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, 63 insertions, 0 deletions

diff --git a/net/9p/Kconfig b/net/9p/Kconfig
new file mode 100644
index 000000000..22f8c1678
--- /dev/null
+++ b/net/9p/Kconfig
@@ -0,0 +1,63 @@
+# SPDX-License-Identifier: GPL-2.0-only
+#
+# 9P protocol configuration
+#
+
+menuconfig NET_9P
+	tristate "Plan 9 Resource Sharing Support (9P2000)"
+	select NETFS_SUPPORT
+	help
+	  If you say Y here, you will get experimental support for
+	  Plan 9 resource sharing via the 9P2000 protocol.
+
+	  See <http://v9fs.sf.net> for more information.
+
+	  If unsure, say N.
+
+if NET_9P
+
+config NET_9P_FD
+	default NET_9P
+	imply INET
+	imply UNIX
+	tristate "9P FD Transport"
+	help
+	  This builds support for transports over TCP, Unix sockets and
+	  filedescriptors.
+
+config NET_9P_VIRTIO
+	depends on VIRTIO
+	tristate "9P Virtio Transport"
+	help
+	  This builds support for a transports between
+	  guest partitions and a host partition.
+
+config NET_9P_XEN
+	depends on XEN
+	select XEN_XENBUS_FRONTEND
+	tristate "9P Xen Transport"
+	help
+	  This builds support for a transport for 9pfs between
+	  two Xen domains.
+
+config NET_9P_USBG
+	tristate "9P USB Gadget Transport"
+	depends on USB_GADGET
+	select CONFIGFS_FS
+	select USB_LIBCOMPOSITE
+	help
+	  This builds support for a transport for 9pfs over
+	  usb gadget.
+
+config NET_9P_RDMA
+	depends on INET && INFINIBAND && INFINIBAND_ADDR_TRANS
+	tristate "9P RDMA Transport (Experimental)"
+	help
+	  This builds support for an RDMA transport.
+
+config NET_9P_DEBUG
+	bool "Debug information"
+	help
+	  Say Y if you want the 9P subsystem to log debug information.
+
+endif