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, 54 insertions, 0 deletions

diff --git a/fs/pstore/internal.h b/fs/pstore/internal.h
new file mode 100644
index 000000000..079284120
--- /dev/null
+++ b/fs/pstore/internal.h
@@ -0,0 +1,54 @@
+/* SPDX-License-Identifier: GPL-2.0 */
+#ifndef __PSTORE_INTERNAL_H__
+#define __PSTORE_INTERNAL_H__
+
+#include <linux/types.h>
+#include <linux/time.h>
+#include <linux/pstore.h>
+
+extern unsigned int kmsg_bytes;
+
+#ifdef CONFIG_PSTORE_FTRACE
+extern unsigned long decode_ip(unsigned long ip);
+extern void pstore_register_ftrace(void);
+extern void pstore_unregister_ftrace(void);
+ssize_t pstore_ftrace_combine_log(char **dest_log, size_t *dest_log_size,
+				  const char *src_log, size_t src_log_size);
+#else
+static inline void pstore_register_ftrace(void) {}
+static inline void pstore_unregister_ftrace(void) {}
+static inline unsigned long decode_ip(unsigned long ip) { return ip; }
+static inline ssize_t
+pstore_ftrace_combine_log(char **dest_log, size_t *dest_log_size,
+			  const char *src_log, size_t src_log_size)
+{
+	*dest_log_size = 0;
+	return 0;
+}
+#endif
+
+#ifdef CONFIG_PSTORE_PMSG
+extern void pstore_register_pmsg(void);
+extern void pstore_unregister_pmsg(void);
+#else
+static inline void pstore_register_pmsg(void) {}
+static inline void pstore_unregister_pmsg(void) {}
+#endif
+
+extern struct pstore_info *psinfo;
+
+extern void	pstore_set_kmsg_bytes(unsigned int bytes);
+extern void	pstore_get_records(int);
+extern void	pstore_get_backend_records(struct pstore_info *psi,
+					   struct dentry *root, int quiet);
+extern int	pstore_put_backend_records(struct pstore_info *psi);
+extern int	pstore_mkfile(struct dentry *root,
+			      struct pstore_record *record);
+extern void	pstore_record_init(struct pstore_record *record,
+				   struct pstore_info *psi);
+
+/* Called during pstore init/exit. */
+int __init	pstore_init_fs(void);
+void __exit	pstore_exit_fs(void);
+
+#endif