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/ntfs/ntfs_codec.h b/fs/ntfs/ntfs_codec.h
new file mode 100644
index 000000000..6030055fb
--- /dev/null
+++ b/fs/ntfs/ntfs_codec.h
@@ -0,0 +1,54 @@
+/* SPDX-License-Identifier: GPL-2.0-or-later */
+/*
+ * Transparent compression codec interface.
+ *
+ * Copyright (c) 2026 LG Electronics Co., Ltd.
+ */
+
+#ifndef _NTFS_CODEC_H
+#define _NTFS_CODEC_H
+
+#include <linux/types.h>
+#include <linux/fs.h>
+#include <linux/mm.h>
+
+struct compress_context;
+
+enum ntfs_codec_id {
+	NTFS_CODEC_LZNT1,
+#ifdef CONFIG_NTFS_FS_WOF_COMPRESSION
+	NTFS_CODEC_XPRESS4K,
+	NTFS_CODEC_XPRESS8K,
+	NTFS_CODEC_XPRESS16K,
+	NTFS_CODEC_LZX32K,
+#endif
+};
+
+struct ntfs_codec_ops {
+	enum ntfs_codec_id id;
+	const char *name;
+	size_t (*scratch_size)(u32 chunk_size);
+	int (*decompress_chunk)(void *scratch,
+				const void *src, size_t src_len,
+				void *dst, size_t dst_len,
+				u32 chunk_size);
+	int (*decompress_pages)(struct page *dest_pages[],
+				int completed_pages[],
+				int *dest_index, int *dest_ofs,
+				int dest_max_index, int dest_max_ofs,
+				int xpage, char *xpage_done,
+				u8 *cb_start, u32 cb_size,
+				loff_t i_size, s64 initialized_size);
+	int (*compress_subblock)(struct compress_context *pctx,
+				 const char *inbuf, int bufsize, char *outbuf);
+};
+
+extern const struct ntfs_codec_ops ntfs_lznt1_codec_ops;
+#ifdef CONFIG_NTFS_FS_WOF_COMPRESSION
+extern const struct ntfs_codec_ops ntfs_xpress4k_codec_ops;
+extern const struct ntfs_codec_ops ntfs_xpress8k_codec_ops;
+extern const struct ntfs_codec_ops ntfs_xpress16k_codec_ops;
+extern const struct ntfs_codec_ops ntfs_lzx32k_codec_ops;
+#endif
+
+#endif /* _NTFS_CODEC_H */