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, 41 insertions, 0 deletions

diff --git a/fs/smb/server/unicode.h b/fs/smb/server/unicode.h
new file mode 100644
index 000000000..28c7c736f
--- /dev/null
+++ b/fs/smb/server/unicode.h
@@ -0,0 +1,41 @@
+/* SPDX-License-Identifier: GPL-2.0-or-later */
+/*
+ * Some of the source code in this file came from fs/cifs/cifs_unicode.c
+ * cifs_unicode:  Unicode kernel case support
+ *
+ * Function:
+ *     Convert a unicode character to upper or lower case using
+ *     compressed tables.
+ *
+ *   Copyright (c) International Business Machines  Corp., 2000,2009
+ *
+ *
+ * Notes:
+ *     These APIs are based on the C library functions.  The semantics
+ *     should match the C functions but with expanded size operands.
+ *
+ *     The upper/lower functions are based on a table created by mkupr.
+ *     This is a compressed table of upper and lower case conversion.
+ *
+ */
+#ifndef _SMB_UNICODE_H
+#define _SMB_UNICODE_H
+
+#include <asm/byteorder.h>
+#include <linux/types.h>
+#include <linux/nls.h>
+#include <linux/unicode.h>
+#include "../../nls/nls_ucs2_utils.h"
+
+#ifdef __KERNEL__
+int smb_strtoUTF16(__le16 *to, const char *from, int len,
+		   const struct nls_table *codepage);
+char *smb_strndup_from_utf16(const char *src, const int maxlen,
+			     const bool is_unicode,
+			     const struct nls_table *codepage);
+int smbConvertToUTF16(__le16 *target, const char *source, int srclen,
+		      const struct nls_table *cp, int mapchars);
+char *ksmbd_extract_sharename(struct unicode_map *um, const char *treename);
+#endif
+
+#endif /* _SMB_UNICODE_H */