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, 143 insertions, 0 deletions

diff --git a/arch/m68k/coldfire/stmark2.c b/arch/m68k/coldfire/stmark2.c
new file mode 100644
index 000000000..254520790
--- /dev/null
+++ b/arch/m68k/coldfire/stmark2.c
@@ -0,0 +1,143 @@
+/*
+ * stmark2.c -- Support for Kernelspace AMCORE open board
+ *
+ * (C) Copyright 2026, Angelo Dureghello <angelo@kernel-space.org>
+ *
+ * This file is subject to the terms and conditions of the GNU General Public
+ * License.  See the file COPYING in the main directory of this archive
+ * for more details.
+ */
+
+#include <linux/ioport.h>
+#include <linux/platform_device.h>
+#include <linux/mtd/partitions.h>
+#include <linux/spi/spi.h>
+#include <linux/spi/spi-fsl-dspi.h>
+#include <linux/spi/flash.h>
+#include <linux/dma-mapping.h>
+#include <asm/mcfsim.h>
+
+/*
+ * Partitioning of parallel NOR flash (39VF3201B)
+ */
+static struct mtd_partition stmark2_partitions[] = {
+	{
+		.name = "U-Boot (1024K)",
+		.size = 0x100000,
+		.offset = 0x0
+	}, {
+		.name = "Kernel+initramfs (7168K)",
+		.size = 0x700000,
+		.offset = MTDPART_OFS_APPEND
+	}, {
+		.name = "Flash Free Space (8192K)",
+		.size = MTDPART_SIZ_FULL,
+		.offset = MTDPART_OFS_APPEND
+	}
+};
+
+static struct flash_platform_data stmark2_spi_flash_data = {
+	.name = "is25lp128",
+	.parts = stmark2_partitions,
+	.nr_parts = ARRAY_SIZE(stmark2_partitions),
+	.type = "is25lp128",
+};
+
+static struct spi_board_info stmark2_board_info[] __initdata = {
+	{
+		.modalias = "m25p80",
+		.max_speed_hz = 5000000,
+		.bus_num = 0,
+		.chip_select = 1,
+		.platform_data = &stmark2_spi_flash_data,
+		.mode = SPI_MODE_3,
+	}
+};
+
+/* SPI controller data, SPI (0) */
+static struct fsl_dspi_platform_data dspi_spi0_info = {
+	.cs_num = 4,
+	.bus_num = 0,
+	.sck_cs_delay = 100,
+	.cs_sck_delay = 100,
+};
+
+static struct resource dspi_spi0_resource[] = {
+	DEFINE_RES_MEM(MCFDSPI_BASE0, 0x100),
+	DEFINE_RES_IRQ(MCF_IRQ_DSPI0),
+	DEFINE_RES_DMA(12),
+	DEFINE_RES_DMA(13),
+};
+
+static u64 stmark2_dspi_mask = DMA_BIT_MASK(32);
+
+/* SPI controller, id = bus number */
+static struct platform_device dspi_spi0_device = {
+	.name = "fsl-dspi",
+	.id = 0,
+	.num_resources = ARRAY_SIZE(dspi_spi0_resource),
+	.resource = dspi_spi0_resource,
+	.dev = {
+		.platform_data = &dspi_spi0_info,
+		.dma_mask = &stmark2_dspi_mask,
+		.coherent_dma_mask = DMA_BIT_MASK(32),
+	},
+};
+
+static struct resource dac0_resource = DEFINE_RES_MEM(MCFDAC_BASE0, 0x100);
+
+static struct platform_device dac0_device = {
+	.name = "mcfdac",
+	.id = 0,
+	.num_resources = 1,
+	.resource = &dac0_resource,
+};
+
+static struct resource dac1_resource = DEFINE_RES_MEM(MCFDAC_BASE1, 0x100);
+
+static struct platform_device dac1_device = {
+	.name = "mcfdac",
+	.id = 1,
+	.num_resources = 1,
+	.resource = &dac1_resource,
+};
+
+static struct platform_device *stmark2_devices[] __initdata = {
+	&dspi_spi0_device,
+	&dac0_device,
+	&dac1_device,
+};
+
+/*
+ * Note: proper pin-mux setup is mandatory for proper SPI functionality.
+ */
+static int __init init_stmark2(void)
+{
+	u16 val;
+
+	/* DSPI0, all pins as DSPI, and using CS1 */
+	mcf_write8(0x80, MCFGPIO_PAR_DSPIOWL);
+	mcf_write8(0xfc, MCFGPIO_PAR_DSPIOWH);
+
+	/* Board gpio setup */
+	mcf_write8(0x00, MCFGPIO_PAR_BE);
+	mcf_write8(0x00, MCFGPIO_PAR_FBCTL);
+	mcf_write8(0x00, MCFGPIO_PAR_CS);
+
+	/* CAN pads */
+	mcf_write8(0x50, MCFGPIO_PAR_CANI2C);
+
+	val = mcf_read16(MCF_CCM_MISCCR2);
+	val &= ~(MCF_CCM_MISCCR2_ADC3_EN | MCF_CCM_MISCCR2_ADC7_EN);
+	val |= MCF_CCM_MISCCR2_DAC0_SEL | MCF_CCM_MISCCR2_DAC1_SEL;
+	mcf_write16(val, MCF_CCM_MISCCR2);
+
+	platform_add_devices(stmark2_devices, ARRAY_SIZE(stmark2_devices));
+
+	spi_register_board_info(stmark2_board_info,
+				ARRAY_SIZE(stmark2_board_info));
+
+	return 0;
+}
+
+device_initcall(init_stmark2);