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, 244 insertions, 0 deletions

diff --git a/arch/arm/mach-omap2/pm-debug.c b/arch/arm/mach-omap2/pm-debug.c
new file mode 100644
index 000000000..b43eab987
--- /dev/null
+++ b/arch/arm/mach-omap2/pm-debug.c
@@ -0,0 +1,244 @@
+// SPDX-License-Identifier: GPL-2.0-only
+/*
+ * OMAP Power Management debug routines
+ *
+ * Copyright (C) 2005 Texas Instruments, Inc.
+ * Copyright (C) 2006-2008 Nokia Corporation
+ *
+ * Written by:
+ * Richard Woodruff <r-woodruff2@ti.com>
+ * Tony Lindgren
+ * Juha Yrjola
+ * Amit Kucheria <amit.kucheria@nokia.com>
+ * Igor Stoppa <igor.stoppa@nokia.com>
+ * Jouni Hogander
+ *
+ * Based on pm.c for omap2
+ */
+
+#include <linux/kernel.h>
+#include <linux/sched.h>
+#include <linux/sched/clock.h>
+#include <linux/clk.h>
+#include <linux/err.h>
+#include <linux/io.h>
+#include <linux/module.h>
+#include <linux/slab.h>
+
+#include "clock.h"
+#include "powerdomain.h"
+#include "clockdomain.h"
+
+#include "soc.h"
+#include "cm2xxx_3xxx.h"
+#include "prm2xxx_3xxx.h"
+#include "pm.h"
+
+#ifdef CONFIG_DEBUG_FS
+#include <linux/debugfs.h>
+#include <linux/seq_file.h>
+
+static int pm_dbg_init_done;
+
+static int pm_dbg_init(void);
+
+static const char pwrdm_state_names[][PWRDM_MAX_PWRSTS] = {
+	"OFF",
+	"RET",
+	"INA",
+	"ON"
+};
+
+void pm_dbg_update_time(struct powerdomain *pwrdm, int prev)
+{
+	s64 t;
+
+	if (!pm_dbg_init_done)
+		return ;
+
+	/* Update timer for previous state */
+	t = sched_clock();
+
+	pwrdm->state_timer[prev] += t - pwrdm->timer;
+
+	pwrdm->timer = t;
+}
+
+static int clkdm_dbg_show_counter(struct clockdomain *clkdm, void *user)
+{
+	struct seq_file *s = (struct seq_file *)user;
+
+	if (strcmp(clkdm->name, "emu_clkdm") == 0 ||
+		strcmp(clkdm->name, "wkup_clkdm") == 0 ||
+		strncmp(clkdm->name, "dpll", 4) == 0)
+		return 0;
+
+	seq_printf(s, "%s->%s (%d)\n", clkdm->name, clkdm->pwrdm.ptr->name,
+		   clkdm->usecount);
+
+	return 0;
+}
+
+static int pwrdm_dbg_show_counter(struct powerdomain *pwrdm, void *user)
+{
+	struct seq_file *s = (struct seq_file *)user;
+	int i;
+
+	if (strcmp(pwrdm->name, "emu_pwrdm") == 0 ||
+		strcmp(pwrdm->name, "wkup_pwrdm") == 0 ||
+		strncmp(pwrdm->name, "dpll", 4) == 0)
+		return 0;
+
+	if (pwrdm->state != pwrdm_read_pwrst(pwrdm))
+		printk(KERN_ERR "pwrdm state mismatch(%s) %d != %d\n",
+			pwrdm->name, pwrdm->state, pwrdm_read_pwrst(pwrdm));
+
+	seq_printf(s, "%s (%s)", pwrdm->name,
+			pwrdm_state_names[pwrdm->state]);
+	for (i = 0; i < PWRDM_MAX_PWRSTS; i++)
+		seq_printf(s, ",%s:%d", pwrdm_state_names[i],
+			pwrdm->state_counter[i]);
+
+	seq_printf(s, ",RET-LOGIC-OFF:%d", pwrdm->ret_logic_off_counter);
+	for (i = 0; i < pwrdm->banks; i++)
+		seq_printf(s, ",RET-MEMBANK%d-OFF:%d", i + 1,
+				pwrdm->ret_mem_off_counter[i]);
+
+	seq_putc(s, '\n');
