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, 307 insertions, 0 deletions

diff --git a/drivers/acpi/acpica/utbuffer.c b/drivers/acpi/acpica/utbuffer.c
new file mode 100644
index 000000000..4193ceb93
--- /dev/null
+++ b/drivers/acpi/acpica/utbuffer.c
@@ -0,0 +1,307 @@
+// SPDX-License-Identifier: BSD-3-Clause OR GPL-2.0
+/******************************************************************************
+ *
+ * Module Name: utbuffer - Buffer dump routines
+ *
+ * Copyright (C) 2000 - 2026, Intel Corp.
+ *
+ *****************************************************************************/
+
+#include <acpi/acpi.h>
+#include "accommon.h"
+
+#define _COMPONENT          ACPI_UTILITIES
+ACPI_MODULE_NAME("utbuffer")
+
+/*******************************************************************************
+ *
+ * FUNCTION:    acpi_ut_dump_buffer
+ *
+ * PARAMETERS:  buffer              - Buffer to dump
+ *              count               - Amount to dump, in bytes
+ *              display             - BYTE, WORD, DWORD, or QWORD display:
+ *                                      DB_BYTE_DISPLAY
+ *                                      DB_WORD_DISPLAY
+ *                                      DB_DWORD_DISPLAY
+ *                                      DB_QWORD_DISPLAY
+ *              base_offset         - Beginning buffer offset (display only)
+ *
+ * RETURN:      None
+ *
+ * DESCRIPTION: Generic dump buffer in both hex and ascii.
+ *
+ ******************************************************************************/
+void acpi_ut_dump_buffer(u8 *buffer, u32 count, u32 display, u32 base_offset)
+{
+	u32 i = 0;
+	u32 j;
+	u32 temp32;
+	u8 buf_char;
+	u32 display_data_only = display & DB_DISPLAY_DATA_ONLY;
+
+	display &= ~DB_DISPLAY_DATA_ONLY;
+	if (!buffer) {
+		acpi_os_printf("Null Buffer Pointer in DumpBuffer!\n");
+		return;
+	}
+
+	if ((count < 4) || (count & 0x01)) {
+		display = DB_BYTE_DISPLAY;
+	}
+
+	/* Nasty little dump buffer routine! */
+
+	while (i < count) {
+
+		/* Print current offset */
+
+		if (!display_data_only) {
+			acpi_os_printf("%8.4X: ", (base_offset + i));
+		}
+
+		/* Print 16 hex chars */
+
+		for (j = 0; j < 16;) {
+			if (i + j >= count) {
+
+				/* Dump fill spaces */
+
+				acpi_os_printf("%*s", ((display * 2) + 1), " ");
+				j += display;
+				continue;
+			}
+
+			switch (display) {
+			case DB_BYTE_DISPLAY:
+			default:	/* Default is BYTE display */
+
+				acpi_os_printf("%02X ",
+					       buffer[(acpi_size)i + j]);
+				break;
+
+			case DB_WORD_DISPLAY:
+
+				ACPI_MOVE_16_TO_32(&temp32,
+						   &buffer[(acpi_size)i + j]);
+				acpi_os_printf("%04X ", temp32);
+				break;
+
+			case DB_DWORD_DISPLAY:
+
+				ACPI_MOVE_32_TO_32(&temp32,
+						   &buffer[(acpi_size)i + j]);
+				acpi_os_printf("%08X ", temp32);
+				break;
+
+			case DB_QWORD_DISPLAY:
+
+				ACPI_MOVE_32_TO_32(&temp32,
+						   &buffer[(acpi_size)i + j]);
+				acpi_os_printf("%08X", temp32);
+
+				ACPI_MOVE_32_TO_32(&temp32,
+						   &buffer[(acpi_size)i + j +
+							   4]);
+				acpi_os_printf("%08X ", temp32);
+				break;
+			}
+
+			j += display;
+		}
+
+		/*
+		 * Print the ASCII equivalent characters but watch out for the bad
+		 * unprintable ones (printable chars are 0x20 through 0x7E)
+		 */
+		if (!display_data_only) {
+			acpi_os_printf(" ");
+			for (j = 0; j < 16; j++) {
+				if (i + j >= count) {
+					acpi_os_printf("\n");
+					return;
+				}
+
+				/*
+				 * Add comment characters so rest of line is ignored when
+				 * compiled
+				 */
+				if (j == 0) {
+					acpi_os_printf("// ");
+				}
+
+				buf_char = buffer[(acpi_size)i + j];
+				if (isprint(buf_char)) {
+					acpi_os_printf("%c", buf_char);
+				} else {
+					acpi_os_printf(".");
+				}
+			}
+
+			/* Done with that line. */
+
+			acpi_os_printf("\n");
+		}
+		i += 16;
+	}
+
+	return;
+}
+
+/*******************************************************************************
+ *
+ * FUNCTION:    acpi_ut_debug_dump_buffer
+ *
+ * PARAMETERS:  buffer              - Buffer to dump
+ *              count               - Amount to dump, in bytes
+ *              display             - BYTE, WORD, DWORD, or QWORD display:
+ *                                      DB_BYTE_DISPLAY
+ *                                      DB_WORD_DISPLAY
+ *                                      DB_DWORD_DISPLAY
+ *                                      DB_QWORD_DISPLAY
+ *              component_ID        - Caller's component ID
+ *
+ * RETURN:      None
+ *
+ * DESCRIPTION: Generic dump buffer in both hex and ascii.
