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, 297 insertions, 0 deletions

diff --git a/tools/include/nolibc/arch-mips.h b/tools/include/nolibc/arch-mips.h
new file mode 100644
index 000000000..26ad413ce
--- /dev/null
+++ b/tools/include/nolibc/arch-mips.h
@@ -0,0 +1,297 @@
+/* SPDX-License-Identifier: LGPL-2.1 OR MIT */
+/*
+ * MIPS specific definitions for NOLIBC
+ * Copyright (C) 2017-2022 Willy Tarreau <w@1wt.eu>
+ */
+
+#ifndef _NOLIBC_ARCH_MIPS_H
+#define _NOLIBC_ARCH_MIPS_H
+
+#include <linux/unistd.h>
+
+#include "compiler.h"
+#include "crt.h"
+#include "std.h"
+
+#if !defined(_ABIO32) && !defined(_ABIN32) && !defined(_ABI64)
+#error Unsupported MIPS ABI
+#endif
+
+/* Syscalls for MIPS ABI O32 :
+ *   - WARNING! there's always a delayed slot!
+ *   - WARNING again, the syntax is different, registers take a '$' and numbers
+ *     do not.
+ *   - registers are 32-bit
+ *   - stack is 8-byte aligned
+ *   - syscall number is passed in v0 (starts at 0xfa0).
+ *   - arguments are in a0, a1, a2, a3, then the stack. The caller needs to
+ *     leave some room in the stack for the callee to save a0..a3 if needed.
+ *   - Many registers are clobbered, in fact only a0..a2 and s0..s8 are
+ *     preserved. See: https://www.linux-mips.org/wiki/Syscall as well as
+ *     scall32-o32.S in the kernel sources.
+ *   - the system call is performed by calling "syscall"
+ *   - syscall return comes in v0, and register a3 needs to be checked to know
+ *     if an error occurred, in which case errno is in v0.
+ *   - the arguments are cast to long and assigned into the target registers
+ *     which are then simply passed as registers to the asm code, so that we
+ *     don't have to experience issues with register constraints.
+ *
+ * Syscalls for MIPS ABI N32, same as ABI O32 with the following differences :
+ *   - arguments are in a0, a1, a2, a3, t0, t1, t2, t3.
+ *     t0..t3 are also known as a4..a7.
+ *   - stack is 16-byte aligned
+ */
+
+#if !defined(__mips_isa_rev) || __mips_isa_rev < 6
+#define _NOLIBC_SYSCALL_CLOBBER_HI_LO "hi", "lo"
+#else
+#define _NOLIBC_SYSCALL_CLOBBER_HI_LO "$0"
+#endif
+
+#if defined(_ABIO32)
+
+#define _NOLIBC_SYSCALL_CLOBBERLIST \
+	"memory", "cc", "at", "v1", \
+	"t0", "t1", "t2", "t3", "t4", "t5", "t6", "t7", "t8", "t9", \
+	_NOLIBC_SYSCALL_CLOBBER_HI_LO
+
+#define _NOLIBC_SYSCALL_STACK_RESERVE "addiu $sp, $sp, -32\n"
+#define _NOLIBC_SYSCALL_STACK_UNRESERVE "addiu $sp, $sp, 32\n"
+
+#define _NOLIBC_SYSCALL_REG register long
+
+#else /* _ABIN32 || _ABI64 */
+
+/* binutils, GCC and clang disagree about register aliases, use numbers instead. */
+#define _NOLIBC_SYSCALL_CLOBBERLIST \
+	"memory", "cc", "at", "v1", \
+	"10", "11", "12", "13", "14", "15", "24", "25", \
+	_NOLIBC_SYSCALL_CLOBBER_HI_LO
+
+#define _NOLIBC_SYSCALL_STACK_RESERVE
+#define _NOLIBC_SYSCALL_STACK_UNRESERVE
+
+#define _NOLIBC_SYSCALL_REG register long long
+
+#endif /* _ABIO32 */
+
+#define __nolibc_syscall0(num)                                                \
+({                                                                            \
+	_NOLIBC_SYSCALL_REG _num __asm__ ("v0")  = (num);                     \
+	_NOLIBC_SYSCALL_REG _arg4 __asm__ ("a3");                             \
+									      \
+	__asm__ volatile (                                                    \
+		_NOLIBC_SYSCALL_STACK_RESERVE                                 \
+		"syscall\n"                                                   \
+		_NOLIBC_SYSCALL_STACK_UNRESERVE                               \
+		: "=r"(_num), "=r"(_arg4)                                     \
+		: "r"(_num)                                                   \
+		: _NOLIBC_SYSCALL_CLOBBERLIST                                 \
+	);                                                                    \
