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/Documentation/doc-guide/checktransupdate.rst b/Documentation/doc-guide/checktransupdate.rst
new file mode 100644
index 000000000..7b25375cc
--- /dev/null
+++ b/Documentation/doc-guide/checktransupdate.rst
@@ -0,0 +1,54 @@
+.. SPDX-License-Identifier: GPL-2.0
+
+Checking for needed translation updates
+=======================================
+
+This script helps track the translation status of the documentation in
+different locales, i.e., whether the documentation is up-to-date with
+the English counterpart.
+
+How it works
+------------
+
+It uses ``git log`` command to track the latest English commit from the
+translation commit (order by author date) and the latest English commits
+from HEAD. If any differences occur, the file is considered as out-of-date,
+then commits that need to be updated will be collected and reported.
+
+Features implemented
+
+-  check all files in a certain locale
+-  check a single file or a set of files
+-  provide options to change output format
+-  track the translation status of files that have no translation
+
+Usage
+-----
+
+::
+
+   tools/docs/checktransupdate.py --help
+
+Please refer to the output of argument parser for usage details.
+
+Samples
+
+-  ``tools/docs/checktransupdate.py -l zh_CN``
+   This will print all the files that need to be updated in the zh_CN locale.
+-  ``tools/docs/checktransupdate.py Documentation/translations/zh_CN/dev-tools/testing-overview.rst``
+   This will only print the status of the specified file.
+
+Then the output is something like:
+
+::
+
+    Documentation/dev-tools/kfence.rst
+    No translation in the locale of zh_CN
+
+    Documentation/translations/zh_CN/dev-tools/testing-overview.rst
+    commit 42fb9cfd5b18 ("Documentation: dev-tools: Add link to RV docs")
+    1 commits needs resolving in total
+
+Features to be implemented
+
+- files can be a folder instead of only a file