Bug 162294

Summary:	Reading DMI memory parts using mmap freeze the system
Product:	Base System	Reporter:	Sylvain Galliano <sg>
Component:	kern	Assignee:	freebsd-bugs (Nobody) <bugs>
Status:	Open ---
Severity:	Affects Only Me
Priority:	Normal
Version:	8.2-RELEASE
Hardware:	Any
OS:	Any

Description Sylvain Galliano 2011-11-04 14:40:08 UTC

When several processes simultaneously read DMI datas (using dmidecode), the system freeze.

There is no issue in 8.1-RELEASE.

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)
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

Comment 1 Eitan Adler freebsd_committer

2017-12-31 08:01:43 UTC

For bugs matching the following criteria:

Status: In Progress Changed: (is less than) 2014-06-01

Reset to default assignee and clear in-progress tags.

Mail being skipped