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, 305 insertions, 0 deletions

diff --git a/scripts/elf-parse.h b/scripts/elf-parse.h
new file mode 100644
index 000000000..f4411e030
--- /dev/null
+++ b/scripts/elf-parse.h
@@ -0,0 +1,305 @@
+/* SPDX-License-Identifier: GPL-2.0-only */
+#ifndef _SCRIPTS_ELF_PARSE_H
+#define _SCRIPTS_ELF_PARSE_H
+
+#include <elf.h>
+
+#include <tools/be_byteshift.h>
+#include <tools/le_byteshift.h>
+
+typedef union {
+	Elf32_Ehdr	e32;
+	Elf64_Ehdr	e64;
+} Elf_Ehdr;
+
+typedef union {
+	Elf32_Shdr	e32;
+	Elf64_Shdr	e64;
+} Elf_Shdr;
+
+typedef union {
+	Elf32_Sym	e32;
+	Elf64_Sym	e64;
+} Elf_Sym;
+
+typedef union {
+	Elf32_Rela	e32;
+	Elf64_Rela	e64;
+} Elf_Rela;
+
+struct elf_funcs {
+	int (*compare_extable)(const void *a, const void *b);
+	uint64_t (*ehdr_shoff)(Elf_Ehdr *ehdr);
+	uint16_t (*ehdr_shstrndx)(Elf_Ehdr *ehdr);
+	uint16_t (*ehdr_shentsize)(Elf_Ehdr *ehdr);
+	uint16_t (*ehdr_shnum)(Elf_Ehdr *ehdr);
+	uint64_t (*shdr_addr)(Elf_Shdr *shdr);
+	uint64_t (*shdr_offset)(Elf_Shdr *shdr);
+	uint64_t (*shdr_size)(Elf_Shdr *shdr);
+	uint64_t (*shdr_entsize)(Elf_Shdr *shdr);
+	uint32_t (*shdr_link)(Elf_Shdr *shdr);
+	uint32_t (*shdr_name)(Elf_Shdr *shdr);
+	uint32_t (*shdr_type)(Elf_Shdr *shdr);
+	uint8_t (*sym_type)(Elf_Sym *sym);
+	uint32_t (*sym_name)(Elf_Sym *sym);
+	uint64_t (*sym_value)(Elf_Sym *sym);
+	uint16_t (*sym_shndx)(Elf_Sym *sym);
+	uint64_t (*rela_offset)(Elf_Rela *rela);
+	uint64_t (*rela_info)(Elf_Rela *rela);
+	uint64_t (*rela_addend)(Elf_Rela *rela);
+	void (*rela_write_addend)(Elf_Rela *rela, uint64_t val);
+	uint32_t (*r)(const uint32_t *);
+	uint16_t (*r2)(const uint16_t *);
+	uint64_t (*r8)(const uint64_t *);
+	void (*w)(uint32_t, uint32_t *);
+	void (*w8)(uint64_t, uint64_t *);
+};
+
+extern struct elf_funcs elf_parser;
+
+static inline uint64_t ehdr64_shoff(Elf_Ehdr *ehdr)
+{
+	return elf_parser.r8(&ehdr->e64.e_shoff);
+}
+
+static inline uint64_t ehdr32_shoff(Elf_Ehdr *ehdr)
+{
+	return elf_parser.r(&ehdr->e32.e_shoff);
+}
+
+static inline uint64_t ehdr_shoff(Elf_Ehdr *ehdr)
+{
+	return elf_parser.ehdr_shoff(ehdr);
+}
+
+#define EHDR_HALF(fn_name)				\
+static inline uint16_t ehdr64_##fn_name(Elf_Ehdr *ehdr)	\
+{							\
+	return elf_parser.r2(&ehdr->e64.e_##fn_name);	\
+}							\
+							\
+static inline uint16_t ehdr32_##fn_name(Elf_Ehdr *ehdr)	\
+{							\
+	return elf_parser.r2(&ehdr->e32.e_##fn_name);	\
+}							\
+							\
+static inline uint16_t ehdr_##fn_name(Elf_Ehdr *ehdr)	\
+{							\
+	return elf_parser.ehdr_##fn_name(ehdr);		\
+}
+
+EHDR_HALF(shentsize)
+EHDR_HALF(shstrndx)
+EHDR_HALF(shnum)
+
+#define SHDR_WORD(fn_name)				\
+static inline uint32_t shdr64_##fn_name(Elf_Shdr *shdr)	\
+{							\
+	return elf_parser.r(&shdr->e64.sh_##fn_name);	\
+}							\
+							\
+static inline uint32_t shdr32_##fn_name(Elf_Shdr *shdr)	\
+{							\
+	return elf_parser.r(&shdr->e32.sh_##fn_name);	\
+}							\
+							\
+static inline uint32_t shdr_##fn_name(Elf_Shdr *shdr)	\
+{							\
+	return elf_parser.shdr_##fn_name(shdr);	\
+}
+
+#define SHDR_ADDR(fn_name)				\
+static inline uint64_t shdr64_##fn_name(Elf_Shdr *shdr)	\
+{							\
+	return elf_parser.r8(&shdr->e64.sh_##fn_name);	\
+}							\
+							\
+static inline uint64_t shdr32_##fn_name(Elf_Shdr *shdr)	\
+{							\
+	return elf_parser.r(&shdr->e32.sh_##fn_name);	\
+}							\
+							\
+static inline uint64_t shdr_##fn_name(Elf_Shdr *shdr)	\
+{							\
+	return elf_parser.shdr_##fn_name(shdr);		\
+}
+
+#define SHDR_WORD(fn_name)				\
+static inline uint32_t shdr64_##fn_name(Elf_Shdr *shdr)	\
+{							\
+	return elf_parser.r(&shdr->e64.sh_##fn_name);	\
+}							\
+							\
+static inline uint32_t shdr32_##fn_name(Elf_Shdr *shdr)	\
+{							\
+	return elf_parser.r(&shdr->e32.sh_##fn_name);	\
+}							\
