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, 39 insertions, 0 deletions

diff --git a/lib/zlib_inflate/infutil.h b/lib/zlib_inflate/infutil.h
new file mode 100644
index 000000000..784ab33b7
--- /dev/null
+++ b/lib/zlib_inflate/infutil.h
@@ -0,0 +1,39 @@
+/* infutil.h -- types and macros common to blocks and codes
+ * Copyright (C) 1995-1998 Mark Adler
+ * For conditions of distribution and use, see copyright notice in zlib.h 
+ */
+
+/* WARNING: this file should *not* be used by applications. It is
+   part of the implementation of the compression library and is
+   subject to change. Applications should only use zlib.h.
+ */
+
+#ifndef _INFUTIL_H
+#define _INFUTIL_H
+
+#include <linux/zlib.h>
+#ifdef CONFIG_ZLIB_DFLTCC
+#include "../zlib_dfltcc/dfltcc.h"
+#include <asm/page.h>
+#endif
+
+/* memory allocation for inflation */
+
+struct inflate_workspace {
+	struct inflate_state inflate_state;
+#ifdef CONFIG_ZLIB_DFLTCC
+	struct dfltcc_state dfltcc_state;
+	unsigned char working_window[(1 << MAX_WBITS) + PAGE_SIZE];
+#else
+	unsigned char working_window[(1 << MAX_WBITS)];
+#endif
+};
+
+#ifdef CONFIG_ZLIB_DFLTCC
+/* dfltcc_state must be doubleword aligned for DFLTCC call */
+static_assert(offsetof(struct inflate_workspace, dfltcc_state) % 8 == 0);
+#endif
+
+#define WS(strm) ((struct inflate_workspace *)(strm->workspace))
+
+#endif