From 7ac89421b5a801d998dd60ee8cd0684bc6e83fcd Mon Sep 17 00:00:00 2001
From: Robert Mustacchi <rm@joyent.com>
Date: Sun, 3 Nov 2013 16:36:38 +0000
Subject: [PATCH] 4285 preemption leaves a context op behind Reviewed by: Bryan
 Cantrill <bryan@joyent.com> Reviewed by: Richard Lowe <richlowe@richlowe.net>
 Approved by: Dan McDonald <danmcd@nexenta.com>

---
 usr/src/uts/common/disp/thread.c |  8 ++++++++
 usr/src/uts/common/os/proc.c     | 10 ++++++++--
 2 files changed, 16 insertions(+), 2 deletions(-)

diff --git a/usr/src/uts/common/disp/thread.c b/usr/src/uts/common/disp/thread.c
index 5ed9110251..8998b6ea51 100644
--- a/usr/src/uts/common/disp/thread.c
+++ b/usr/src/uts/common/disp/thread.c
@@ -21,6 +21,7 @@
 
 /*
  * Copyright (c) 1991, 2010, Oracle and/or its affiliates. All rights reserved.
+ * Copyright (c) 2013, Joyent, Inc.  All rights reserved.
  */
 
 #include <sys/types.h>
@@ -1092,6 +1093,7 @@ removectx(
 	 */
 	mutex_enter(&t->t_ctx_lock);
 	prev_ctx = NULL;
+	kpreempt_disable();
 	for (ctx = t->t_ctx; ctx != NULL; ctx = ctx->next) {
 		if (ctx->save_op == save && ctx->restore_op == restore &&
 		    ctx->fork_op == fork && ctx->lwp_create_op == lwp_create &&
@@ -1105,11 +1107,13 @@ removectx(
 			if (ctx->free_op != NULL)
 				(ctx->free_op)(ctx->arg, 0);
 			kmem_free(ctx, sizeof (struct ctxop));
+			kpreempt_enable();
 			return (1);
 		}
 		prev_ctx = ctx;
 	}
 	mutex_exit(&t->t_ctx_lock);
+	kpreempt_enable();
 
 	return (0);
 }
@@ -1187,12 +1191,14 @@ freectx(kthread_t *t, int isexec)
 {
 	struct ctxop *ctx;
 
+	kpreempt_disable();
 	while ((ctx = t->t_ctx) != NULL) {
 		t->t_ctx = ctx->next;
 		if (ctx->free_op != NULL)
 			(ctx->free_op)(ctx->arg, isexec);
 		kmem_free(ctx, sizeof (struct ctxop));
 	}
+	kpreempt_enable();
 }
 
 /*
@@ -1209,12 +1215,14 @@ freectx_ctx(struct ctxop *ctx)
 
 	ASSERT(ctx != NULL);
 
+	kpreempt_disable();
 	do {
 		nctx = ctx->next;
 		if (ctx->free_op != NULL)
 			(ctx->free_op)(ctx->arg, 0);
 		kmem_free(ctx, sizeof (struct ctxop));
 	} while ((ctx = nctx) != NULL);
+	kpreempt_enable();
 }
 
 /*
diff --git a/usr/src/uts/common/os/proc.c b/usr/src/uts/common/os/proc.c
index 83563f34a9..3d4c82fcad 100644
--- a/usr/src/uts/common/os/proc.c
+++ b/usr/src/uts/common/os/proc.c
@@ -22,11 +22,12 @@
 /*
  * Copyright 2006 Sun Microsystems, Inc.  All rights reserved.
  * Use is subject to license terms.
+ * Copyright (c) 2013, Joyent, Inc.  All rights reserved.
  */
 
-#pragma ident	"%Z%%M%	%I%	%E% SMI"
-
 #include <sys/proc.h>
+#include <sys/cpuvar.h>
+#include <sys/disp.h>
 
 /*
  * Install process context ops for the current process.
@@ -70,6 +71,7 @@ removepctx(
 	struct pctxop *pctx, *prev_pctx;
 
 	prev_pctx = NULL;
+	kpreempt_disable();
 	for (pctx = p->p_pctx; pctx != NULL; pctx = pctx->next) {
 		if (pctx->save_op == save && pctx->restore_op == restore &&
 		    pctx->fork_op == fork &&
@@ -82,10 +84,12 @@ removepctx(
 			if (pctx->free_op != NULL)
 				(pctx->free_op)(pctx->arg, 0);
 			kmem_free(pctx, sizeof (struct pctxop));
+			kpreempt_enable();
 			return (1);
 		}
 		prev_pctx = pctx;
 	}
+	kpreempt_enable();
 	return (0);
 }
 
@@ -146,10 +150,12 @@ freepctx(proc_t *p, int isexec)
 {
 	struct pctxop *pctx;
 
+	kpreempt_disable();
 	while ((pctx = p->p_pctx) != NULL) {
 		p->p_pctx = pctx->next;
 		if (pctx->free_op != NULL)
 			(pctx->free_op)(pctx->arg, isexec);
 		kmem_free(pctx, sizeof (struct pctxop));
 	}
+	kpreempt_enable();
 }
-- 
2.11.4.GIT