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, 116 insertions, 0 deletions

diff --git a/arch/mips/cobalt/setup.c b/arch/mips/cobalt/setup.c
new file mode 100644
index 000000000..9a266bf78
--- /dev/null
+++ b/arch/mips/cobalt/setup.c
@@ -0,0 +1,116 @@
+/*
+ * Setup pointers to hardware dependent routines.
+ *
+ * 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.
+ *
+ * Copyright (C) 1996, 1997, 2004, 05 by Ralf Baechle (ralf@linux-mips.org)
+ * Copyright (C) 2001, 2002, 2003 by Liam Davies (ldavies@agile.tv)
+ *
+ */
+#include <linux/init.h>
+#include <linux/interrupt.h>
+#include <linux/io.h>
+#include <linux/ioport.h>
+#include <linux/memblock.h>
+#include <linux/pm.h>
+
+#include <asm/bootinfo.h>
+#include <asm/reboot.h>
+#include <asm/setup.h>
+#include <asm/gt64120.h>
+
+#include <cobalt.h>
+
+const char *get_system_type(void)
+{
+	switch (cobalt_board_id) {
+		case COBALT_BRD_ID_QUBE1:
+			return "Cobalt Qube";
+		case COBALT_BRD_ID_RAQ1:
+			return "Cobalt RaQ";
+		case COBALT_BRD_ID_QUBE2:
+			return "Cobalt Qube2";
+		case COBALT_BRD_ID_RAQ2:
+			return "Cobalt RaQ2";
+	}
+	return "MIPS Cobalt";
+}
+
+/*
+ * Cobalt doesn't have PS/2 keyboard/mouse interfaces,
+ * keyboard controller is never used.
+ * Also PCI-ISA bridge DMA controller is never used.
+ */
+static struct resource cobalt_reserved_resources[] = {
+	{	/* dma1 */
+		.start	= 0x00,
+		.end	= 0x1f,
+		.name	= "reserved",
+		.flags	= IORESOURCE_BUSY | IORESOURCE_IO,
+	},
+	{	/* keyboard */
+		.start	= 0x60,
+		.end	= 0x6f,
+		.name	= "reserved",
+		.flags	= IORESOURCE_BUSY | IORESOURCE_IO,
+	},
+	{	/* dma page reg */
+		.start	= 0x80,
+		.end	= 0x8f,
+		.name	= "reserved",
+		.flags	= IORESOURCE_BUSY | IORESOURCE_IO,
+	},
+	{	/* dma2 */
+		.start	= 0xc0,
+		.end	= 0xdf,
+		.name	= "reserved",
+		.flags	= IORESOURCE_BUSY | IORESOURCE_IO,
+	},
+};
+
+void __init plat_mem_setup(void)
+{
+	int i;
+
+	_machine_restart = cobalt_machine_restart;
+	_machine_halt = cobalt_machine_halt;
+	pm_power_off = cobalt_machine_halt;
+
+	set_io_port_base(CKSEG1ADDR(GT_DEF_PCI0_IO_BASE));
+
+	/* I/O port resource */
+	ioport_resource.end = 0x01ffffff;
+
+	/* These resources have been reserved by VIA SuperI/O chip. */
+	for (i = 0; i < ARRAY_SIZE(cobalt_reserved_resources); i++)
+		request_resource(&ioport_resource, cobalt_reserved_resources + i);
+}
+
+/*
+ * Prom init. We read our one and only communication with the firmware.
+ * Grab the amount of installed memory.
+ * Better boot loaders (CoLo) pass a command line too :-)
+ */
+
+void __init prom_init(void)
+{
+	unsigned long memsz;
+	int argc, i;
+	char **argv;
+
+	memsz = fw_arg0 & 0x7fff0000;
+	argc = fw_arg0 & 0x0000ffff;
+	argv = (char **)fw_arg1;
+
+	for (i = 1; i < argc; i++) {
+		strlcat(arcs_cmdline, argv[i], COMMAND_LINE_SIZE);
+		if (i < (argc - 1))
+			strlcat(arcs_cmdline, " ", COMMAND_LINE_SIZE);
+	}
+
+	memblock_add(0, memsz);
+
+	setup_8250_early_printk_port(CKSEG1ADDR(0x1c800000), 0, 0);
+}