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, 90 insertions, 0 deletions

diff --git a/drivers/interconnect/imx/imx8mn.c b/drivers/interconnect/imx/imx8mn.c
new file mode 100644
index 000000000..535fae791
--- /dev/null
+++ b/drivers/interconnect/imx/imx8mn.c
@@ -0,0 +1,90 @@
+// SPDX-License-Identifier: GPL-2.0
+/*
+ * Interconnect framework driver for i.MX8MN SoC
+ *
+ * Copyright (c) 2019-2020, NXP
+ */
+
+#include <linux/module.h>
+#include <linux/platform_device.h>
+#include <dt-bindings/interconnect/imx8mn.h>
+
+#include "imx.h"
+
+static const struct imx_icc_node_adj_desc imx8mn_dram_adj = {
+	.bw_mul = 1,
+	.bw_div = 4,
+	.phandle_name = "fsl,ddrc",
+};
+
+static const struct imx_icc_node_adj_desc imx8mn_noc_adj = {
+	.bw_mul = 1,
+	.bw_div = 4,
+	.main_noc = true,
+};
+
+/*
+ * Describe bus masters, slaves and connections between them
+ *
+ * This is a simplified subset of the bus diagram, there are several other
+ * PL301 nics which are skipped/merged into PL301_MAIN
+ */
+static struct imx_icc_node_desc nodes[] = {
+	DEFINE_BUS_INTERCONNECT("NOC", IMX8MN_ICN_NOC, &imx8mn_noc_adj,
+			IMX8MN_ICS_DRAM, IMX8MN_ICN_MAIN),
+
+	DEFINE_BUS_SLAVE("DRAM", IMX8MN_ICS_DRAM, &imx8mn_dram_adj),
+	DEFINE_BUS_SLAVE("OCRAM", IMX8MN_ICS_OCRAM, NULL),
+	DEFINE_BUS_MASTER("A53", IMX8MN_ICM_A53, IMX8MN_ICN_NOC),
+
+	/* GPUMIX */
+	DEFINE_BUS_MASTER("GPU", IMX8MN_ICM_GPU, IMX8MN_ICN_GPU),
+	DEFINE_BUS_INTERCONNECT("PL301_GPU", IMX8MN_ICN_GPU, NULL, IMX8MN_ICN_NOC),
+
+	/* DISPLAYMIX */
+	DEFINE_BUS_MASTER("CSI1", IMX8MN_ICM_CSI1, IMX8MN_ICN_MIPI),
+	DEFINE_BUS_MASTER("CSI2", IMX8MN_ICM_CSI2, IMX8MN_ICN_MIPI),
+	DEFINE_BUS_MASTER("ISI", IMX8MN_ICM_ISI, IMX8MN_ICN_MIPI),
+	DEFINE_BUS_MASTER("LCDIF", IMX8MN_ICM_LCDIF, IMX8MN_ICN_MIPI),
+	DEFINE_BUS_INTERCONNECT("PL301_MIPI", IMX8MN_ICN_MIPI, NULL, IMX8MN_ICN_NOC),
+
+	/* USB goes straight to NOC */
+	DEFINE_BUS_MASTER("USB", IMX8MN_ICM_USB, IMX8MN_ICN_NOC),
+
+	/* Audio */
+	DEFINE_BUS_MASTER("SDMA2", IMX8MN_ICM_SDMA2, IMX8MN_ICN_AUDIO),
+	DEFINE_BUS_MASTER("SDMA3", IMX8MN_ICM_SDMA3, IMX8MN_ICN_AUDIO),
+	DEFINE_BUS_INTERCONNECT("PL301_AUDIO", IMX8MN_ICN_AUDIO, NULL, IMX8MN_ICN_MAIN),
+
+	/* Ethernet */
+	DEFINE_BUS_MASTER("ENET", IMX8MN_ICM_ENET, IMX8MN_ICN_ENET),
+	DEFINE_BUS_INTERCONNECT("PL301_ENET", IMX8MN_ICN_ENET, NULL, IMX8MN_ICN_MAIN),
+
+	/* Other */
+	DEFINE_BUS_MASTER("SDMA1", IMX8MN_ICM_SDMA1, IMX8MN_ICN_MAIN),
+	DEFINE_BUS_MASTER("NAND", IMX8MN_ICM_NAND, IMX8MN_ICN_MAIN),
+	DEFINE_BUS_MASTER("USDHC1", IMX8MN_ICM_USDHC1, IMX8MN_ICN_MAIN),
+	DEFINE_BUS_MASTER("USDHC2", IMX8MN_ICM_USDHC2, IMX8MN_ICN_MAIN),
+	DEFINE_BUS_MASTER("USDHC3", IMX8MN_ICM_USDHC3, IMX8MN_ICN_MAIN),
+	DEFINE_BUS_INTERCONNECT("PL301_MAIN", IMX8MN_ICN_MAIN, NULL,
+			IMX8MN_ICN_NOC, IMX8MN_ICS_OCRAM),
+};
+
+static int imx8mn_icc_probe(struct platform_device *pdev)
+{
+	return imx_icc_register(pdev, nodes, ARRAY_SIZE(nodes), NULL);
+}
+
+static struct platform_driver imx8mn_icc_driver = {
+	.probe = imx8mn_icc_probe,
+	.remove = imx_icc_unregister,
+	.driver = {
+		.name = "imx8mn-interconnect",
+	},
+};
+
+module_platform_driver(imx8mn_icc_driver);
+MODULE_ALIAS("platform:imx8mn-interconnect");
+MODULE_AUTHOR("Leonard Crestez <leonard.crestez@nxp.com>");
+MODULE_DESCRIPTION("Interconnect framework driver for i.MX8MN SoC");
+MODULE_LICENSE("GPL v2");