ftrace: Synchronize the initialization of ftrace_opsgrafted

There's some internal state that ftrace_ops needs to have set, but since
it can be declared outside of the ftrace.c code, it calls
ftrace_ops_init() on the ops in every global function. The issue is that
if two tasks call it on the same ops at the same time it is possible to
have the initialization of one corrupt the initialization of the other
call.

Create a ops_mutex to use to synchronize every initialization of the
ftrace_ops. The mutex is taken within checking the ftrace_ops flag that
states it was initializied but the flag is checked again after the mutex
has been taken. Checking first outside the mutex allows it to shortcut
having to take the mutex. But then the check needs to be done again after
the mute is taken in case of races.

Cc: stable@vger.kernel.org
Link: https://patch.msgid.link/20260902095501.6b59af20@gandalf.local.home
Fixes: f04f24fb7e48d ("ftrace, kprobes: Fix a deadlock on ftrace_regex_lock")
Reported-by: sashiko-bot@kernel.org
Close: https://lore.kernel.org/all/20260829025528.49A831F000E9@smtp.kernel.org/
Signed-off-by: Steven Rostedt <rostedt@goodmis.org>

1 files changed, 135 insertions, 0 deletions

diff --git a/drivers/crypto/qce/dma.c b/drivers/crypto/qce/dma.c
new file mode 100644
index 000000000..68cafd474
--- /dev/null
+++ b/drivers/crypto/qce/dma.c
@@ -0,0 +1,135 @@
+// SPDX-License-Identifier: GPL-2.0-only
+/*
+ * Copyright (c) 2012-2014, The Linux Foundation. All rights reserved.
+ */
+
+#include <linux/device.h>
+#include <linux/dmaengine.h>
+#include <crypto/scatterwalk.h>
+
+#include "dma.h"
+
+static void qce_dma_release(void *data)
+{
+	struct qce_dma_data *dma = data;
+
+	dma_release_channel(dma->txchan);
+	dma_release_channel(dma->rxchan);
+	kfree(dma->result_buf);
+}
+
+int devm_qce_dma_request(struct device *dev, struct qce_dma_data *dma)
+{
+	int ret;
+
+	dma->txchan = dma_request_chan(dev, "tx");
+	if (IS_ERR(dma->txchan))
+		return dev_err_probe(dev, PTR_ERR(dma->txchan),
+				     "Failed to get TX DMA channel\n");
+
+	dma->rxchan = dma_request_chan(dev, "rx");
+	if (IS_ERR(dma->rxchan)) {
+		ret = dev_err_probe(dev, PTR_ERR(dma->rxchan),
+				    "Failed to get RX DMA channel\n");
+		goto error_rx;
+	}
+
+	dma->result_buf = kmalloc(QCE_RESULT_BUF_SZ + QCE_IGNORE_BUF_SZ,
+				  GFP_KERNEL);
+	if (!dma->result_buf) {
+		ret = -ENOMEM;
+		goto error_nomem;
+	}
+
+	dma->ignore_buf = dma->result_buf + QCE_RESULT_BUF_SZ;
+
+	return devm_add_action_or_reset(dev, qce_dma_release, dma);
+
+error_nomem:
+	dma_release_channel(dma->rxchan);
+error_rx:
+	dma_release_channel(dma->txchan);
+	return ret;
+}
+
+struct scatterlist *
+qce_sgtable_add(struct sg_table *sgt, struct scatterlist *new_sgl,
+		unsigned int max_len)
+{
+	struct scatterlist *sg = sgt->sgl, *sg_last = NULL;
+	unsigned int new_len;
+
+	while (sg) {
+		if (!sg_page(sg))
+			break;
+		sg = sg_next(sg);
+	}
+
+	if (!sg)
+		return ERR_PTR(-EINVAL);
+
+	while (new_sgl && sg && max_len) {
+		new_len = new_sgl->length > max_len ? max_len : new_sgl->length;
+		sg_set_page(sg, sg_page(new_sgl), new_len, new_sgl->offset);
+		sg_last = sg;
+		sg = sg_next(sg);
+		new_sgl = sg_next(new_sgl);
+		max_len -= new_len;
+	}
+
+	return sg_last;
+}
+
+static int qce_dma_prep_sg(struct dma_chan *chan, struct scatterlist *sg,
+			   int nents, unsigned long flags,
+			   enum dma_transfer_direction dir,
+			   dma_async_tx_callback cb, void *cb_param)
+{
+	struct dma_async_tx_descriptor *desc;
+	dma_cookie_t cookie;
+
+	if (!sg || !nents)
+		return -EINVAL;
+
+	desc = dmaengine_prep_slave_sg(chan, sg, nents, dir, flags);
+	if (!desc)
+		return -EINVAL;
+
+	desc->callback = cb;
+	desc->callback_param = cb_param;
+	cookie = dmaengine_submit(desc);
+
+	return dma_submit_error(cookie);
+}
+
+int qce_dma_prep_sgs(struct qce_dma_data *dma, struct scatterlist *rx_sg,
+		     int rx_nents, struct scatterlist *tx_sg, int tx_nents,
+		     dma_async_tx_callback cb, void *cb_param)
+{
+	struct dma_chan *rxchan = dma->rxchan;
+	struct dma_chan *txchan = dma->txchan;
+	unsigned long flags = DMA_PREP_INTERRUPT | DMA_CTRL_ACK;
+	int ret;
+
+	ret = qce_dma_prep_sg(rxchan, rx_sg, rx_nents, flags, DMA_MEM_TO_DEV,
+			     NULL, NULL);
+	if (ret)
+		return ret;
+
+	return qce_dma_prep_sg(txchan, tx_sg, tx_nents, flags, DMA_DEV_TO_MEM,
+			       cb, cb_param);
+}
+
+void qce_dma_issue_pending(struct qce_dma_data *dma)
+{
+	dma_async_issue_pending(dma->rxchan);
+	dma_async_issue_pending(dma->txchan);
+}
+
+int qce_dma_terminate_all(struct qce_dma_data *dma)
+{
+	int ret;
+
+	ret = dmaengine_terminate_all(dma->rxchan);
+	return ret ?: dmaengine_terminate_all(dma->txchan);
+}