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, 47 insertions, 0 deletions

diff --git a/tools/perf/util/symsrc.h b/tools/perf/util/symsrc.h
new file mode 100644
index 000000000..edf82028c
--- /dev/null
+++ b/tools/perf/util/symsrc.h
@@ -0,0 +1,47 @@
+/* SPDX-License-Identifier: GPL-2.0 */
+#ifndef __PERF_SYMSRC_
+#define __PERF_SYMSRC_ 1
+
+#include <stdbool.h>
+#include <stddef.h>
+#include "dso.h"
+
+#ifdef HAVE_LIBELF_SUPPORT
+#include <libelf.h>
+#include <gelf.h>
+#endif
+#include <elf.h>
+
+struct symsrc {
+	char		     *name;
+	int		     fd;
+	enum dso_binary_type type;
+
+#ifdef HAVE_LIBELF_SUPPORT
+	Elf		     *elf;
+	GElf_Ehdr	     ehdr;
+
+	Elf_Scn		     *opdsec;
+	size_t		     opdidx;
+	GElf_Shdr	     opdshdr;
+
+	Elf_Scn		     *symtab;
+	size_t		     symtab_idx;
+	GElf_Shdr	     symshdr;
+
+	Elf_Scn		     *dynsym;
+	size_t		     dynsym_idx;
+	GElf_Shdr	     dynshdr;
+
+	bool		     adjust_symbols;
+	bool		     is_64_bit;
+#endif
+};
+
+int symsrc__init(struct symsrc *ss, struct dso *dso, const char *name, enum dso_binary_type type);
+void symsrc__destroy(struct symsrc *ss);
+
+bool symsrc__has_symtab(struct symsrc *ss);
+bool symsrc__possibly_runtime(struct symsrc *ss);
+
+#endif /* __PERF_SYMSRC_ */