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, 75 insertions, 0 deletions

diff --git a/lib/raid/Kconfig b/lib/raid/Kconfig
new file mode 100644
index 000000000..01f007b25
--- /dev/null
+++ b/lib/raid/Kconfig
@@ -0,0 +1,75 @@
+# SPDX-License-Identifier: GPL-2.0
+
+config XOR_BLOCKS
+	tristate
+
+# selected by architectures that provide an optimized XOR implementation
+config XOR_BLOCKS_ARCH
+	depends on XOR_BLOCKS
+	default y if ALPHA
+	default y if ARM
+	default y if ARM64
+	default y if CPU_HAS_LSX		# loongarch
+	default y if ALTIVEC			# powerpc
+	default y if RISCV_ISA_V
+	default y if SPARC
+	default y if S390
+	default y if X86_32
+	default y if X86_64
+	bool
+
+config XOR_KUNIT_TEST
+	tristate "KUnit tests for xor_gen" if !KUNIT_ALL_TESTS
+	depends on KUNIT
+	depends on XOR_BLOCKS
+	default KUNIT_ALL_TESTS
+	help
+	  Unit tests for the XOR library functions.
+
+	  This is intended to help people writing architecture-specific
+	  optimized versions.  If unsure, say N.
+
+config XOR_BENCHMARK
+	bool "Benchmark for xor_gen"
+	depends on XOR_KUNIT_TEST
+	help
+	  Include benchmarks in the KUnit test suite for xor_gen.
+
+config RAID6_PQ
+	tristate
+
+# selected by architectures that provide an optimized PQ implementation
+config RAID6_PQ_ARCH
+	depends on RAID6_PQ
+	default y if KERNEL_MODE_NEON		# arm32/arm64
+	default y if LOONGARCH
+	default y if ALTIVEC			# powerpc
+	default y if RISCV_ISA_V
+	default y if S390
+	default y if X86
+	bool
+
+config RAID6_PQ_KUNIT_TEST
+	tristate "KUnit tests for RAID6 PQ functions" if !KUNIT_ALL_TESTS
+	depends on KUNIT
+	depends on RAID6_PQ
+	default KUNIT_ALL_TESTS
+	help
+	  Unit tests for the RAID6 PQ library functions.
+
+	  This is intended to help people writing architecture-specific
+	  optimized versions.  If unsure, say N.
+
+config RAID6_PQ_KUNIT_BENCHMARK
+	bool "Benchmark for RAID6 PQ"
+	depends on RAID6_PQ_KUNIT_TEST
+	help
+	  Include benchmarks in the KUnit test suite for raid P/Q generation.
+
+config RAID6_PQ_BENCHMARK
+	bool "Automatically choose fastest RAID6 PQ functions"
+	depends on RAID6_PQ
+	default y
+	help
+	  Benchmark all available RAID6 PQ functions on init and choose the
+	  fastest one.