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, 66 insertions, 0 deletions

diff --git a/tools/perf/util/top.h b/tools/perf/util/top.h
new file mode 100644
index 000000000..04ff92684
--- /dev/null
+++ b/tools/perf/util/top.h
@@ -0,0 +1,66 @@
+/* SPDX-License-Identifier: GPL-2.0 */
+#ifndef __PERF_TOP_H
+#define __PERF_TOP_H 1
+
+#include "tool.h"
+#include "evswitch.h"
+#include "annotate.h"
+#include "mutex.h"
+#include "ordered-events.h"
+#include "record.h"
+#include <linux/types.h>
+#include <stddef.h>
+#include <stdbool.h>
+#include <sys/ioctl.h>
+
+struct evlist;
+struct evsel;
+struct perf_session;
+
+struct perf_top {
+	struct perf_tool   tool;
+	struct evlist *evlist, *sb_evlist;
+	struct record_opts record_opts;
+	struct evswitch	   evswitch;
+	/*
+	 * Symbols will be added here in perf_event__process_sample and will
+	 * get out after decayed.
+	 */
+	u64		   samples, lost, lost_total, drop, drop_total;
+	u64		   kernel_samples, us_samples;
+	u64		   exact_samples;
+	u64		   guest_us_samples, guest_kernel_samples;
+	int		   print_entries, count_filter, delay_secs;
+	int		   max_stack;
+	bool		   hide_kernel_symbols, hide_user_symbols, zero;
+#ifdef HAVE_SLANG_SUPPORT
+	bool		   use_tui;
+#endif
+	bool		   use_stdio;
+	bool		   vmlinux_warned;
+	bool		   dump_symtab;
+	bool		   stitch_lbr;
+	struct hist_entry  *sym_filter_entry;
+	struct evsel 	   *sym_evsel;
+	struct perf_session *session;
+	struct winsize	   winsize;
+	int		   realtime_prio;
+	const char	   *sym_filter;
+	float		   min_percent;
+	unsigned int	   nr_threads_synthesize;
+	const char	   *uid_str;
+
+	struct {
+		struct ordered_events	*in;
+		struct ordered_events	 data[2];
+		bool			 rotate;
+		struct mutex mutex;
+		struct cond cond;
+	} qe;
+};
+
+#define CONSOLE_CLEAR ""
+
+size_t perf_top__header_snprintf(struct perf_top *top, char *bf, size_t size);
+void perf_top__reset_sample_counters(struct perf_top *top);
+#endif /* __PERF_TOP_H */