+	return 0;
+}
+
+static int pwrdm_dbg_show_timer(struct powerdomain *pwrdm, void *user)
+{
+	struct seq_file *s = (struct seq_file *)user;
+	int i;
+
+	if (strcmp(pwrdm->name, "emu_pwrdm") == 0 ||
+		strcmp(pwrdm->name, "wkup_pwrdm") == 0 ||
+		strncmp(pwrdm->name, "dpll", 4) == 0)
+		return 0;
+
+	pwrdm_state_switch(pwrdm);
+
+	seq_printf(s, "%s (%s)", pwrdm->name,
+		pwrdm_state_names[pwrdm->state]);
+
+	for (i = 0; i < 4; i++)
+		seq_printf(s, ",%s:%lld", pwrdm_state_names[i],
+			pwrdm->state_timer[i]);
+
+	seq_putc(s, '\n');
+	return 0;
+}
+
+static int pm_dbg_counters_show(struct seq_file *s, void *unused)
+{
+	pwrdm_for_each(pwrdm_dbg_show_counter, s);
+	clkdm_for_each(clkdm_dbg_show_counter, s);
+
+	return 0;
+}
+DEFINE_SHOW_ATTRIBUTE(pm_dbg_counters);
+
+static int pm_dbg_timers_show(struct seq_file *s, void *unused)
+{
+	pwrdm_for_each(pwrdm_dbg_show_timer, s);
+	return 0;
+}
+DEFINE_SHOW_ATTRIBUTE(pm_dbg_timers);
+
+static int pwrdm_suspend_get(void *data, u64 *val)
+{
+	int ret = -EINVAL;
+
+	if (cpu_is_omap34xx())
+		ret = omap3_pm_get_suspend_state((struct powerdomain *)data);
+	*val = ret;
+
+	if (ret >= 0)
+		return 0;
+	return *val;
+}
+
+static int pwrdm_suspend_set(void *data, u64 val)
+{
+	if (cpu_is_omap34xx())
+		return omap3_pm_set_suspend_state(
+			(struct powerdomain *)data, (int)val);
+	return -EINVAL;
+}
+
+DEFINE_DEBUGFS_ATTRIBUTE(pwrdm_suspend_fops, pwrdm_suspend_get,
+			  pwrdm_suspend_set, "%llu\n");
+
+static int __init pwrdms_setup(struct powerdomain *pwrdm, void *dir)
+{
+	int i;
+	s64 t;
+	struct dentry *d;
+
+	t = sched_clock();
+
+	for (i = 0; i < 4; i++)
+		pwrdm->state_timer[i] = 0;
+
+	pwrdm->timer = t;
+
+	if (strncmp(pwrdm->name, "dpll", 4) == 0)
+		return 0;
+
+	d = debugfs_create_dir(pwrdm->name, (struct dentry *)dir);
+	debugfs_create_file("suspend", S_IRUGO|S_IWUSR, d, pwrdm,
+			    &pwrdm_suspend_fops);
+
+	return 0;
+}
+
+static int option_get(void *data, u64 *val)
+{
+	u32 *option = data;
+
+	*val = *option;
+
+	return 0;
+}
+
+static int option_set(void *data, u64 val)
+{
+	u32 *option = data;
+
+	*option = val;
+
+	if (option == &enable_off_mode) {
+		if (cpu_is_omap34xx())
+			omap3_pm_off_mode_enable(val);
+	}
+
+	return 0;
+}
+
+DEFINE_SIMPLE_ATTRIBUTE(pm_dbg_option_fops, option_get, option_set, "%llu\n");
+
+static int __init pm_dbg_init(void)
+{
+	struct dentry *d;
+
+	if (pm_dbg_init_done)
+		return 0;
+
+	d = debugfs_create_dir("pm_debug", NULL);
+
+	debugfs_create_file("count", 0444, d, NULL, &pm_dbg_counters_fops);
+	debugfs_create_file("time", 0444, d, NULL, &pm_dbg_timers_fops);
+
+	pwrdm_for_each(pwrdms_setup, (void *)d);
+
+	debugfs_create_file("enable_off_mode", S_IRUGO | S_IWUSR, d,
+			    &enable_off_mode, &pm_dbg_option_fops);
+	pm_dbg_init_done = 1;
+
+	return 0;
+}
+omap_arch_initcall(pm_dbg_init);
+
+#endif