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, 103 insertions, 0 deletions

diff --git a/Documentation/devicetree/bindings/Makefile b/Documentation/devicetree/bindings/Makefile
new file mode 100644
index 000000000..6b4b4f51c
--- /dev/null
+++ b/Documentation/devicetree/bindings/Makefile
@@ -0,0 +1,103 @@
+# SPDX-License-Identifier: GPL-2.0
+DT_DOC_CHECKER ?= dt-doc-validate
+DT_EXTRACT_EX ?= dt-extract-example
+DT_MK_SCHEMA ?= dt-mk-schema
+
+DT_SCHEMA_LINT = $(shell which yamllint || \
+  echo "warning: python package 'yamllint' not installed, skipping" >&2)
+
+DT_SCHEMA_MIN_VERSION = 2024.4
+
+PHONY += check_dtschema_version
+check_dtschema_version:
+	@which $(DT_DOC_CHECKER) >/dev/null || \
+		{ echo "Error: '$(DT_DOC_CHECKER)' not found!" >&2; \
+		  echo "Ensure dtschema python package is installed and in your PATH." >&2; \
+		  echo "Current PATH is:" >&2; \
+		  echo "$$PATH" >&2; false; }
+	@{ echo $(DT_SCHEMA_MIN_VERSION); \
+	$(DT_DOC_CHECKER) --version 2>/dev/null || echo 0; } | sort -Vc >/dev/null || \
+	{ echo "ERROR: dtschema minimum version is v$(DT_SCHEMA_MIN_VERSION)" >&2; false; }
+
+quiet_cmd_extract_ex = DTEX    $@
+      cmd_extract_ex = $(DT_EXTRACT_EX) $< > $@
+
+$(obj)/%.example.dts: $(src)/%.yaml check_dtschema_version FORCE
+	$(call if_changed,extract_ex)
+
+find_all_cmd = find $(src) \( -name '*.yaml' ! \
+		-name 'processed-schema*' \)
+
+find_cmd = $(find_all_cmd) | \
+		sed 's|^$(srctree)/||' | \
+		grep -F -e "$(subst :," -e ",$(DT_SCHEMA_FILES))" | \
+		sed 's|^|$(srctree)/|'
+CHK_DT_EXAMPLES := $(patsubst $(srctree)/%.yaml,%.example.dtb, \
+			      $(shell $(find_cmd) | xargs grep -l '^examples:'))
+
+quiet_cmd_yamllint = LINT    $(src)
+      cmd_yamllint = ($(find_cmd) | \
+                     xargs -n200 -P$$(nproc) \
+		     $(DT_SCHEMA_LINT) -f parsable -c $(src)/.yamllint >&2) \
+		     && touch $@ || true
+
+quiet_cmd_chk_bindings = CHKDT   $(src)
+      cmd_chk_bindings = ($(find_cmd) | \
+			  xargs -n200 -P$$(nproc) $(DT_DOC_CHECKER) -u $(src)) \
+			  && touch $@ || true
+
+DT_CHK_STYLE = $(srctree)/scripts/dtc/dt-check-style
+
+# Feed the file list to the checker via @argfile in a single Python
+# process so the ruamel.yaml import is paid once. scripts/jobserver-exec
+# claims slots from the GNU make jobserver and exposes the count via
+# $PARALLELISM, which dt-check-style picks up to size its worker pool.
+quiet_cmd_chk_style = STYLE   $(src)
+      cmd_chk_style = f=$$(mktemp) && $(find_cmd) > $$f && \
+		      $(PYTHON3) $(srctree)/scripts/jobserver-exec \
+		      $(PYTHON3) $(DT_CHK_STYLE) @$$f \
+		      && touch $@ || true; rm -f $$f
+
+quiet_cmd_mk_schema = SCHEMA  $@
+      cmd_mk_schema = f=$$(mktemp) ; \
+                      $(find_all_cmd) > $$f ; \
+                      $(DT_MK_SCHEMA) -j $(DT_MK_SCHEMA_FLAGS) @$$f > $@ ; \
+		      rm -f $$f
+
+DT_DOCS = $(patsubst $(srctree)/%,%,$(shell $(find_all_cmd)))
+
+override DTC_FLAGS := \
+	-Wno-avoid_unnecessary_addr_size \
+	-Wno-unique_unit_address \
+	-Wunique_unit_address_if_enabled
+
+$(obj)/processed-schema.json: $(DT_DOCS) check_dtschema_version FORCE
+	$(call if_changed,mk_schema)
+
+targets += .dt-binding.checked .yamllint.checked .dt-style.checked
+$(obj)/.yamllint.checked: $(DT_DOCS) $(src)/.yamllint FORCE
+	$(if $(DT_SCHEMA_LINT),$(call if_changed,yamllint),)
+
+$(obj)/.dt-binding.checked: $(DT_DOCS) FORCE
+	$(call if_changed,chk_bindings)
+
+$(obj)/.dt-style.checked: $(DT_DOCS) FORCE
+	$(call if_changed,chk_style)
+
+always-y += processed-schema.json
+targets += $(patsubst $(obj)/%,%, $(CHK_DT_EXAMPLES))
+targets += $(patsubst $(obj)/%.dtb,%.dts, $(CHK_DT_EXAMPLES))
+
+# Hack: avoid 'Argument list too long' error for 'make clean'. Remove most of
+# build artifacts here before they are processed by scripts/Makefile.clean
+clean-files = $(shell find $(obj) \( -name '*.example.dts' -o \
+			-name '*.example.dtb' \) -delete 2>/dev/null)
+
+dt_compatible_check: $(obj)/processed-schema.json
+	$(Q)$(srctree)/scripts/dtc/dt-extract-compatibles $(srctree) | xargs dt-check-compatible -v -s $<
+
+PHONY += dt_binding_check_one
+dt_binding_check_one: $(obj)/.dt-binding.checked $(obj)/.yamllint.checked $(obj)/.dt-style.checked
+
+PHONY += dt_binding_check
+dt_binding_check: dt_binding_check_one $(CHK_DT_EXAMPLES)