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, 100 insertions, 0 deletions

diff --git a/arch/mips/sgi-ip32/ip32-setup.c b/arch/mips/sgi-ip32/ip32-setup.c
new file mode 100644
index 000000000..c2ebc4bbd
--- /dev/null
+++ b/arch/mips/sgi-ip32/ip32-setup.c
@@ -0,0 +1,100 @@
+/*
+ * IP32 basic setup
+ *
+ * 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) 2000 Harald Koerfgen
+ * Copyright (C) 2002, 2003, 2005 Ilya A. Volynets
+ * Copyright (C) 2006 Ralf Baechle <ralf@linux-mips.org>
+ */
+#include <linux/console.h>
+#include <linux/init.h>
+#include <linux/interrupt.h>
+#include <linux/param.h>
+#include <linux/sched.h>
+#include <linux/string.h>
+
+#include <asm/bootinfo.h>
+#include <asm/mipsregs.h>
+#include <asm/mmu_context.h>
+#include <asm/sgialib.h>
+#include <asm/time.h>
+#include <asm/traps.h>
+#include <asm/io.h>
+#include <asm/ip32/crime.h>
+#include <asm/ip32/mace.h>
+#include <asm/ip32/ip32_ints.h>
+
+#include "ip32-common.h"
+
+#ifdef CONFIG_SGI_O2MACE_ETH
+/*
+ * This is taken care of in here 'cause they say using Arc later on is
+ * problematic
+ */
+extern char o2meth_eaddr[8];
+static inline unsigned char str2hexnum(unsigned char c)
+{
+	if (c >= '0' && c <= '9')
+		return c - '0';
+	if (c >= 'a' && c <= 'f')
+		return c - 'a' + 10;
+	return 0; /* foo */
+}
+
+static inline void str2eaddr(unsigned char *ea, unsigned char *str)
+{
+	int i;
+
+	for (i = 0; i < 6; i++) {
+		unsigned char num;
+
+		if(*str == ':')
+			str++;
+		num = str2hexnum(*str++) << 4;
+		num |= (str2hexnum(*str++));
+		ea[i] = num;
+	}
+}
+#endif
+
+/* An arbitrary time; this can be decreased if reliability looks good */
+#define WAIT_MS 10
+
+void __init plat_time_init(void)
+{
+	printk(KERN_INFO "Calibrating system timer... ");
+	write_c0_count(0);
+	crime->timer = 0;
+	while (crime->timer < CRIME_MASTER_FREQ * WAIT_MS / 1000) ;
+	mips_hpt_frequency = read_c0_count() * 1000 / WAIT_MS;
+	printk("%d MHz CPU detected\n", mips_hpt_frequency * 2 / 1000000);
+}
+
+void __init plat_mem_setup(void)
+{
+	board_be_init = ip32_be_init;
+
+#ifdef CONFIG_SGI_O2MACE_ETH
+	{
+		char *mac = ArcGetEnvironmentVariable("eaddr");
+		str2eaddr(o2meth_eaddr, mac);
+	}
+#endif
+
+#if defined(CONFIG_SERIAL_CORE_CONSOLE)
+	{
+		char* con = ArcGetEnvironmentVariable("console");
+		if (con && *con == 'd') {
+			static char options[8] __initdata;
+			char *baud = ArcGetEnvironmentVariable("dbaud");
+			if (baud)
+				strscpy(options, baud);
+			add_preferred_console("ttyS", *(con + 1) == '2' ? 1 : 0,
+					      baud ? options : NULL);
+		}
+	}
+#endif
+}