+	_arg4 ? -_num : _num;                                                 \
+})
+
+#define __nolibc_syscall1(num, arg1)                                          \
+({                                                                            \
+	_NOLIBC_SYSCALL_REG _num __asm__ ("v0")  = (num);                     \
+	_NOLIBC_SYSCALL_REG _arg1 __asm__ ("a0") = __nolibc_arg_to_reg(arg1); \
+	_NOLIBC_SYSCALL_REG _arg4 __asm__ ("a3");                             \
+									      \
+	__asm__ volatile (                                                    \
+		_NOLIBC_SYSCALL_STACK_RESERVE                                 \
+		"syscall\n"                                                   \
+		_NOLIBC_SYSCALL_STACK_UNRESERVE                               \
+		: "=r"(_num), "=r"(_arg4)                                     \
+		: "0"(_num),                                                  \
+		  "r"(_arg1)                                                  \
+		: _NOLIBC_SYSCALL_CLOBBERLIST                                 \
+	);                                                                    \
+	_arg4 ? -_num : _num;                                                 \
+})
+
+#define __nolibc_syscall2(num, arg1, arg2)                                    \
+({                                                                            \
+	_NOLIBC_SYSCALL_REG _num __asm__ ("v0")  = (num);                     \
+	_NOLIBC_SYSCALL_REG _arg1 __asm__ ("a0") = __nolibc_arg_to_reg(arg1); \
+	_NOLIBC_SYSCALL_REG _arg2 __asm__ ("a1") = __nolibc_arg_to_reg(arg2); \
+	_NOLIBC_SYSCALL_REG _arg4 __asm__ ("a3");                             \
+									      \
+	__asm__ volatile (                                                    \
+		_NOLIBC_SYSCALL_STACK_RESERVE                                 \
+		"syscall\n"                                                   \
+		_NOLIBC_SYSCALL_STACK_UNRESERVE                               \
+		: "=r"(_num), "=r"(_arg4)                                     \
+		: "0"(_num),                                                  \
+		  "r"(_arg1), "r"(_arg2)                                      \
+		: _NOLIBC_SYSCALL_CLOBBERLIST                                 \
+	);                                                                    \
+	_arg4 ? -_num : _num;                                                 \
+})
+
+#define __nolibc_syscall3(num, arg1, arg2, arg3)                              \
+({                                                                            \
+	_NOLIBC_SYSCALL_REG _num __asm__ ("v0")  = (num);                     \
+	_NOLIBC_SYSCALL_REG _arg1 __asm__ ("a0") = __nolibc_arg_to_reg(arg1); \
+	_NOLIBC_SYSCALL_REG _arg2 __asm__ ("a1") = __nolibc_arg_to_reg(arg2); \
+	_NOLIBC_SYSCALL_REG _arg3 __asm__ ("a2") = __nolibc_arg_to_reg(arg3); \
+	_NOLIBC_SYSCALL_REG _arg4 __asm__ ("a3");                             \
+									      \
+	__asm__ volatile (                                                    \
+		_NOLIBC_SYSCALL_STACK_RESERVE                                 \
+		"syscall\n"                                                   \
+		_NOLIBC_SYSCALL_STACK_UNRESERVE                               \
+		: "=r"(_num), "=r"(_arg4)                                     \
+		: "0"(_num),                                                  \
+		  "r"(_arg1), "r"(_arg2), "r"(_arg3)                          \
+		: _NOLIBC_SYSCALL_CLOBBERLIST                                 \
+	);                                                                    \
+	_arg4 ? -_num : _num;                                                 \
+})
+
+#define __nolibc_syscall4(num, arg1, arg2, arg3, arg4)                        \
+({                                                                            \
+	_NOLIBC_SYSCALL_REG _num __asm__ ("v0")  = (num);                     \
+	_NOLIBC_SYSCALL_REG _arg1 __asm__ ("a0") = __nolibc_arg_to_reg(arg1); \
