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, 50 insertions, 0 deletions

diff --git a/arch/m68k/coldfire/reset.c b/arch/m68k/coldfire/reset.c
new file mode 100644
index 000000000..6e5f8ab39
--- /dev/null
+++ b/arch/m68k/coldfire/reset.c
@@ -0,0 +1,50 @@
+/*
+ * reset.c  -- common ColdFire SoC reset support
+ *
+ * (C) Copyright 2012, Greg Ungerer <gerg@uclinux.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/kernel.h>
+#include <linux/init.h>
+#include <linux/io.h>
+#include <asm/machdep.h>
+#include <asm/coldfire.h>
+#include <asm/mcfsim.h>
+
+/*
+ *	There are 2 common methods amongst the ColdFure parts for reseting
+ *	the CPU. But there are couple of exceptions, the 5272 and the 547x
+ *	have something completely special to them, and we let their specific
+ *	subarch code handle them.
+ */
+
+#ifdef MCFSIM_SYPCR
+static void mcf_cpu_reset(void)
+{
+	local_irq_disable();
+	/* Set watchdog to soft reset, and enabled */
+	mcf_write8(0xc0, MCFSIM_SYPCR);
+	for (;;)
+		/* wait for watchdog to timeout */;
+}
+#endif
+
+#ifdef MCF_RCR
+static void mcf_cpu_reset(void)
+{
+	local_irq_disable();
+	mcf_write8(MCF_RCR_SWRESET, MCF_RCR);
+}
+#endif
+
+static int __init mcf_setup_reset(void)
+{
+	mach_reset = mcf_cpu_reset;
+	return 0;
+}
+
+arch_initcall(mcf_setup_reset);