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, 42 insertions, 0 deletions

diff --git a/drivers/nvmem/layouts/Kconfig b/drivers/nvmem/layouts/Kconfig
new file mode 100644
index 000000000..5e586dfeb
--- /dev/null
+++ b/drivers/nvmem/layouts/Kconfig
@@ -0,0 +1,42 @@
+# SPDX-License-Identifier: GPL-2.0
+
+config NVMEM_LAYOUTS
+	bool
+	depends on OF
+
+if NVMEM_LAYOUTS
+
+menu "Layout Types"
+
+config NVMEM_LAYOUT_SL28_VPD
+	tristate "Kontron sl28 VPD layout support"
+	select CRC8
+	help
+	  Say Y here if you want to support the VPD layout of the Kontron
+	  SMARC-sAL28 boards.
+
+	  If unsure, say N.
+
+config NVMEM_LAYOUT_ONIE_TLV
+	tristate "ONIE tlv support"
+	select CRC32
+	help
+	  Say Y here if you want to support the Open Compute Project ONIE
+	  Type-Length-Value standard table.
+
+	  If unsure, say N.
+
+config NVMEM_LAYOUT_U_BOOT_ENV
+	tristate "U-Boot environment variables layout"
+	select CRC32
+	select GENERIC_NET_UTILS
+	help
+	  U-Boot stores its setup as environment variables. This driver adds
+	  support for verifying & exporting such data. It also exposes variables
+	  as NVMEM cells so they can be referenced by other drivers.
+
+	  If unsure, say N.
+
+endmenu
+
+endif