+	_NOLIBC_SYSCALL_REG _arg2 __asm__ ("a1") = __nolibc_arg_to_reg(arg2); \
+	_NOLIBC_SYSCALL_REG _arg3 __asm__ ("a2") = __nolibc_arg_to_reg(arg3); \
+	_NOLIBC_SYSCALL_REG _arg4 __asm__ ("a3") = __nolibc_arg_to_reg(arg4); \
+									      \
+	__asm__ volatile (                                                    \
+		_NOLIBC_SYSCALL_STACK_RESERVE                                 \
+		"syscall\n"                                                   \
+		_NOLIBC_SYSCALL_STACK_UNRESERVE                               \
+		: "=r" (_num), "=r"(_arg4)                                    \
+		: "0"(_num),                                                  \
+		  "r"(_arg1), "r"(_arg2), "r"(_arg3), "r"(_arg4)              \
+		: _NOLIBC_SYSCALL_CLOBBERLIST                                 \
+	);                                                                    \
+	_arg4 ? -_num : _num;                                                 \
+})
+
+#if defined(_ABIO32)
+
+#define __nolibc_syscall5(num, arg1, arg2, arg3, arg4, arg5)                  \
+({                                                                            \
+	_NOLIBC_SYSCALL_REG _num __asm__ ("v0")  = (num);                     \
+	_NOLIBC_SYSCALL_REG _arg1 __asm__ ("a0") = __nolibc_arg_to_reg(arg1); \
+	_NOLIBC_SYSCALL_REG _arg2 __asm__ ("a1") = __nolibc_arg_to_reg(arg2); \
+	_NOLIBC_SYSCALL_REG _arg3 __asm__ ("a2") = __nolibc_arg_to_reg(arg3); \
+	_NOLIBC_SYSCALL_REG _arg4 __asm__ ("a3") = __nolibc_arg_to_reg(arg4); \
+	_NOLIBC_SYSCALL_REG _arg5 = __nolibc_arg_to_reg(arg5);                \
+									      \
+	__asm__ volatile (                                                    \
+		_NOLIBC_SYSCALL_STACK_RESERVE                                 \
+		"sw %7, 16($sp)\n"                                            \
+		"syscall\n"                                                   \
+		_NOLIBC_SYSCALL_STACK_UNRESERVE                               \
+		: "=r" (_num), "=r"(_arg4)                                    \
+		: "0"(_num),                                                  \
+		  "r"(_arg1), "r"(_arg2), "r"(_arg3), "r"(_arg4), "r"(_arg5)  \
+		: _NOLIBC_SYSCALL_CLOBBERLIST                                 \
+	);                                                                    \
+	_arg4 ? -_num : _num;                                                 \
+})
+
+#define __nolibc_syscall6(num, arg1, arg2, arg3, arg4, arg5, arg6)            \
+({                                                                            \
+	_NOLIBC_SYSCALL_REG _num __asm__ ("v0")  = (num);                     \
+	_NOLIBC_SYSCALL_REG _arg1 __asm__ ("a0") = __nolibc_arg_to_reg(arg1); \
+	_NOLIBC_SYSCALL_REG _arg2 __asm__ ("a1") = __nolibc_arg_to_reg(arg2); \
+	_NOLIBC_SYSCALL_REG _arg3 __asm__ ("a2") = __nolibc_arg_to_reg(arg3); \
+	_NOLIBC_SYSCALL_REG _arg4 __asm__ ("a3") = __nolibc_arg_to_reg(arg4); \
+	_NOLIBC_SYSCALL_REG _arg5 = __nolibc_arg_to_reg(arg5);                \
+	_NOLIBC_SYSCALL_REG _arg6 = __nolibc_arg_to_reg(arg6);                \
+									      \
+	__asm__ volatile (                                                    \
+		_NOLIBC_SYSCALL_STACK_RESERVE                                 \
+		"sw %7, 16($sp)\n"                                            \
+		"sw %8, 20($sp)\n"                                            \
+		"syscall\n"                                                   \
+		_NOLIBC_SYSCALL_STACK_UNRESERVE                               \
+		: "=r" (_num), "=r"(_arg4)                                    \
+		: "0"(_num),                                                  \
+		  "r"(_arg1), "r"(_arg2), "r"(_arg3), "r"(_arg4), "r"(_arg5), \
+		  "r"(_arg6)                                                  \
+		: _NOLIBC_SYSCALL_CLOBBERLIST                                 \
+	);                                                                    \
+	_arg4 ? -_num : _num;                                                 \
+})
+
+#else /* _ABIN32 || _ABI64 */
+
+#define __nolibc_syscall5(num, arg1, arg2, arg3, arg4, arg5)                  \
+({                                                                            \
+	_NOLIBC_SYSCALL_REG _num __asm__ ("v0")  = (num);                     \
+	_NOLIBC_SYSCALL_REG _arg1 __asm__ ("$4") = __nolibc_arg_to_reg(arg1); \
+	_NOLIBC_SYSCALL_REG _arg2 __asm__ ("$5") = __nolibc_arg_to_reg(arg2); \
+	_NOLIBC_SYSCALL_REG _arg3 __asm__ ("$6") = __nolibc_arg_to_reg(arg3); \
+	_NOLIBC_SYSCALL_REG _arg4 __asm__ ("$7") = __nolibc_arg_to_reg(arg4); \
+	_NOLIBC_SYSCALL_REG _arg5 __asm__ ("$8") = __nolibc_arg_to_reg(arg5); \
+									      \
+	__asm__ volatile (                                                    \
+		"syscall\n"                                                   \
+		: "=r" (_num), "=r"(_arg4)                                    \
+		: "0"(_num),                                                  \
+		  "r"(_arg1), "r"(_arg2), "r"(_arg3), "r"(_arg4), "r"(_arg5)  \
+		: _NOLIBC_SYSCALL_CLOBBERLIST                                 \
+	);                                                                    \
+	_arg4 ? -_num : _num;                                                 \
+})
+
+#define __nolibc_syscall6(num, arg1, arg2, arg3, arg4, arg5, arg6)            \
+({                                                                            \
+	_NOLIBC_SYSCALL_REG _num __asm__ ("v0")  = (num);                     \
+	_NOLIBC_SYSCALL_REG _arg1 __asm__ ("$4") = __nolibc_arg_to_reg(arg1); \
+	_NOLIBC_SYSCALL_REG _arg2 __asm__ ("$5") = __nolibc_arg_to_reg(arg2); \
+	_NOLIBC_SYSCALL_REG _arg3 __asm__ ("$6") = __nolibc_arg_to_reg(arg3); \
+	_NOLIBC_SYSCALL_REG _arg4 __asm__ ("$7") = __nolibc_arg_to_reg(arg4); \
+	_NOLIBC_SYSCALL_REG _arg5 __asm__ ("$8") = __nolibc_arg_to_reg(arg5); \
+	_NOLIBC_SYSCALL_REG _arg6 __asm__ ("$9") = __nolibc_arg_to_reg(arg6); \
+									      \
+	__asm__ volatile (                                                    \
+		"syscall\n"                                                   \
+		: "=r" (_num), "=r"(_arg4)                                    \
+		: "0"(_num),                                                  \
+		  "r"(_arg1), "r"(_arg2), "r"(_arg3), "r"(_arg4), "r"(_arg5), \
+		  "r"(_arg6)                                                  \
+		: _NOLIBC_SYSCALL_CLOBBERLIST                                 \
+	);                                                                    \
+	_arg4 ? -_num : _num;                                                 \
+})
+
+#endif /* _ABIO32 */
+
+#ifndef NOLIBC_NO_RUNTIME
+/* startup code, note that it's called __start on MIPS */
+void __start(void);
+void __attribute__((weak, noreturn)) __nolibc_entrypoint __nolibc_no_stack_protector __start(void)
+{
+	__asm__ volatile (
+		"move  $a0, $sp\n"       /* save stack pointer to $a0, as arg1 of _start_c */
+#if defined(_ABIO32)
+		"addiu $sp, $sp, -16\n"  /* the callee expects to save a0..a3 there        */
+#endif /* _ABIO32 */
+		"lui $t9, %hi(_start_c)\n" /* ABI requires current function address in $t9 */
+		"ori $t9, %lo(_start_c)\n"
+#if defined(_ABI64)
+		"lui  $t0, %highest(_start_c)\n"
+		"ori  $t0, %higher(_start_c)\n"
+		"dsll $t0, 0x20\n"
+		"or   $t9, $t0\n"
+#endif /* _ABI64 */
+		"jalr $t9\n"             /* transfer to c runtime                          */
+	);
+	__nolibc_entrypoint_epilogue();
+}
+#endif /* NOLIBC_NO_RUNTIME */
+
+#if defined(_ABIO32)
+static __attribute__((unused))
+int _sys_ftruncate64(int fd, uint32_t length0, uint32_t length1)
+{
+	return __nolibc_syscall4(__NR_ftruncate64, fd, 0, length0, length1);
+}
+#define _sys_ftruncate64 _sys_ftruncate64
+#endif
+
+#endif /* _NOLIBC_ARCH_MIPS_H */