The patch below does not apply to the 5.4-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-5.4.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 '2024061839-donated-dropper-a091@gregkh' --subject-prefix 'PATCH 5.4.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 MIME-Version: 1.0 Content-Type: text/plain; charset=UTF-8 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-pchelk... 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); }