 8.2-RELEASE-p3 #17: Thu Sep 29 19:28:07 UTC 2011     root at masterappliance-402.intranet:/usr/src/sys/i386/compile/SOLIDSERVER  i386
>Description:
When several processes simultaneously read DMI datas (using dmidecode), the system freeze.

There is no issue in 8.1-RELEASE.



>How-To-Repeat:
Execute the following script:

#!/bin/sh

/usr/local/sbin/dmidecode -s system-serial-number &
/usr/local/sbin/dmidecode -s system-serial-number &
/usr/local/sbin/dmidecode -s system-serial-number &
/usr/local/sbin/dmidecode -s system-serial-number &
. hundreds of lines


after few execution (sometime the first one), the system freeze

>Fix:
This issue seems to be related to mmap use in dmidecode.
In fact, if we change config.h in dmidecode port to disable mmap usage, all works fine. (In this case, dmidecode just open/read/close /dev/mem instead of mmap)


>Release-Note:
>Audit-Trail:
>Unformatted: