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, 89 insertions, 0 deletions

diff --git a/tools/perf/util/genelf.h b/tools/perf/util/genelf.h
new file mode 100644
index 000000000..9f0b875d6
--- /dev/null
+++ b/tools/perf/util/genelf.h
@@ -0,0 +1,89 @@
+/* SPDX-License-Identifier: GPL-2.0 */
+#ifndef __GENELF_H__
+#define __GENELF_H__
+
+#include <linux/math.h>
+
+/* genelf.c */
+int jit_write_elf(int fd, uint64_t code_addr, const char *sym,
+		  const void *code, int csize, void *debug, int nr_debug_entries,
+		  void *unwinding, uint64_t unwinding_header_size, uint64_t unwinding_size);
+#ifdef HAVE_LIBDW_SUPPORT
+/* genelf_debug.c */
+int jit_add_debug_info(Elf *e, uint64_t code_addr, void *debug, int nr_debug_entries);
+#endif
+
+#if   defined(__arm__)
+#define GEN_ELF_ARCH	EM_ARM
+#define GEN_ELF_CLASS	ELFCLASS32
+#elif defined(__aarch64__)
+#define GEN_ELF_ARCH	EM_AARCH64
+#define GEN_ELF_CLASS	ELFCLASS64
+#elif defined(__x86_64__)
+#define GEN_ELF_ARCH	EM_X86_64
+#define GEN_ELF_CLASS	ELFCLASS64
+#elif defined(__i386__)
+#define GEN_ELF_ARCH	EM_386
+#define GEN_ELF_CLASS	ELFCLASS32
+#elif defined(__powerpc64__)
+#define GEN_ELF_ARCH	EM_PPC64
+#define GEN_ELF_CLASS	ELFCLASS64
+#elif defined(__powerpc__)
+#define GEN_ELF_ARCH	EM_PPC
+#define GEN_ELF_CLASS	ELFCLASS32
+#elif defined(__sparc__) && defined(__arch64__)
+#define GEN_ELF_ARCH	EM_SPARCV9
+#define GEN_ELF_CLASS	ELFCLASS64
+#elif defined(__sparc__)
+#define GEN_ELF_ARCH	EM_SPARC
+#define GEN_ELF_CLASS	ELFCLASS32
+#elif defined(__s390x__)
+#define GEN_ELF_ARCH	EM_S390
+#define GEN_ELF_CLASS	ELFCLASS64
+#elif defined(__riscv) && __riscv_xlen == 64
+#define GEN_ELF_ARCH	EM_RISCV
+#define GEN_ELF_CLASS	ELFCLASS64
+#elif defined(__riscv) && __riscv_xlen == 32
+#define GEN_ELF_ARCH	EM_RISCV
+#define GEN_ELF_CLASS	ELFCLASS32
+#elif defined(__loongarch__)
+#define GEN_ELF_ARCH	EM_LOONGARCH
+#define GEN_ELF_CLASS	ELFCLASS64
+#else
+#error "unsupported architecture"
+#endif
+
+#if __BYTE_ORDER__ == __ORDER_BIG_ENDIAN__
+#define GEN_ELF_ENDIAN	ELFDATA2MSB
+#else
+#define GEN_ELF_ENDIAN	ELFDATA2LSB
+#endif
+
+#if GEN_ELF_CLASS == ELFCLASS64
+#define elf_newehdr	elf64_newehdr
+#define elf_newphdr	elf64_newphdr
+#define elf_getshdr	elf64_getshdr
+#define Elf_Ehdr	Elf64_Ehdr
+#define Elf_Phdr	Elf64_Phdr
+#define Elf_Shdr	Elf64_Shdr
+#define Elf_Sym		Elf64_Sym
+#define ELF_ST_TYPE(a)	ELF64_ST_TYPE(a)
+#define ELF_ST_BIND(a)	ELF64_ST_BIND(a)
+#define ELF_ST_VIS(a)	ELF64_ST_VISIBILITY(a)
+#else
+#define elf_newehdr	elf32_newehdr
+#define elf_newphdr	elf32_newphdr
+#define elf_getshdr	elf32_getshdr
+#define Elf_Ehdr	Elf32_Ehdr
+#define Elf_Phdr	Elf32_Phdr
+#define Elf_Shdr	Elf32_Shdr
+#define Elf_Sym		Elf32_Sym
+#define ELF_ST_TYPE(a)	ELF32_ST_TYPE(a)
+#define ELF_ST_BIND(a)	ELF32_ST_BIND(a)
+#define ELF_ST_VIS(a)	ELF32_ST_VISIBILITY(a)
+#endif
+
+/* The .text section is directly after the ELF header */
+#define GEN_ELF_TEXT_OFFSET round_up(sizeof(Elf_Ehdr) + sizeof(Elf_Phdr), 16)
+
+#endif