svn commit: r304244 - head/sys/kern

[Gleb Smirnoff]

Author: glebius
Date: Tue Aug 16 21:55:34 2016
New Revision: 304244
URL: https://svnweb.freebsd.org/changeset/base/304244

Log:
  We should not be allowing a timeout to reset when a drain is in progress on
  it (either async or sync drain).
  
  At this moment the only user of drain is TCP, but TCP wouldn't reschedule a
  callout after it has drained it, since it drains only when a tcpcb is closed.
  This for now the problem isn't observed.
  
  Submitted by:	rrs

Modified:
  head/sys/kern/kern_timeout.c

Modified: head/sys/kern/kern_timeout.c
==============================================================================
--- head/sys/kern/kern_timeout.c	Tue Aug 16 21:32:05 2016	(r304243)
+++ head/sys/kern/kern_timeout.c	Tue Aug 16 21:55:34 2016	(r304244)
@@ -1061,7 +1061,7 @@ callout_reset_sbt_on(struct callout *c, 
 		 */
 		if (c->c_lock != NULL && !cc_exec_cancel(cc, direct))
 			cancelled = cc_exec_cancel(cc, direct) = true;
-		if (cc_exec_waiting(cc, direct)) {
+		if (cc_exec_waiting(cc, direct) || cc_exec_drain(cc, dir)) {
 			/*
 			 * Someone has called callout_drain to kill this
 			 * callout.  Don't reschedule.