+static inline uint32_t shdr_##fn_name(Elf_Shdr *shdr)	\
+{							\
+	return elf_parser.shdr_##fn_name(shdr);		\
+}
+
+SHDR_ADDR(addr)
+SHDR_ADDR(offset)
+SHDR_ADDR(size)
+SHDR_ADDR(entsize)
+
+SHDR_WORD(link)
+SHDR_WORD(name)
+SHDR_WORD(type)
+
+#define SYM_ADDR(fn_name)				\
+static inline uint64_t sym64_##fn_name(Elf_Sym *sym)	\
+{							\
+	return elf_parser.r8(&sym->e64.st_##fn_name);	\
+}							\
+							\
+static inline uint64_t sym32_##fn_name(Elf_Sym *sym)	\
+{							\
+	return elf_parser.r(&sym->e32.st_##fn_name);	\
+}							\
+							\
+static inline uint64_t sym_##fn_name(Elf_Sym *sym)	\
+{							\
+	return elf_parser.sym_##fn_name(sym);		\
+}
+
+#define SYM_WORD(fn_name)				\
+static inline uint32_t sym64_##fn_name(Elf_Sym *sym)	\
+{							\
+	return elf_parser.r(&sym->e64.st_##fn_name);	\
+}							\
+							\
+static inline uint32_t sym32_##fn_name(Elf_Sym *sym)	\
+{							\
+	return elf_parser.r(&sym->e32.st_##fn_name);	\
+}							\
+							\
+static inline uint32_t sym_##fn_name(Elf_Sym *sym)	\
+{							\
+	return elf_parser.sym_##fn_name(sym);		\
+}
+
+#define SYM_HALF(fn_name)				\
+static inline uint16_t sym64_##fn_name(Elf_Sym *sym)	\
+{							\
+	return elf_parser.r2(&sym->e64.st_##fn_name);	\
+}							\
+							\
+static inline uint16_t sym32_##fn_name(Elf_Sym *sym)	\
+{							\
+	return elf_parser.r2(&sym->e32.st_##fn_name);	\
+}							\
+							\
+static inline uint16_t sym_##fn_name(Elf_Sym *sym)	\
+{							\
+	return elf_parser.sym_##fn_name(sym);		\
+}
+
+static inline uint8_t sym64_type(Elf_Sym *sym)
+{
+	return ELF64_ST_TYPE(sym->e64.st_info);
+}
+
+static inline uint8_t sym32_type(Elf_Sym *sym)
+{
+	return ELF32_ST_TYPE(sym->e32.st_info);
+}
+
+static inline uint8_t sym_type(Elf_Sym *sym)
+{
+	return elf_parser.sym_type(sym);
+}
+
+SYM_ADDR(value)
+SYM_WORD(name)
+SYM_HALF(shndx)
+
+#define __maybe_unused			__attribute__((__unused__))
+
+#define RELA_ADDR(fn_name)						\
+static inline uint64_t rela64_##fn_name(Elf_Rela *rela)			\
+{									\
+	return elf_parser.r8((uint64_t *)&rela->e64.r_##fn_name);	\
+}									\
+									\
+static inline uint64_t rela32_##fn_name(Elf_Rela *rela)			\
+{									\
+	return elf_parser.r((uint32_t *)&rela->e32.r_##fn_name);	\
+}									\
+									\
+static inline uint64_t __maybe_unused rela_##fn_name(Elf_Rela *rela)	\
+{									\
+	return elf_parser.rela_##fn_name(rela);				\
+}
+
+RELA_ADDR(offset)
+RELA_ADDR(info)
+RELA_ADDR(addend)
+
+static inline void rela64_write_addend(Elf_Rela *rela, uint64_t val)
+{
+	elf_parser.w8(val, (uint64_t *)&rela->e64.r_addend);
+}
+
+static inline void rela32_write_addend(Elf_Rela *rela, uint64_t val)
+{
+	elf_parser.w(val, (uint32_t *)&rela->e32.r_addend);
+}
+
+static inline uint32_t rbe(const uint32_t *x)
+{
+	return get_unaligned_be32(x);
+}
+
+static inline uint16_t r2be(const uint16_t *x)
+{
+	return get_unaligned_be16(x);
+}
+
+static inline uint64_t r8be(const uint64_t *x)
+{
+	return get_unaligned_be64(x);
+}
+
+static inline uint32_t rle(const uint32_t *x)
+{
+	return get_unaligned_le32(x);
+}
+
+static inline uint16_t r2le(const uint16_t *x)
+{
+	return get_unaligned_le16(x);
+}
+
+static inline uint64_t r8le(const uint64_t *x)
+{
+	return get_unaligned_le64(x);
+}
+
+static inline void wbe(uint32_t val, uint32_t *x)
+{
+	put_unaligned_be32(val, x);
+}
+
+static inline void wle(uint32_t val, uint32_t *x)
+{
+	put_unaligned_le32(val, x);
+}
+
+static inline void w8be(uint64_t val, uint64_t *x)
+{
+	put_unaligned_be64(val, x);
+}
+
+static inline void w8le(uint64_t val, uint64_t *x)
+{
+	put_unaligned_le64(val, x);
+}
+
+void *elf_map(char const *fname, size_t *size, uint32_t types);
+void elf_unmap(void *addr, size_t size);
+int elf_map_machine(void *addr);
+int elf_map_long_size(void *addr);
+
+#endif /* _SCRIPTS_ELF_PARSE_H */