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, 28 insertions, 0 deletions

diff --git a/fs/befs/Kconfig b/fs/befs/Kconfig
new file mode 100644
index 000000000..5fcfc4024
--- /dev/null
+++ b/fs/befs/Kconfig
@@ -0,0 +1,28 @@
+# SPDX-License-Identifier: GPL-2.0-only
+config BEFS_FS
+	tristate "BeOS file system (BeFS) support (read only)"
+	depends on BLOCK
+	select BUFFER_HEAD
+	select NLS
+	help
+	  The BeOS File System (BeFS) is the native file system of Be, Inc's
+	  BeOS. Notable features include support for arbitrary attributes
+	  on files and directories, and database-like indices on selected
+	  attributes. (Also note that this driver doesn't make those features
+	  available at this time). It is a 64 bit filesystem, so it supports
+	  extremely large volumes and files.
+
+	  If you use this filesystem, you should also say Y to at least one
+	  of the NLS (native language support) options below.
+
+	  If you don't know what this is about, say N.
+
+	  To compile this as a module, choose M here: the module will be
+	  called befs.
+
+config BEFS_DEBUG
+	bool "Debug BeFS"
+	depends on BEFS_FS
+	help
+	  If you say Y here, you can use the 'debug' mount option to enable
+	  debugging output from the driver.