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, 36 insertions, 0 deletions

diff --git a/fs/gfs2/Kconfig b/fs/gfs2/Kconfig
new file mode 100644
index 000000000..8beee571b
--- /dev/null
+++ b/fs/gfs2/Kconfig
@@ -0,0 +1,36 @@
+# SPDX-License-Identifier: GPL-2.0-only
+config GFS2_FS
+	tristate "GFS2 file system support"
+	select BUFFER_HEAD
+	select FS_POSIX_ACL
+	select CRC32
+	select QUOTACTL
+	select FS_IOMAP
+	help
+	  A cluster filesystem.
+
+	  Allows a cluster of computers to simultaneously use a block device
+	  that is shared between them (with FC, iSCSI, NBD, etc...).  GFS reads
+	  and writes to the block device like a local filesystem, but also uses
+	  a lock module to allow the computers coordinate their I/O so
+	  filesystem consistency is maintained.  One of the nifty features of
+	  GFS is perfect consistency -- changes made to the filesystem on one
+	  machine show up immediately on all other machines in the cluster.
+
+	  To use the GFS2 filesystem in a cluster, you will need to enable
+	  the locking module below. Documentation and utilities for GFS2 can
+	  be found here: http://sources.redhat.com/cluster
+
+	  The "nolock" lock module is now built in to GFS2 by default. If
+	  you want to use the DLM, be sure to enable IPv4/6 networking.
+
+config GFS2_FS_LOCKING_DLM
+	bool "GFS2 DLM locking"
+	depends on (GFS2_FS!=n) && NET && INET && \
+		CONFIGFS_FS && SYSFS && (DLM=y || DLM=GFS2_FS)
+	help
+	  Multiple node locking module for GFS2
+
+	  Most users of GFS2 will require this. It provides the locking
+	  interface between GFS2 and the DLM, which is required to use GFS2
+	  in a cluster environment.