+ *
+ ******************************************************************************/
+
+void
+acpi_ut_debug_dump_buffer(u8 *buffer, u32 count, u32 display, u32 component_id)
+{
+
+	/* Only dump the buffer if tracing is enabled */
+
+	if (!((ACPI_LV_TABLES & acpi_dbg_level) &&
+	      (component_id & acpi_dbg_layer))) {
+		return;
+	}
+
+	acpi_ut_dump_buffer(buffer, count, display, 0);
+}
+
+#ifdef ACPI_APPLICATION
+/*******************************************************************************
+ *
+ * FUNCTION:    acpi_ut_dump_buffer_to_file
+ *
+ * PARAMETERS:  file                - File descriptor
+ *              buffer              - Buffer to dump
+ *              count               - Amount to dump, in bytes
+ *              display             - BYTE, WORD, DWORD, or QWORD display:
+ *                                      DB_BYTE_DISPLAY
+ *                                      DB_WORD_DISPLAY
+ *                                      DB_DWORD_DISPLAY
+ *                                      DB_QWORD_DISPLAY
+ *              base_offset         - Beginning buffer offset (display only)
+ *
+ * RETURN:      None
+ *
+ * DESCRIPTION: Generic dump buffer in both hex and ascii to a file.
+ *
+ ******************************************************************************/
+
+void
+acpi_ut_dump_buffer_to_file(ACPI_FILE file,
+			    u8 *buffer, u32 count, u32 display, u32 base_offset)
+{
+	u32 i = 0;
+	u32 j;
+	u32 temp32;
+	u8 buf_char;
+
+	if (!buffer) {
+		fprintf(file, "Null Buffer Pointer in DumpBuffer!\n");
+		return;
+	}
+
+	if ((count < 4) || (count & 0x01)) {
+		display = DB_BYTE_DISPLAY;
+	}
+
+	/* Nasty little dump buffer routine! */
+
+	while (i < count) {
+
+		/* Print current offset */
+
+		fprintf(file, "%8.4X: ", (base_offset + i));
+
+		/* Print 16 hex chars */
+
+		for (j = 0; j < 16;) {
+			if (i + j >= count) {
+
+				/* Dump fill spaces */
+
+				fprintf(file, "%*s", ((display * 2) + 1), " ");
+				j += display;
+				continue;
+			}
+
+			switch (display) {
+			case DB_BYTE_DISPLAY:
+			default:	/* Default is BYTE display */
+
+				fprintf(file, "%02X ",
+					buffer[(acpi_size)i + j]);
+				break;
+
+			case DB_WORD_DISPLAY:
+
+				ACPI_MOVE_16_TO_32(&temp32,
+						   &buffer[(acpi_size)i + j]);
+				fprintf(file, "%04X ", temp32);
+				break;
+
+			case DB_DWORD_DISPLAY:
+
+				ACPI_MOVE_32_TO_32(&temp32,
+						   &buffer[(acpi_size)i + j]);
+				fprintf(file, "%08X ", temp32);
+				break;
+
+			case DB_QWORD_DISPLAY:
+
+				ACPI_MOVE_32_TO_32(&temp32,
+						   &buffer[(acpi_size)i + j]);
+				fprintf(file, "%08X", temp32);
+
+				ACPI_MOVE_32_TO_32(&temp32,
+						   &buffer[(acpi_size)i + j +
+							   4]);
+				fprintf(file, "%08X ", temp32);
+				break;
+			}
+
+			j += display;
+		}
+
+		/*
+		 * Print the ASCII equivalent characters but watch out for the bad
+		 * unprintable ones (printable chars are 0x20 through 0x7E)
+		 */
+		fprintf(file, " ");
+		for (j = 0; j < 16; j++) {
+			if (i + j >= count) {
+				fprintf(file, "\n");
+				return;
+			}
+
+			buf_char = buffer[(acpi_size)i + j];
+			if (isprint(buf_char)) {
+				fprintf(file, "%c", buf_char);
+			} else {
+				fprintf(file, ".");
+			}
+		}
+
+		/* Done with that line. */
+
+		fprintf(file, "\n");
+		i += 16;
+	}
+
+	return;
+}
+#endif