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, 51 insertions, 0 deletions

diff --git a/fs/jfs/Kconfig b/fs/jfs/Kconfig
new file mode 100644
index 000000000..3728cf4d9
--- /dev/null
+++ b/fs/jfs/Kconfig
@@ -0,0 +1,51 @@
+# SPDX-License-Identifier: GPL-2.0-only
+config JFS_FS
+	tristate "JFS filesystem support"
+	select BUFFER_HEAD
+	select NLS
+	select NLS_UCS2_UTILS
+	select CRC32
+	select LEGACY_DIRECT_IO
+	help
+	  This is a port of IBM's Journaled Filesystem .  More information is
+	  available in the file <file:Documentation/admin-guide/jfs.rst>.
+
+	  If you do not intend to use the JFS filesystem, say N.
+
+config JFS_POSIX_ACL
+	bool "JFS POSIX Access Control Lists"
+	depends on JFS_FS
+	select FS_POSIX_ACL
+	help
+	  Posix Access Control Lists (ACLs) support permissions for users and
+	  groups beyond the owner/group/world scheme.
+
+	  If you don't know what Access Control Lists are, say N
+
+config JFS_SECURITY
+	bool "JFS Security Labels"
+	depends on JFS_FS
+	help
+	  Security labels support alternative access control models
+	  implemented by security modules like SELinux.  This option
+	  enables an extended attribute handler for file security
+	  labels in the jfs filesystem.
+
+	  If you are not using a security module that requires using
+	  extended attributes for file security labels, say N.
+
+config JFS_DEBUG
+	bool "JFS debugging"
+	depends on JFS_FS
+	help
+	  If you are experiencing any problems with the JFS filesystem, say
+	  Y here.  This will result in additional debugging messages to be
+	  written to the system log.  Under normal circumstances, this
+	  results in very little overhead.
+
+config JFS_STATISTICS
+	bool "JFS statistics"
+	depends on JFS_FS
+	help
+	  Enabling this option will cause statistics from the JFS file system
+	  to be made available to the user in the /proc/fs/jfs/ directory.