From: Vladimir Zapolskiy <vz@mleia.com>
Date: Wed, 9 Mar 2016 23:22:19 +0000 (+0200)
Subject: dm log writes: fix check of kthread_run() return value
X-Git-Tag: v4.7.5~77
X-Git-Url: http://git.ipfire.org/cgi-bin/gitweb.cgi?a=commitdiff_plain;h=0e470b8e18d240f2accf305e3a13469a46bd8504;p=thirdparty%2Fkernel%2Fstable.git

dm log writes: fix check of kthread_run() return value

commit 91e630d9ae6de6f740ef7c8176736eb55366833e upstream.

The kthread_run() function returns either a valid task_struct or
ERR_PTR() value, check for NULL is invalid.  This change fixes potential
for oops, e.g. in OOM situation.

Signed-off-by: Vladimir Zapolskiy <vz@mleia.com>
Signed-off-by: Mike Snitzer <snitzer@redhat.com>
Signed-off-by: Greg Kroah-Hartman <gregkh@linuxfoundation.org>
---

diff --git a/drivers/md/dm-log-writes.c b/drivers/md/dm-log-writes.c
index 608302e222af0..7b1f2f2759b01 100644
--- a/drivers/md/dm-log-writes.c
+++ b/drivers/md/dm-log-writes.c
@@ -456,9 +456,9 @@ static int log_writes_ctr(struct dm_target *ti, unsigned int argc, char **argv)
 		goto bad;
 	}
 
-	ret = -EINVAL;
 	lc->log_kthread = kthread_run(log_writes_kthread, lc, "log-write");
-	if (!lc->log_kthread) {
+	if (IS_ERR(lc->log_kthread)) {
+		ret = PTR_ERR(lc->log_kthread);
 		ti->error = "Couldn't alloc kthread";
 		dm_put_device(ti, lc->dev);
 		dm_put_device(ti, lc->logdev);