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, 142 insertions, 0 deletions

diff --git a/drivers/interconnect/mediatek/mt8183.c b/drivers/interconnect/mediatek/mt8183.c
new file mode 100644
index 000000000..ed607a8b8
--- /dev/null
+++ b/drivers/interconnect/mediatek/mt8183.c
@@ -0,0 +1,142 @@
+// SPDX-License-Identifier: GPL-2.0
+/*
+ * Copyright (c) 2021 MediaTek Inc.
+ * Copyright (c) 2024 Collabora Ltd.
+ *                    AngeloGioacchino Del Regno <angelogioacchino.delregno@collabora.com>
+ */
+
+#include <linux/device.h>
+#include <linux/interconnect.h>
+#include <linux/interconnect-provider.h>
+#include <linux/module.h>
+#include <linux/platform_device.h>
+#include <dt-bindings/interconnect/mediatek,mt8183.h>
+
+#include "icc-emi.h"
+
+static struct mtk_icc_node ddr_emi = {
+	.name = "ddr-emi",
+	.id = SLAVE_DDR_EMI,
+	.ep = 1,
+};
+
+static struct mtk_icc_node mcusys = {
+	.name = "mcusys",
+	.id = MASTER_MCUSYS,
+	.ep = 0,
+	.num_links = 1,
+	.links = { SLAVE_DDR_EMI }
+};
+
+static struct mtk_icc_node gpu = {
+	.name = "gpu",
+	.id = MASTER_MFG,
+	.ep = 0,
+	.num_links = 1,
+	.links = { SLAVE_DDR_EMI }
+};
+
+static struct mtk_icc_node mmsys = {
+	.name = "mmsys",
+	.id = MASTER_MMSYS,
+	.ep = 0,
+	.num_links = 1,
+	.links = { SLAVE_DDR_EMI }
+};
+
+static struct mtk_icc_node mm_vpu = {
+	.name = "mm-vpu",
+	.id = MASTER_MM_VPU,
+	.ep = 0,
+	.num_links = 1,
+	.links = { MASTER_MMSYS }
+};
+
+static struct mtk_icc_node mm_disp = {
+	.name = "mm-disp",
+	.id = MASTER_MM_DISP,
+	.ep = 0,
+	.num_links = 1,
+	.links = { MASTER_MMSYS }
+};
+
+static struct mtk_icc_node mm_vdec = {
+	.name = "mm-vdec",
+	.id = MASTER_MM_VDEC,
+	.ep = 0,
+	.num_links = 1,
+	.links = { MASTER_MMSYS }
+};
+
+static struct mtk_icc_node mm_venc = {
+	.name = "mm-venc",
+	.id = MASTER_MM_VENC,
+	.ep = 0,
+	.num_links = 1,
+	.links = { MASTER_MMSYS }
+};
+
+static struct mtk_icc_node mm_cam = {
+	.name = "mm-cam",
+	.id = MASTER_MM_CAM,
+	.ep = 0,
+	.num_links = 1,
+	.links = { MASTER_MMSYS }
+};
+
+static struct mtk_icc_node mm_img = {
+	.name = "mm-img",
+	.id = MASTER_MM_IMG,
+	.ep = 0,
+	.num_links = 1,
+	.links = { MASTER_MMSYS }
+};
+
+static struct mtk_icc_node mm_mdp = {
+	.name = "mm-mdp",
+	.id = MASTER_MM_MDP,
+	.ep = 0,
+	.num_links = 1,
+	.links = { MASTER_MMSYS }
+};
+
+static struct mtk_icc_node *mt8183_emi_icc_nodes[] = {
+	[SLAVE_DDR_EMI] = &ddr_emi,
+	[MASTER_MCUSYS] = &mcusys,
+	[MASTER_MFG] = &gpu,
+	[MASTER_MMSYS] = &mmsys,
+	[MASTER_MM_VPU] = &mm_vpu,
+	[MASTER_MM_DISP] = &mm_disp,
+	[MASTER_MM_VDEC] = &mm_vdec,
+	[MASTER_MM_VENC] = &mm_venc,
+	[MASTER_MM_CAM] = &mm_cam,
+	[MASTER_MM_IMG] = &mm_img,
+	[MASTER_MM_MDP] = &mm_mdp
+};
+
+static const struct mtk_icc_desc mt8183_emi_icc = {
+	.nodes = mt8183_emi_icc_nodes,
+	.num_nodes = ARRAY_SIZE(mt8183_emi_icc_nodes),
+};
+
+static const struct of_device_id mtk_mt8183_emi_icc_of_match[] = {
+	{ .compatible = "mediatek,mt8183-emi", .data = &mt8183_emi_icc },
+	{ /* sentinel */ },
+};
+MODULE_DEVICE_TABLE(of, mtk_mt8183_emi_icc_of_match);
+
+static struct platform_driver mtk_emi_icc_mt8183_driver = {
+	.driver = {
+		.name = "emi-icc-mt8183",
+		.of_match_table = mtk_mt8183_emi_icc_of_match,
+		.sync_state = icc_sync_state,
+	},
+	.probe = mtk_emi_icc_probe,
+	.remove = mtk_emi_icc_remove,
+
+};
+module_platform_driver(mtk_emi_icc_mt8183_driver);
+
+MODULE_AUTHOR("AngeloGioacchino Del Regno <angelogioacchino.delregno@collabora.com>");
+MODULE_DESCRIPTION("MediaTek MT8183 EMI ICC driver");
+MODULE_LICENSE("GPL");