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, 93 insertions, 0 deletions

diff --git a/tools/perf/util/compress.h b/tools/perf/util/compress.h
new file mode 100644
index 000000000..ec6c38129
--- /dev/null
+++ b/tools/perf/util/compress.h
@@ -0,0 +1,93 @@
+/* SPDX-License-Identifier: GPL-2.0 */
+#ifndef PERF_COMPRESS_H
+#define PERF_COMPRESS_H
+
+#include <stdbool.h>
+#include <stddef.h>
+#include <stdio.h>
+#include <sys/types.h>
+#include <linux/compiler.h>
+#ifdef HAVE_ZSTD_SUPPORT
+#include <zstd.h>
+#endif
+
+#ifdef HAVE_ZLIB_SUPPORT
+int gzip_decompress_to_file(const char *input, int output_fd);
+bool gzip_is_compressed(const char *input);
+#endif
+
+#ifdef HAVE_LZMA_SUPPORT
+int lzma_decompress_stream_to_file(FILE *input, int output_fd);
+int lzma_decompress_to_file(const char *input, int output_fd);
+bool lzma_is_compressed(const char *input);
+#else
+static inline
+int lzma_decompress_stream_to_file(FILE *input __maybe_unused,
+				   int output_fd __maybe_unused)
+{
+	return -1;
+}
+static inline
+int lzma_decompress_to_file(const char *input __maybe_unused,
+			    int output_fd __maybe_unused)
+{
+	return -1;
+}
+static inline int lzma_is_compressed(const char *input __maybe_unused)
+{
+	return false;
+}
+#endif
+
+struct zstd_data {
+#ifdef HAVE_ZSTD_SUPPORT
+	ZSTD_CStream	*cstream;
+	ZSTD_DStream	*dstream;
+	int comp_level;
+#endif
+};
+
+#ifdef HAVE_ZSTD_SUPPORT
+
+int zstd_init(struct zstd_data *data, int level);
+int zstd_fini(struct zstd_data *data);
+
+ssize_t zstd_compress_stream_to_records(struct zstd_data *data, void *dst, size_t dst_size,
+				       void *src, size_t src_size, size_t max_record_size,
+				       ssize_t process_header(void *record, size_t dst_size,
+							      size_t data_size));
+
+size_t zstd_decompress_stream(struct zstd_data *data, void *src, size_t src_size,
+			      void *dst, size_t dst_size);
+#else /* !HAVE_ZSTD_SUPPORT */
+
+static inline int zstd_init(struct zstd_data *data __maybe_unused, int level __maybe_unused)
+{
+	return 0;
+}
+
+static inline int zstd_fini(struct zstd_data *data __maybe_unused)
+{
+	return 0;
+}
+
+static inline
+ssize_t zstd_compress_stream_to_records(struct zstd_data *data __maybe_unused,
+				       void *dst __maybe_unused, size_t dst_size __maybe_unused,
+				       void *src __maybe_unused, size_t src_size __maybe_unused,
+				       size_t max_record_size __maybe_unused,
+				       ssize_t process_header(void *record, size_t dst_size,
+							      size_t data_size) __maybe_unused)
+{
+	return 0;
+}
+
+static inline size_t zstd_decompress_stream(struct zstd_data *data __maybe_unused, void *src __maybe_unused,
+					    size_t src_size __maybe_unused, void *dst __maybe_unused,
+					    size_t dst_size __maybe_unused)
+{
+	return 0;
+}
+#endif
+
+#endif /* PERF_COMPRESS_H */