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, 129 insertions, 0 deletions

diff --git a/tools/perf/util/lzma.c b/tools/perf/util/lzma.c
new file mode 100644
index 000000000..91b9b5171
--- /dev/null
+++ b/tools/perf/util/lzma.c
@@ -0,0 +1,129 @@
+// SPDX-License-Identifier: GPL-2.0
+#include <errno.h>
+#include <lzma.h>
+#include <stdio.h>
+#include <linux/compiler.h>
+#include <sys/types.h>
+#include <sys/stat.h>
+#include <fcntl.h>
+#include "compress.h"
+#include "debug.h"
+#include <string.h>
+#include <unistd.h>
+#include <internal/lib.h>
+
+#define BUFSIZE 8192
+
+static const char *lzma_strerror(lzma_ret ret)
+{
+	switch ((int) ret) {
+	case LZMA_MEM_ERROR:
+		return "Memory allocation failed";
+	case LZMA_OPTIONS_ERROR:
+		return "Unsupported decompressor flags";
+	case LZMA_FORMAT_ERROR:
+		return "The input is not in the .xz format";
+	case LZMA_DATA_ERROR:
+		return "Compressed file is corrupt";
+	case LZMA_BUF_ERROR:
+		return "Compressed file is truncated or otherwise corrupt";
+	default:
+		return "Unknown error, possibly a bug";
+	}
+}
+
+int lzma_decompress_stream_to_file(FILE *infile, int output_fd)
+{
+	lzma_action action = LZMA_RUN;
+	lzma_stream strm   = LZMA_STREAM_INIT;
+	lzma_ret ret;
+	int err = -1;
+
+	u8 buf_in[BUFSIZE];
+	u8 buf_out[BUFSIZE];
+
+	ret = lzma_stream_decoder(&strm, UINT64_MAX, LZMA_CONCATENATED);
+	if (ret != LZMA_OK) {
+		pr_debug("lzma: lzma_stream_decoder failed %s (%d)\n", lzma_strerror(ret), ret);
+		return err;
+	}
+
+	strm.next_in   = NULL;
+	strm.avail_in  = 0;
+	strm.next_out  = buf_out;
+	strm.avail_out = sizeof(buf_out);
+
+	while (1) {
+		if (strm.avail_in == 0 && !feof(infile)) {
+			strm.next_in  = buf_in;
+			strm.avail_in = fread(buf_in, 1, sizeof(buf_in), infile);
+
+			if (ferror(infile)) {
+				pr_debug("lzma: read error: %m\n");
+				goto err_lzma_end;
+			}
+
+			if (feof(infile))
+				action = LZMA_FINISH;
+		}
+
+		ret = lzma_code(&strm, action);
+
+		if (strm.avail_out == 0 || ret == LZMA_STREAM_END) {
+			ssize_t write_size = sizeof(buf_out) - strm.avail_out;
+
+			if (writen(output_fd, buf_out, write_size) != write_size) {
+				pr_debug("lzma: write error: %m\n");
+				goto err_lzma_end;
+			}
+
+			strm.next_out  = buf_out;
+			strm.avail_out = sizeof(buf_out);
+		}
+
+		if (ret != LZMA_OK) {
+			if (ret == LZMA_STREAM_END)
+				break;
+
+			pr_debug("lzma: failed %s\n", lzma_strerror(ret));
+			goto err_lzma_end;
+		}
+	}
+
+	err = 0;
+err_lzma_end:
+	lzma_end(&strm);
+	return err;
+}
+
+int lzma_decompress_to_file(const char *input, int output_fd)
+{
+	FILE *infile;
+	int ret;
+
+	infile = fopen(input, "rb");
+	if (!infile) {
+		pr_debug("lzma: fopen failed on %s: '%m'\n", input);
+		return -1;
+	}
+
+	ret = lzma_decompress_stream_to_file(infile, output_fd);
+	fclose(infile);
+	return ret;
+}
+
+bool lzma_is_compressed(const char *input)
+{
+	int fd = open(input, O_RDONLY);
+	const uint8_t magic[6] = { 0xFD, '7', 'z', 'X', 'Z', 0x00 };
+	char buf[6] = { 0 };
+	ssize_t rc;
+
+	if (fd < 0)
+		return false;
+
+	rc = read(fd, buf, sizeof(buf));
+	close(fd);
+	return rc == sizeof(buf) ?
+	       memcmp(buf, magic, sizeof(buf)) == 0 : false;
+}