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, 45 insertions, 0 deletions

diff --git a/fs/ufs/Kconfig b/fs/ufs/Kconfig
new file mode 100644
index 000000000..9301e7ecd
--- /dev/null
+++ b/fs/ufs/Kconfig
@@ -0,0 +1,45 @@
+# SPDX-License-Identifier: GPL-2.0-only
+config UFS_FS
+	tristate "UFS file system support (read only)"
+	depends on BLOCK
+	select BUFFER_HEAD
+	help
+	  BSD and derivate versions of Unix (such as SunOS, FreeBSD, NetBSD,
+	  OpenBSD and NeXTstep) use a file system called UFS. Some System V
+	  Unixes can create and mount hard disk partitions and diskettes using
+	  this file system as well. Saying Y here will allow you to read from
+	  these partitions; if you also want to write to them, say Y to the
+	  experimental "UFS file system write support", below. Please read the
+	  file <file:Documentation/admin-guide/ufs.rst> for more information.
+
+          The recently released UFS2 variant (used in FreeBSD 5.x) is
+          READ-ONLY supported.
+
+	  Note that this option is generally not needed for floppies, since a
+	  good portable way to transport files and directories between unixes
+	  (and even other operating systems) is given by the tar program ("man
+	  tar" or preferably "info tar").
+
+	  When accessing NeXTstep files, you may need to convert them from the
+	  NeXT character set to the Latin1 character set; use the program
+	  recode ("info recode") for this purpose.
+
+	  To compile the UFS file system support as a module, choose M here: the
+	  module will be called ufs.
+
+	  If you haven't heard about all of this before, it's safe to say N.
+
+config UFS_FS_WRITE
+	bool "UFS file system write support (DANGEROUS)"
+	depends on UFS_FS
+	help
+	  Say Y here if you want to try writing to UFS partitions. This is
+	  experimental, so you should back up your UFS partitions beforehand.
+
+config UFS_DEBUG
+	bool "UFS debugging"
+	depends on UFS_FS
+	help
+	  If you are experiencing any problems with the UFS filesystem, say
+	  Y here.  This will result in _many_ additional debugging messages to be
+	  written to the system log.