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, 128 insertions, 0 deletions

diff --git a/Documentation/filesystems/befs.rst b/Documentation/filesystems/befs.rst
new file mode 100644
index 000000000..a22f603b2
--- /dev/null
+++ b/Documentation/filesystems/befs.rst
@@ -0,0 +1,128 @@
+.. SPDX-License-Identifier: GPL-2.0
+
+=========================
+BeOS filesystem for Linux
+=========================
+
+Document last updated: Dec 6, 2001
+
+Warning
+=======
+Make sure you understand that this is alpha software.  This means that the
+implementation is neither complete nor well-tested.
+
+I DISCLAIM ALL RESPONSIBILITY FOR ANY POSSIBLE BAD EFFECTS OF THIS CODE!
+
+License
+=======
+This software is covered by the GNU General Public License.
+See the file COPYING for the complete text of the license.
+Or the GNU website: <http://www.gnu.org/licenses/licenses.html>
+
+Author
+======
+The largest part of the code written by Will Dyson <will_dyson@pobox.com>
+He has been working on the code since Aug 13, 2001. See the changelog for
+details.
+
+Original Author: Makoto Kato <m_kato@ga2.so-net.ne.jp>
+
+His original code can still be found at:
+<http://hp.vector.co.jp/authors/VA008030/bfs/>
+
+Does anyone know of a more current email address for Makoto? He doesn't
+respond to the address given above...
+
+This filesystem doesn't have a maintainer.
+
+What is this Driver?
+====================
+This module implements the native filesystem of BeOS http://www.beincorporated.com/
+for the linux 2.4.1 and later kernels. Currently it is a read-only
+implementation.
+
+Which is it, BFS or BEFS?
+=========================
+Be, Inc said, "BeOS Filesystem is officially called BFS, not BeFS".
+But Unixware Boot Filesystem is called bfs, too. And they are already in
+the kernel. Because of this naming conflict, on Linux the BeOS
+filesystem is called befs.
+
+How to Install
+==============
+step 1.  Install the BeFS  patch into the source code tree of linux.
+
+Apply the patchfile to your kernel source tree.
+Assuming that your kernel source is in /foo/bar/linux and the patchfile
+is called patch-befs-xxx, you would do the following:
+
+	cd /foo/bar/linux
+	patch -p1 < /path/to/patch-befs-xxx
+
+if the patching step fails (i.e. there are rejected hunks), you can try to
+figure it out yourself (it shouldn't be hard), or mail the maintainer
+(Will Dyson <will_dyson@pobox.com>) for help.
+
+step 2.  Configuration & make kernel
+
+The linux kernel has many compile-time options. Most of them are beyond the
+scope of this document. I suggest the Kernel-HOWTO document as a good general
+reference on this topic. http://www.linuxdocs.org/HOWTOs/Kernel-HOWTO-4.html
+
+However, to use the BeFS module, you must enable it at configure time::
+
+	cd /foo/bar/linux
+	make menuconfig (or xconfig)
+
+The BeFS module is not a standard part of the linux kernel, so you must first
+enable support for experimental code under the "Code maturity level" menu.
+
+Then, under the "Filesystems" menu will be an option called "BeFS
+filesystem (experimental)", or something like that. Enable that option
+(it is fine to make it a module).
+
+Save your kernel configuration and then build your kernel.
+
+step 3.  Install
+
+See the kernel howto <http://www.linux.com/howto/Kernel-HOWTO.html> for
+instructions on this critical step.
+
+Using BFS
+=========
+To use the BeOS filesystem, use filesystem type 'befs'.
+
+ex::
+
+    mount -t befs /dev/fd0 /beos
+
+Mount Options
+=============
+
+=============  ===========================================================
+uid=nnn        All files in the partition will be owned by user id nnn.
+gid=nnn	       All files in the partition will be in group nnn.
+iocharset=xxx  Use xxx as the name of the NLS translation table.
+debug          The driver will output debugging information to the syslog.
+=============  ===========================================================
+
+How to Get Latest Version
+=========================
+
+The latest version is currently available at:
+<http://befs-driver.sourceforge.net/>
+
+Any Known Bugs?
+===============
+As of Jan 20, 2002:
+
+	None
+
+Special Thanks
+==============
+Dominic Giampalo ... Writing "Practical file system design with Be filesystem"
+
+Hiroyuki Yamada  ... Testing LinuxPPC.
+
+
+