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, 163 insertions, 0 deletions

diff --git a/lib/ubsan.h b/lib/ubsan.h
new file mode 100644
index 000000000..b37e22374
--- /dev/null
+++ b/lib/ubsan.h
@@ -0,0 +1,163 @@
+/* SPDX-License-Identifier: GPL-2.0 */
+#ifndef _LIB_UBSAN_H
+#define _LIB_UBSAN_H
+
+/*
+ * ABI defined by Clang's UBSAN enum SanitizerHandler:
+ * https://github.com/llvm/llvm-project/blob/release/16.x/clang/lib/CodeGen/CodeGenFunction.h#L113
+ */
+enum ubsan_checks {
+	ubsan_add_overflow,
+	ubsan_builtin_unreachable,
+	ubsan_cfi_check_fail,
+	ubsan_divrem_overflow,
+	ubsan_dynamic_type_cache_miss,
+	ubsan_float_cast_overflow,
+	ubsan_function_type_mismatch,
+	ubsan_implicit_conversion,
+	ubsan_invalid_builtin,
+	ubsan_invalid_objc_cast,
+	ubsan_load_invalid_value,
+	ubsan_missing_return,
+	ubsan_mul_overflow,
+	ubsan_negate_overflow,
+	ubsan_nullability_arg,
+	ubsan_nullability_return,
+	ubsan_nonnull_arg,
+	ubsan_nonnull_return,
+	ubsan_out_of_bounds,
+	ubsan_pointer_overflow,
+	ubsan_shift_out_of_bounds,
+	ubsan_sub_overflow,
+	ubsan_type_mismatch,
+	ubsan_alignment_assumption,
+	ubsan_vla_bound_not_positive,
+};
+
+enum {
+	type_kind_int = 0,
+	type_kind_float = 1,
+	type_unknown = 0xffff
+};
+
+struct type_descriptor {
+	u16 type_kind;
+	u16 type_info;
+	char type_name[];
+};
+
+struct source_location {
+	const char *file_name;
+	union {
+		unsigned long reported;
+		struct {
+			u32 line;
+			u32 column;
+		};
+	};
+};
+
+struct overflow_data {
+	struct source_location location;
+	struct type_descriptor *type;
+};
+
+struct implicit_conversion_data {
+	struct source_location location;
+	struct type_descriptor *from_type;
+	struct type_descriptor *to_type;
+	unsigned char type_check_kind;
+};
+
+struct type_mismatch_data {
+	struct source_location location;
+	struct type_descriptor *type;
+	unsigned long alignment;
+	unsigned char type_check_kind;
+};
+
+struct type_mismatch_data_v1 {
+	struct source_location location;
+	struct type_descriptor *type;
+	unsigned char log_alignment;
+	unsigned char type_check_kind;
+};
+
+struct type_mismatch_data_common {
+	struct source_location *location;
+	struct type_descriptor *type;
+	unsigned long alignment;
+	unsigned char type_check_kind;
+};
+
+struct nonnull_arg_data {
+	struct source_location location;
+	struct source_location attr_location;
+	int arg_index;
+};
+
+struct out_of_bounds_data {
+	struct source_location location;
+	struct type_descriptor *array_type;
+	struct type_descriptor *index_type;
+};
+
+struct shift_out_of_bounds_data {
+	struct source_location location;
+	struct type_descriptor *lhs_type;
+	struct type_descriptor *rhs_type;
+};
+
+struct unreachable_data {
+	struct source_location location;
+};
+
+struct invalid_value_data {
+	struct source_location location;
+	struct type_descriptor *type;
+};
+
+struct alignment_assumption_data {
+	struct source_location location;
+	struct source_location assumption_location;
+	struct type_descriptor *type;
+};
+
+#if defined(CONFIG_ARCH_SUPPORTS_INT128)
+typedef __int128 s_max;
+typedef unsigned __int128 u_max;
+#else
+typedef s64 s_max;
+typedef u64 u_max;
+#endif
+
+/*
+ * When generating Runtime Calls, Clang doesn't respect the -mregparm=3
+ * option used on i386: https://github.com/llvm/llvm-project/issues/89670
+ * Fix this for earlier Clang versions by forcing the calling convention
+ * to use non-register arguments.
+ */
+#if defined(CONFIG_X86_32) && \
+    defined(CONFIG_CC_IS_CLANG) && CONFIG_CLANG_VERSION < 190000
+# define ubsan_linkage asmlinkage
+#else
+# define ubsan_linkage
+#endif
+
+void ubsan_linkage __ubsan_handle_add_overflow(void *data, void *lhs, void *rhs);
+void ubsan_linkage __ubsan_handle_sub_overflow(void *data, void *lhs, void *rhs);
+void ubsan_linkage __ubsan_handle_mul_overflow(void *data, void *lhs, void *rhs);
+void ubsan_linkage __ubsan_handle_negate_overflow(void *_data, void *old_val);
+void ubsan_linkage __ubsan_handle_divrem_overflow(void *_data, void *lhs, void *rhs);
+void ubsan_linkage __ubsan_handle_implicit_conversion(void *_data, void *lhs, void *rhs);
+void ubsan_linkage __ubsan_handle_type_mismatch(struct type_mismatch_data *data, void *ptr);
+void ubsan_linkage __ubsan_handle_type_mismatch_v1(void *_data, void *ptr);
+void ubsan_linkage __ubsan_handle_out_of_bounds(void *_data, void *index);
+void ubsan_linkage __ubsan_handle_shift_out_of_bounds(void *_data, void *lhs, void *rhs);
+void ubsan_linkage __ubsan_handle_builtin_unreachable(void *_data);
+void ubsan_linkage __ubsan_handle_load_invalid_value(void *_data, void *val);
+void ubsan_linkage __ubsan_handle_alignment_assumption(void *_data, unsigned long ptr,
+						       unsigned long align,
+						       unsigned long offset);
+
+#endif