dma-buf: handle testing kthreads creation failure

kthread creation may possibly fail inside race_signal_callback(). In
such a case stop the already started threads, put the already taken
references to them and return with error code.

Found by Linux Verification Center (linuxtesting.org).

Fixes: 2989f6451084 ("dma-buf: Add selftests for dma-fence")
Cc: stable@vger.kernel.org
Signed-off-by: Fedor Pchelkin <pchelkin@ispras.ru>
Reviewed-by: T.J. Mercier <tjmercier@google.com>
Link: https://patchwork.freedesktop.org/patch/msgid/20240522181308.841686-1-pchelkin@ispras.ru
Signed-off-by: Christian König <christian.koenig@amd.com>

diff --git a/drivers/dma-buf/st-dma-fence.c b/drivers/dma-buf/st-dma-fence.c
index b7c6f7ea9e0c83910b5a7d5001c25e0b96fa7492..6a1bfcd0cc21081cb42db82b3c61032ad2e401b2 100644 (file)
--- 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_put(t[i].task);
+                               return ret;
+                       }
                        get_task_struct(t[i].task);
                }