Date: Wed, 18 Oct 2006 22:00:49 +0200 From: Ulrich Spoerlein <uspoerlein@gmail.com> To: FreeBSD-gnats-submit@FreeBSD.org Cc: freebsd-rc@FreeBSD.org Subject: conf/104549: rc.d/nfsd needs special _find_processes function Message-ID: <20061018200049.GA69724@coyote.q.local> Resent-Message-ID: <200610182010.k9IKAI9t045118@freefall.freebsd.org>
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>Number: 104549
>Category: conf
>Synopsis: rc.d/nfsd needs special _find_processes function
>Confidential: no
>Severity: non-critical
>Priority: low
>Responsible: freebsd-bugs
>State: open
>Quarter:
>Keywords:
>Date-Required:
>Class: sw-bug
>Submitter-Id: current-users
>Arrival-Date: Wed Oct 18 20:10:17 GMT 2006
>Closed-Date:
>Last-Modified:
>Originator: Ulrich Spoerlein
>Release: FreeBSD 6.2-PRERELEASE i386
>Organization:
>Environment:
>Description:
When running multiple nfsd processes, there is one master process and several slave processes.
As soon as the master process receives a SIGUSR1 all nfsd will terminate. This results in a
race condition when shutting down nfsd. The kill signal is not send to a list of PIDs, but
a list of PIDs is iterated and kill(1) called for every PID.
As soon as the kill-loop hits the master nfsd, all subsequent kills will go to stale PIDs
eventually killing of other innocent processes.
>How-To-Repeat:
Crank up the number of processes to make it more obvious:
nfs_server_enable="YES"
nfs_server_flags="-u -t -n 64"
run /etc/rc.d/nfsd start and /etc/rc.d/nfsd stop. You will most probably see several errors
from kill. Check $?
>Fix:
This is only a proof of concept as I'm not sure if this should be kludged into rc.subr or
if we should provide a minimal override in rc.d/nfsd.
You might wanna diff the two functions to see what I did. (Change _fp_args, extend the if test
to if-master-and-same-jailid).
--- nfsd.diff begins here ---
--- nfsd 2006-10-18 11:15:50.000000000 +0200
+++ nfsd.new 2006-10-18 11:15:47.000000000 +0200
@@ -44,4 +44,42 @@
return 0
}
+# Overwrite the _find_processes() function. We are only interested in the
+# nfsd master process. Only this one should get the kill signal.
+
+_find_processes()
+{
+ if [ $# -ne 3 ]; then
+ err 3 'USAGE: _find_processes procname interpreter psargs'
+ fi
+ _procname=$1
+ _interpreter=$2
+ _psargs=$3
+
+ _pref=
+ _procnamebn=${_procname##*/}
+ _fp_args='_arg0 _argv _x'
+ _fp_match='case "$_arg0" in
+ $_procname|$_procnamebn|${_procnamebn}:|"(${_procnamebn})"|"[${_procnamebn}]")'
+
+ _proccheck='
+ ps 2>/dev/null -o "pid,jid,command" '"$_psargs"' |
+ while read _npid _jid '"$_fp_args"'; do
+ case "$_npid" in
+ PID)
+ continue;;
+ esac; '"$_fp_match"'
+ if [ "$_argv" = "master" -a "$JID" -eq "$_jid" ];
+ then echo -n "$_pref$_npid";
+ _pref=" ";
+ fi
+ ;;
+ esac
+ done'
+
+# debug "in _find_processes: proccheck is ($_proccheck)."
+ eval $_proccheck
+}
+
+
run_rc_command "$1"
--- nfsd.diff ends here ---
--h31gzZEtNLTqOjlF
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--- nfsd 2006-10-18 11:15:50.000000000 +0200
+++ nfsd.new 2006-10-18 11:15:47.000000000 +0200
@@ -44,4 +44,42 @@
return 0
}
+# Overwrite the _find_processes() function. We are only interested in the
+# nfsd master process. Only this one should get the kill signal.
+
+_find_processes()
+{
+ if [ $# -ne 3 ]; then
+ err 3 'USAGE: _find_processes procname interpreter psargs'
+ fi
+ _procname=$1
+ _interpreter=$2
+ _psargs=$3
+
+ _pref=
+ _procnamebn=${_procname##*/}
+ _fp_args='_arg0 _argv _x'
+ _fp_match='case "$_arg0" in
+ $_procname|$_procnamebn|${_procnamebn}:|"(${_procnamebn})"|"[${_procnamebn}]")'
+
+ _proccheck='
+ ps 2>/dev/null -o "pid,jid,command" '"$_psargs"' |
+ while read _npid _jid '"$_fp_args"'; do
+ case "$_npid" in
+ PID)
+ continue;;
+ esac; '"$_fp_match"'
+ if [ "$_argv" = "master" -a "$JID" -eq "$_jid" ];
+ then echo -n "$_pref$_npid";
+ _pref=" ";
+ fi
+ ;;
+ esac
+ done'
+
+# debug "in _find_processes: proccheck is ($_proccheck)."
+ eval $_proccheck
+}
+
+
run_rc_command "$1"
--h31gzZEtNLTqOjlF--
>Release-Note:
>Audit-Trail:
>Unformatted:
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