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Date:      Sun, 28 Jan 2001 13:12:46 -0800 (PST)
From:      tony@nua.ie
To:        freebsd-gnats-submit@FreeBSD.org
Subject:   bin/24704: syslog produces repeated corrupt messages to /dev/console under certain circumstances
Message-ID:  <200101282112.f0SLCk733189@freefall.freebsd.org>

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>Number:         24704
>Category:       bin
>Synopsis:       syslog produces repeated corrupt messages to /dev/console under certain circumstances
>Confidential:   no
>Severity:       serious
>Priority:       medium
>Responsible:    freebsd-bugs
>State:          open
>Quarter:        
>Keywords:       
>Date-Required:
>Class:          sw-bug
>Submitter-Id:   current-users
>Arrival-Date:   Sun Jan 28 13:20:01 PST 2001
>Closed-Date:
>Last-Modified:
>Originator:     Tony Byrne
>Release:        4.2-STABLE
>Organization:
Nua Ltd.
>Environment:
FreeBSD cerberus.merrion.nua.net 4.2-STABLE FreeBSD 4.2-STABLE #0: Wed Jan 24 15:45:09 GMT 2001     tony@cerberus.merrion.nua.net:/usr/obj/usr/src/sys/CERBERUS  i386
>Description:
Under certain circumstances, syslogd will quickly and repeatedly fill /dev/console with corrupt log output.  Messages are output at a rate of tens per second.  Whenever syslogd exhibits this behaviour, it consumes a large slice of CPU time.  An example of this output is:

4 23:17:23 cerberus /kernel: Jan 24 23:17:23 cerberus /kernel: Jan 24 23:17:23 cerberus /kernel: Jan 24 23:17:23 cerberus /kernel: Jan 24 23:17:23 cerberus /kernel: Jan 24 23:17:23 cerberus /kernel: Jan 24 23:17:23 cerberus /kernel: Jan 24 23:17:23 cerberus /kernel: Jan 24 23:17:23 cerberus /kernel: Jan 24 23:17:23 cerberus /kernel: Jan 24 23:17:23 cerberus /kernel: Jan 24 23:17:23 cerberus /kernel: Jan 24 23:17:23 cerberus syslogd: restart

These messsages appear on the console without line breaks and without any meaningful log content.

The problem seems to be connected with the newly added LOG_CONSOLE facility (MFC'd recently from CURRENT).  It occurs whenever /etc/syslog.conf contains an entry that causes log messages with the LOG_CONSOLE facility to be directed to /dev/console.  A typical example of a triggering syslog.conf entry would be:

*.*                 /dev/console


>How-To-Repeat:
1) Edit /etc/syslog.conf

2) Insert the line:
   *.*                /dev/console
   near the top of the file.

3) Restart syslogd
>Fix:
Ensure that syslog.conf does not use wildcards in such a way that messages with the LOG_CONSOLE facility are directed to /dev/console.

The syslogd.c source file seems to include code to prevent this particular problem from arising, but it appears to be broken.

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


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