FAILED: patch "[PATCH] dma-buf: handle testing kthreads creation failure" failed to apply to 5.10-stable tree

[<gregkh@linuxfoundation.org>]

The patch below does not apply to the 5.10-stable tree.
If someone wants it applied there, or to any other stable or longterm
tree, then please email the backport, including the original git commit
id to <stable@vger.kernel.org>.

To reproduce the conflict and resubmit, you may use the following commands:

git fetch https://git.kernel.org/pub/scm/linux/kernel/git/stable/linux.git/ linux-5.10.y
git checkout FETCH_HEAD
git cherry-pick -x 6cb05d89fd62a76a9b74bd16211fb0930e89fea8
# <resolve conflicts, build, test, etc.>
git commit -s
git send-email --to '<stable@vger.kernel.org>' --in-reply-to '2024061838-making-gumminess-1815@gregkh' --subject-prefix 'PATCH 5.10.y' HEAD^..

Possible dependencies:

6cb05d89fd62 ("dma-buf: handle testing kthreads creation failure")

thanks,

greg k-h

------------------ original commit in Linus's tree ------------------

From 6cb05d89fd62a76a9b74bd16211fb0930e89fea8 Mon Sep 17 00:00:00 2001
From: Fedor Pchelkin <pchelkin@ispras.ru>
Date: Wed, 22 May 2024 21:13:08 +0300
Subject: [PATCH] dma-buf: handle testing kthreads creation failure
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Content-Transfer-Encoding: 8bit

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 b7c6f7ea9e0c..6a1bfcd0cc21 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_put(t[i].task);
+				return ret;
+			}
 			get_task_struct(t[i].task);
 		}