kern/74386: Killing watchdogd does not shutdown watchdog

[Alex Hoff]

>Number:         74386
>Category:       kern
>Synopsis:       Killing watchdogd does not shutdown watchdog
>Confidential:   no
>Severity:       serious
>Priority:       low
>Responsible:    freebsd-bugs
>State:          open
>Quarter:        
>Keywords:       
>Date-Required:
>Class:          sw-bug
>Submitter-Id:   current-users
>Arrival-Date:   Thu Nov 25 19:20:31 GMT 2004
>Closed-Date:
>Last-Modified:
>Originator:     Alex Hoff
>Release:        5.3 RELEASE
>Organization:
Sandvine Inc
>Environment:
FreeBSD 5.3 Release
>Description:
watchdogd when exiting will with remove the WD_ACTIVE flag by calling wd_ioctl with that bit set to 0. This is supposed to disable the watchdog, but since kern_clock.c:watchdog_config does not check to see if the ACTIVE flag is set, it will NEVER hit the "watchdog_enabled = 0;" code. Thus, when you kill watchdogd and stop kicking the watchdog, it will panic. 
>How-To-Repeat:
Load the software watchdog and kill watchdogd. The kernel should panic in ~15 seconds (depending on your timeout).
>Fix:
Patch:
Check to make sure the watchdog is actually active. Also remove duplicate WD_INTERVAL line.
--- kern_clock.c        2004-11-25 14:01:59.000000000 -0500
+++ kern_clock.old      2004-11-25 14:01:41.000000000 -0500
@@ -503,7 +503,8 @@
        u_int u;

        u = cmd & WD_INTERVAL;
+       if ((cmd & WD_ACTIVE) && u >= WD_TO_1SEC) {
-       if (cmd && u >= WD_TO_1SEC) {
-               u = cmd & WD_INTERVAL;
                watchdog_ticks = (1 << (u - WD_TO_1SEC)) * hz;
                watchdog_enabled = 1;
                *err = 0;
>Release-Note:
>Audit-Trail:
>Unformatted: