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, 494 insertions, 0 deletions

diff --git a/drivers/acpi/acpica/utmath.c b/drivers/acpi/acpica/utmath.c
new file mode 100644
index 000000000..2c2c6bc1f
--- /dev/null
+++ b/drivers/acpi/acpica/utmath.c
@@ -0,0 +1,494 @@
+// SPDX-License-Identifier: BSD-3-Clause OR GPL-2.0
+/*******************************************************************************
+ *
+ * Module Name: utmath - Integer math support routines
+ *
+ ******************************************************************************/
+
+#include <acpi/acpi.h>
+#include "accommon.h"
+
+#define _COMPONENT          ACPI_UTILITIES
+ACPI_MODULE_NAME("utmath")
+
+/* Structures used only for 64-bit divide */
+typedef struct uint64_struct {
+	u32 lo;
+	u32 hi;
+
+} uint64_struct;
+
+typedef union uint64_overlay {
+	u64 full;
+	struct uint64_struct part;
+
+} uint64_overlay;
+
+/*
+ * Optional support for 64-bit double-precision integer multiply and shift.
+ * This code is configurable and is implemented in order to support 32-bit
+ * kernel environments where a 64-bit double-precision math library is not
+ * available.
+ */
+#ifndef ACPI_USE_NATIVE_MATH64
+
+/*******************************************************************************
+ *
+ * FUNCTION:    acpi_ut_short_multiply
+ *
+ * PARAMETERS:  multiplicand        - 64-bit multiplicand
+ *              multiplier          - 32-bit multiplier
+ *              out_product         - Pointer to where the product is returned
+ *
+ * DESCRIPTION: Perform a short multiply.
+ *
+ ******************************************************************************/
+
+acpi_status
+acpi_ut_short_multiply(u64 multiplicand, u32 multiplier, u64 *out_product)
+{
+	union uint64_overlay multiplicand_ovl;
+	union uint64_overlay product;
+	u32 carry32;
+
+	ACPI_FUNCTION_TRACE(ut_short_multiply);
+
+	multiplicand_ovl.full = multiplicand;
+
+	/*
+	 * The Product is 64 bits, the carry is always 32 bits,
+	 * and is generated by the second multiply.
+	 */
+	ACPI_MUL_64_BY_32(0, multiplicand_ovl.part.hi, multiplier,
+			  product.part.hi, carry32);
+
+	ACPI_MUL_64_BY_32(0, multiplicand_ovl.part.lo, multiplier,
+			  product.part.lo, carry32);
+
+	product.part.hi += carry32;
+
+	/* Return only what was requested */
+
+	if (out_product) {
+		*out_product = product.full;
+	}
+
+	return_ACPI_STATUS(AE_OK);
+}
+
+/*******************************************************************************
+ *
+ * FUNCTION:    acpi_ut_short_shift_left
+ *
+ * PARAMETERS:  operand             - 64-bit shift operand
+ *              count               - 32-bit shift count
+ *              out_result          - Pointer to where the result is returned
+ *
+ * DESCRIPTION: Perform a short left shift.
+ *
+ ******************************************************************************/
+
+acpi_status acpi_ut_short_shift_left(u64 operand, u32 count, u64 *out_result)
+{
+	union uint64_overlay operand_ovl;
+
+	ACPI_FUNCTION_TRACE(ut_short_shift_left);
+
+	operand_ovl.full = operand;
+
+	if ((count & 63) >= 32) {
+		operand_ovl.part.hi = operand_ovl.part.lo;
+		operand_ovl.part.lo = 0;
+		count = (count & 63) - 32;
+	}
+	ACPI_SHIFT_LEFT_64_BY_32(operand_ovl.part.hi,
+				 operand_ovl.part.lo, count);
+
+	/* Return only what was requested */
+
+	if (out_result) {
+		*out_result = operand_ovl.full;
+	}
+
+	return_ACPI_STATUS(AE_OK);
+}
+
+/*******************************************************************************
+ *
+ * FUNCTION:    acpi_ut_short_shift_right
+ *
+ * PARAMETERS:  operand             - 64-bit shift operand
+ *              count               - 32-bit shift count
+ *              out_result          - Pointer to where the result is returned
+ *
+ * DESCRIPTION: Perform a short right shift.
+ *
+ ******************************************************************************/
+
+acpi_status acpi_ut_short_shift_right(u64 operand, u32 count, u64 *out_result)
+{
+	union uint64_overlay operand_ovl;
+
+	ACPI_FUNCTION_TRACE(ut_short_shift_right);
+
+	operand_ovl.full = operand;
+
+	if ((count & 63) >= 32) {
+		operand_ovl.part.lo = operand_ovl.part.hi;
+		operand_ovl.part.hi = 0;
+		count = (count & 63) - 32;
+	}
+	ACPI_SHIFT_RIGHT_64_BY_32(operand_ovl.part.hi,
+				  operand_ovl.part.lo, count);
+
+	/* Return only what was requested */
+
+	if (out_result) {
+		*out_result = operand_ovl.full;
+	}
+
+	return_ACPI_STATUS(AE_OK);
+}
+#else
+
+/*******************************************************************************
+ *
+ * FUNCTION:    acpi_ut_short_multiply
+ *
+ * PARAMETERS:  See function headers above
+ *
+ * DESCRIPTION: Native version of the ut_short_multiply function.
+ *
+ ******************************************************************************/
+
+acpi_status
+acpi_ut_short_multiply(u64 multiplicand, u32 multiplier, u64 *out_product)
+{
+
+	ACPI_FUNCTION_TRACE(ut_short_multiply);
+
+	/* Return only what was requested */
+
+	if (out_product) {
+		*out_product = multiplicand * multiplier;
+	}
+
+	return_ACPI_STATUS(AE_OK);
+}
+
+/*******************************************************************************
+ *
+ * FUNCTION:    acpi_ut_short_shift_left
+ *
+ * PARAMETERS:  See function headers above
+ *
+ * DESCRIPTION: Native version of the ut_short_shift_left function.
+ *
+ ******************************************************************************/
+
+acpi_status acpi_ut_short_shift_left(u64 operand, u32 count, u64 *out_result)
+{
+
+	ACPI_FUNCTION_TRACE(ut_short_shift_left);
+
+	/* Return only what was requested */
+
+	if (out_result) {
+		*out_result = operand << count;
+	}
+
+	return_ACPI_STATUS(AE_OK);
+}
+
+/*******************************************************************************
+ *
+ * FUNCTION:    acpi_ut_short_shift_right
+ *
+ * PARAMETERS:  See function headers above
+ *
+ * DESCRIPTION: Native version of the ut_short_shift_right function.
+ *
+ ******************************************************************************/
+
+acpi_status acpi_ut_short_shift_right(u64 operand, u32 count, u64 *out_result)
+{
+
+	ACPI_FUNCTION_TRACE(ut_short_shift_right);
+
+	/* Return only what was requested */
+
+	if (out_result) {
+		*out_result = operand >> count;
+	}
+
+	return_ACPI_STATUS(AE_OK);
+}
+#endif
+
+/*
+ * Optional support for 64-bit double-precision integer divide. This code
+ * is configurable and is implemented in order to support 32-bit kernel
+ * environments where a 64-bit double-precision math library is not available.
+ *
+ * Support for a more normal 64-bit divide/modulo (with check for a divide-
+ * by-zero) appears after this optional section of code.
+ */
+#ifndef ACPI_USE_NATIVE_DIVIDE
+
+/*******************************************************************************
+ *
+ * FUNCTION:    acpi_ut_short_divide
+ *
+ * PARAMETERS:  dividend            - 64-bit dividend
+ *              divisor             - 32-bit divisor
+ *              out_quotient        - Pointer to where the quotient is returned
+ *              out_remainder       - Pointer to where the remainder is returned
+ *
+ * RETURN:      Status (Checks for divide-by-zero)
+ *
+ * DESCRIPTION: Perform a short (maximum 64 bits divided by 32 bits)
+ *              divide and modulo. The result is a 64-bit quotient and a
+ *              32-bit remainder.
+ *
+ ******************************************************************************/
+
+acpi_status
+acpi_ut_short_divide(u64 dividend,
+		     u32 divisor, u64 *out_quotient, u32 *out_remainder)
+{
+	union uint64_overlay dividend_ovl;
+	union uint64_overlay quotient;
+	u32 remainder32;
+
+	ACPI_FUNCTION_TRACE(ut_short_divide);
+
+	/* Always check for a zero divisor */
+
+	if (divisor == 0) {
+		ACPI_ERROR((AE_INFO, "Divide by zero"));
+		return_ACPI_STATUS(AE_AML_DIVIDE_BY_ZERO);
+	}
+
+	dividend_ovl.full = dividend;
+
+	/*
+	 * The quotient is 64 bits, the remainder is always 32 bits,
+	 * and is generated by the second divide.
+	 */
+	ACPI_DIV_64_BY_32(0, dividend_ovl.part.hi, divisor,
+			  quotient.part.hi, remainder32);
+
+	ACPI_DIV_64_BY_32(remainder32, dividend_ovl.part.lo, divisor,
+			  quotient.part.lo, remainder32);
+
+	/* Return only what was requested */
+
+	if (out_quotient) {
+		*out_quotient = quotient.full;
+	}
+	if (out_remainder) {
+		*out_remainder = remainder32;
+	}
+
+	return_ACPI_STATUS(AE_OK);
+}
+
+/*******************************************************************************
+ *
+ * FUNCTION:    acpi_ut_divide
+ *
+ * PARAMETERS:  in_dividend         - Dividend
+ *              in_divisor          - Divisor
+ *              out_quotient        - Pointer to where the quotient is returned
+ *              out_remainder       - Pointer to where the remainder is returned
+ *
+ * RETURN:      Status (Checks for divide-by-zero)
+ *
+ * DESCRIPTION: Perform a divide and modulo.
+ *
+ ******************************************************************************/
+
+acpi_status
+acpi_ut_divide(u64 in_dividend,
+	       u64 in_divisor, u64 *out_quotient, u64 *out_remainder)
+{
+	union uint64_overlay dividend;
+	union uint64_overlay divisor;
+	union uint64_overlay quotient;
+	union uint64_overlay remainder;
+	union uint64_overlay normalized_dividend;
+	union uint64_overlay normalized_divisor;
+	u32 partial1;
+	union uint64_overlay partial2;
+	union uint64_overlay partial3;
+
+	ACPI_FUNCTION_TRACE(ut_divide);
+
+	/* Always check for a zero divisor */
+
+	if (in_divisor == 0) {
+		ACPI_ERROR((AE_INFO, "Divide by zero"));
+		return_ACPI_STATUS(AE_AML_DIVIDE_BY_ZERO);
+	}
+
+	divisor.full = in_divisor;
+	dividend.full = in_dividend;
+	if (divisor.part.hi == 0) {
+		/*
+		 * 1) Simplest case is where the divisor is 32 bits, we can
+		 * just do two divides
+		 */
+		remainder.part.hi = 0;
+
+		/*
+		 * The quotient is 64 bits, the remainder is always 32 bits,
+		 * and is generated by the second divide.
+		 */
+		ACPI_DIV_64_BY_32(0, dividend.part.hi, divisor.part.lo,
+				  quotient.part.hi, partial1);
+
+		ACPI_DIV_64_BY_32(partial1, dividend.part.lo, divisor.part.lo,
+				  quotient.part.lo, remainder.part.lo);
+	}
+
+	else {
+		/*
+		 * 2) The general case where the divisor is a full 64 bits
+		 * is more difficult
+		 */
+		quotient.part.hi = 0;
+		normalized_dividend = dividend;
+		normalized_divisor = divisor;
+
+		/* Normalize the operands (shift until the divisor is < 32 bits) */
+
+		do {
+			ACPI_SHIFT_RIGHT_64(normalized_divisor.part.hi,
+					    normalized_divisor.part.lo);
+			ACPI_SHIFT_RIGHT_64(normalized_dividend.part.hi,
+					    normalized_dividend.part.lo);
+
+		} while (normalized_divisor.part.hi != 0);
+
+		/* Partial divide */
+
+		ACPI_DIV_64_BY_32(normalized_dividend.part.hi,
+				  normalized_dividend.part.lo,
+				  normalized_divisor.part.lo, quotient.part.lo,
+				  partial1);
+
+		/*
+		 * The quotient is always 32 bits, and simply requires
+		 * adjustment. The 64-bit remainder must be generated.
+		 */
+		partial1 = quotient.part.lo * divisor.part.hi;
+		partial2.full = (u64) quotient.part.lo * divisor.part.lo;
+		partial3.full = (u64) partial2.part.hi + partial1;
+
+		remainder.part.hi = partial3.part.lo;
+		remainder.part.lo = partial2.part.lo;
+
+		if (partial3.part.hi == 0) {
+			if (partial3.part.lo >= dividend.part.hi) {
+				if (partial3.part.lo == dividend.part.hi) {
+					if (partial2.part.lo > dividend.part.lo) {
+						quotient.part.lo--;
+						remainder.full -= divisor.full;
+					}
+				} else {
+					quotient.part.lo--;
+					remainder.full -= divisor.full;
+				}
+			}
+
+			remainder.full = remainder.full - dividend.full;
+			remainder.part.hi = (u32)-((s32)remainder.part.hi);
+			remainder.part.lo = (u32)-((s32)remainder.part.lo);
+
+			if (remainder.part.lo) {
+				remainder.part.hi--;
+			}
+		}
+	}
+
+	/* Return only what was requested */
+
+	if (out_quotient) {
+		*out_quotient = quotient.full;
+	}
+	if (out_remainder) {
+		*out_remainder = remainder.full;
+	}
+
+	return_ACPI_STATUS(AE_OK);
+}
+
+#else
+
+/*******************************************************************************
+ *
+ * FUNCTION:    acpi_ut_short_divide, acpi_ut_divide
+ *
+ * PARAMETERS:  See function headers above
+ *
+ * DESCRIPTION: Native versions of the ut_divide functions. Use these if either
+ *              1) The target is a 64-bit platform and therefore 64-bit
+ *                 integer math is supported directly by the machine.
+ *              2) The target is a 32-bit or 16-bit platform, and the
+ *                 double-precision integer math library is available to
+ *                 perform the divide.
+ *
+ ******************************************************************************/
+
+acpi_status
+acpi_ut_short_divide(u64 in_dividend,
+		     u32 divisor, u64 *out_quotient, u32 *out_remainder)
+{
+
+	ACPI_FUNCTION_TRACE(ut_short_divide);
+
+	/* Always check for a zero divisor */
+
+	if (divisor == 0) {
+		ACPI_ERROR((AE_INFO, "Divide by zero"));
+		return_ACPI_STATUS(AE_AML_DIVIDE_BY_ZERO);
+	}
+
+	/* Return only what was requested */
+
+	if (out_quotient) {
+		*out_quotient = in_dividend / divisor;
+	}
+	if (out_remainder) {
+		*out_remainder = (u32) (in_dividend % divisor);
+	}
+
+	return_ACPI_STATUS(AE_OK);
+}
+
+acpi_status
+acpi_ut_divide(u64 in_dividend,
+	       u64 in_divisor, u64 *out_quotient, u64 *out_remainder)
+{
+	ACPI_FUNCTION_TRACE(ut_divide);
+
+	/* Always check for a zero divisor */
+
+	if (in_divisor == 0) {
+		ACPI_ERROR((AE_INFO, "Divide by zero"));
+		return_ACPI_STATUS(AE_AML_DIVIDE_BY_ZERO);
+	}
+
+	/* Return only what was requested */
+
+	if (out_quotient) {
+		*out_quotient = in_dividend / in_divisor;
+	}
+	if (out_remainder) {
+		*out_remainder = in_dividend % in_divisor;
+	}
+
+	return_ACPI_STATUS(AE_OK);
+}
+
+#endif