svn commit: r334087 - head/sys/kern

[Mateusz Guzik]

Author: mjg
Date: Wed May 23 10:13:17 2018
New Revision: 334087
URL: https://svnweb.freebsd.org/changeset/base/334087

Log:
  Remove incorrect owepreempt assertion added in r334062
  
  Yet another preemption request hitting between the counter being 0
  and the check being reached will result in the flag no longer being
  set.
  
  Note the situation was already present prior to r334062 and is harmless.
  
  Reported by:	pho
  Reviewed by:	kib

Modified:
  head/sys/kern/kern_switch.c

Modified: head/sys/kern/kern_switch.c
==============================================================================
--- head/sys/kern/kern_switch.c	Wed May 23 10:03:09 2018	(r334086)
+++ head/sys/kern/kern_switch.c	Wed May 23 10:13:17 2018	(r334087)
@@ -215,9 +215,13 @@ critical_exit_preempt(void)
 	struct thread *td;
 	int flags;
 
+	/*
+	 * If td_critnest is 0, it is possible that we are going to get
+	 * preempted again before reaching the code below. This happens
+	 * rarely and is harmless. However, this means td_owepreempt may
+	 * now be unset.
+	 */
 	td = curthread;
-	KASSERT(td->td_owepreempt != 0,
-	    ("critical_exit: td_owepreempt == 0"));
 	if (td->td_critnest != 0)
 		return;
 	if (kdb_active)