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/dma/amd/Kconfig b/drivers/dma/amd/Kconfig
new file mode 100644
index 000000000..00d874872
--- /dev/null
+++ b/drivers/dma/amd/Kconfig
@@ -0,0 +1,42 @@
+# SPDX-License-Identifier: GPL-2.0-only
+#
+
+config AMD_AE4DMA
+	tristate  "AMD AE4DMA Engine"
+	depends on (X86_64 || COMPILE_TEST) && PCI
+	depends on AMD_PTDMA
+	select DMA_ENGINE
+	select DMA_VIRTUAL_CHANNELS
+	help
+	  Enable support for the AMD AE4DMA controller. This controller
+	  provides DMA capabilities to perform high bandwidth memory to
+	  memory and IO copy operations. It performs DMA transfer through
+	  queue-based descriptor management. This DMA controller is intended
+	  to be used with AMD Non-Transparent Bridge devices and not for
+	  general purpose peripheral DMA.
+
+config AMD_PTDMA
+	tristate  "AMD PassThru DMA Engine"
+	depends on X86_64 && PCI
+	select DMA_ENGINE
+	select DMA_VIRTUAL_CHANNELS
+	help
+	  Enable support for the AMD PTDMA controller. This controller
+	  provides DMA capabilities to perform high bandwidth memory to
+	  memory and IO copy operations. It performs DMA transfer through
+	  queue-based descriptor management. This DMA controller is intended
+	  to be used with AMD Non-Transparent Bridge devices and not for
+	  general purpose peripheral DMA.
+
+config AMD_QDMA
+	tristate "AMD Queue-based DMA"
+	depends on HAS_IOMEM
+	select DMA_ENGINE
+	select DMA_VIRTUAL_CHANNELS
+	select REGMAP_MMIO
+	help
+	  Enable support for the AMD Queue-based DMA subsystem. The primary
+	  mechanism to transfer data using the QDMA is for the QDMA engine to
+	  operate on instructions (descriptors) provided by the host operating
+	  system. Using the descriptors, the QDMA can move data in either the
+	  Host to Card (H2C) direction or the Card to Host (C2H) direction.