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, 60 insertions, 0 deletions

diff --git a/drivers/usb/dwc3/io.h b/drivers/usb/dwc3/io.h
new file mode 100644
index 000000000..cad9a2ae1
--- /dev/null
+++ b/drivers/usb/dwc3/io.h
@@ -0,0 +1,60 @@
+/* SPDX-License-Identifier: GPL-2.0 */
+/*
+ * io.h - DesignWare USB3 DRD IO Header
+ *
+ * Copyright (C) 2010-2011 Texas Instruments Incorporated - https://www.ti.com
+ *
+ * Authors: Felipe Balbi <balbi@ti.com>,
+ *	    Sebastian Andrzej Siewior <bigeasy@linutronix.de>
+ */
+
+#ifndef __DRIVERS_USB_DWC3_IO_H
+#define __DRIVERS_USB_DWC3_IO_H
+
+#include <linux/io.h>
+#include "trace.h"
+#include "debug.h"
+#include "core.h"
+
+static inline u32 dwc3_readl(struct dwc3 *dwc, u32 offset)
+{
+	u32 value;
+	void __iomem *base = dwc->regs;
+
+	/*
+	 * We requested the mem region starting from the Globals address
+	 * space, see dwc3_probe in core.c.
+	 * However, the offsets are given starting from xHCI address space.
+	 */
+	value = readl(base + offset - DWC3_GLOBALS_REGS_START);
+
+	/*
+	 * When tracing we want to make it easy to find the correct address on
+	 * documentation, so we revert it back to the proper addresses, the
+	 * same way they are described on SNPS documentation
+	 */
+	trace_dwc3_readl(dwc, base - DWC3_GLOBALS_REGS_START, offset, value);
+
+	return value;
+}
+
+static inline void dwc3_writel(struct dwc3 *dwc, u32 offset, u32 value)
+{
+	void __iomem *base = dwc->regs;
+
+	/*
+	 * We requested the mem region starting from the Globals address
+	 * space, see dwc3_probe in core.c.
+	 * However, the offsets are given starting from xHCI address space.
+	 */
+	writel(value, base + offset - DWC3_GLOBALS_REGS_START);
+
+	/*
+	 * When tracing we want to make it easy to find the correct address on
+	 * documentation, so we revert it back to the proper addresses, the
+	 * same way they are described on SNPS documentation
+	 */
+	trace_dwc3_writel(dwc, base - DWC3_GLOBALS_REGS_START, offset, value);
+}
+
+#endif /* __DRIVERS_USB_DWC3_IO_H */