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, 30 insertions, 0 deletions

diff --git a/fs/hfs/Kconfig b/fs/hfs/Kconfig
new file mode 100644
index 000000000..7f3cbe43b
--- /dev/null
+++ b/fs/hfs/Kconfig
@@ -0,0 +1,30 @@
+# SPDX-License-Identifier: GPL-2.0-only
+config HFS_FS
+	tristate "Apple Macintosh file system support"
+	depends on BLOCK
+	select BUFFER_HEAD
+	select NLS
+	select LEGACY_DIRECT_IO
+	help
+	  If you say Y here, you will be able to mount Macintosh-formatted
+	  floppy disks and hard drive partitions with full read-write access.
+	  Please read <file:Documentation/filesystems/hfs.rst> to learn about
+	  the available mount options.
+
+	  To compile this file system support as a module, choose M here: the
+	  module will be called hfs.
+
+config HFS_KUNIT_TEST
+	tristate "KUnit tests for HFS filesystem" if !KUNIT_ALL_TESTS
+	depends on HFS_FS && KUNIT
+	default KUNIT_ALL_TESTS
+	help
+	  This builds KUnit tests for the HFS filesystem.
+
+	  KUnit tests run during boot and output the results to the debug
+	  log in TAP format (https://testanything.org/). Only useful for
+	  kernel devs running KUnit test harness and are not for inclusion
+	  into a production build.
+
+	  For more information on KUnit and unit tests in general please
+	  refer to the KUnit documentation in Documentation/dev-tools/kunit/.