linux-wandboard

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

[ Upstream commit 91e630d9ae6de6f740ef7c8176736eb55366833e ]

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>
Cc: stable@vger.kernel.org
Signed-off-by: Sasha Levin <alexander.levin@verizon.com>