From: David S. Miller <davem@davemloft.net>
Date: Fri, 17 Jul 2009 17:28:19 +0000 (-0700)
Subject: sparc: Fix cleanup crash in bbc_envctrl_cleanup()
X-Git-Tag: v2.6.31-rc9~16^2~9
X-Git-Url: http://ftp.safe.ca/?a=commitdiff_plain;ds=sidebyside;h=14d87e6c399f3942d63dff41447ff08a615d9a6b;p=safe%2Fjmp%2Flinux-2.6

sparc: Fix cleanup crash in bbc_envctrl_cleanup()

If kthread_run() fails or never gets to run we'll have NULL
or a pointer encoded error in kenvctrld_task, rather than
a legitimate task pointer.

So this makes bbc_envctrl_cleanup() crash as it passed this
bogus pointer into kthread_stop().

Reported-by: BERTRAND Joël <joel.bertrand@systella.fr>
Signed-off-by: David S. Miller <davem@davemloft.net>
---

diff --git a/drivers/sbus/char/bbc_envctrl.c b/drivers/sbus/char/bbc_envctrl.c
index 15dab96..7c815d3 100644
--- a/drivers/sbus/char/bbc_envctrl.c
+++ b/drivers/sbus/char/bbc_envctrl.c
@@ -537,8 +537,12 @@ int bbc_envctrl_init(struct bbc_i2c_bus *bp)
 	}
 	if (temp_index != 0 && fan_index != 0) {
 		kenvctrld_task = kthread_run(kenvctrld, NULL, "kenvctrld");
-		if (IS_ERR(kenvctrld_task))
-			return PTR_ERR(kenvctrld_task);
+		if (IS_ERR(kenvctrld_task)) {
+			int err = PTR_ERR(kenvctrld_task);
+
+			kenvctrld_task = NULL;
+			return err;
+		}
 	}
 
 	return 0;
@@ -561,7 +565,8 @@ void bbc_envctrl_cleanup(struct bbc_i2c_bus *bp)
 	struct bbc_cpu_temperature *tp, *tpos;
 	struct bbc_fan_control *fp, *fpos;
 
-	kthread_stop(kenvctrld_task);
+	if (kenvctrld_task)
+		kthread_stop(kenvctrld_task);
 
 	list_for_each_entry_safe(tp, tpos, &bp->temps, bp_list) {
 		list_del(&tp->bp_list);