[PATCH] dma-buf: handle testing kthreads creation failure

[Fedor Pchelkin]

kthread creation may possibly fail inside race_signal_callback(). In
such case stop the already started threads and return with error code.

Found by Linux Verification Center (linuxtesting.org).

Fixes: 2989f6451084 ("dma-buf: Add selftests for dma-fence")
Cc: stable@xxxxxxxxxxxxxxx
Signed-off-by: Fedor Pchelkin <pchelkin@xxxxxxxxx>
---
 drivers/dma-buf/st-dma-fence.c | 6 ++++++
 1 file changed, 6 insertions(+)

diff --git a/drivers/dma-buf/st-dma-fence.c b/drivers/dma-buf/st-dma-fence.c
index b7c6f7ea9e0c..ab1ec4631578 100644
--- a/drivers/dma-buf/st-dma-fence.c
+++ b/drivers/dma-buf/st-dma-fence.c
@@ -540,6 +540,12 @@ static int race_signal_callback(void *arg)
 			t[i].before = pass;
 			t[i].task = kthread_run(thread_signal_callback, &t[i],
 						"dma-fence:%d", i);
+			if (IS_ERR(t[i].task)) {
+				ret = PTR_ERR(t[i].task);
+				while (--i >= 0)
+					kthread_stop(t[i].task);
+				return ret;
+			}
 			get_task_struct(t[i].task);
 		}
 
-- 
2.39.2