selftests/bpf: Reject graph kptr use after RCU unlockgrafted

Add a sleepable verifier test that loads a graph-node local kptr in an
explicit RCU read-side critical section, then passes its node to
bpf_rbtree_remove() after the section ends.

Before the verifier fix, the stale NON_OWN_REF flag makes the node look like
a live borrowed reference and the program is accepted. After the fix, the
pointer is demoted without NON_OWN_REF and the graph kfunc argument is
rejected.

Also exercise a graph kptr loaded while a spin lock provides implicit RCU
protection. The pointer must be invalidated when the lock is released, which
guards the required ordering between non-owning-reference invalidation and
RCU demotion.

Update the existing fault-protected load test state description. The
post-unlock pointer no longer carries NON_OWN_REF, but remains readable
because the load is rewritten to use BPF_PROBE_MEM.

Signed-off-by: Kumar Kartikeya Dwivedi <memxor@gmail.com>
Link: https://lore.kernel.org/r/20260904084325.52250-7-memxor@gmail.com
Signed-off-by: Alexei Starovoitov <ast@kernel.org>

1 files changed, 159 insertions, 0 deletions

diff --git a/tools/lib/thermal/Makefile b/tools/lib/thermal/Makefile
new file mode 100644
index 000000000..41aa7a324
--- /dev/null
+++ b/tools/lib/thermal/Makefile
@@ -0,0 +1,159 @@
+# SPDX-License-Identifier: (LGPL-2.1 OR BSD-2-Clause)
+# Most of this file is copied from tools/lib/perf/Makefile
+
+LIBTHERMAL_VERSION = 0
+LIBTHERMAL_PATCHLEVEL = 0
+LIBTHERMAL_EXTRAVERSION = 1
+
+MAKEFLAGS += --no-print-directory
+
+ifeq ($(srctree),)
+srctree := $(patsubst %/,%,$(dir $(CURDIR)))
+srctree := $(patsubst %/,%,$(dir $(srctree)))
+srctree := $(patsubst %/,%,$(dir $(srctree)))
+# $(info Determined 'srctree' to be $(srctree))
+endif
+
+INSTALL = install
+
+# Use DESTDIR for installing into a different root directory.
+# This is useful for building a package. The program will be
+# installed in this directory as if it was the root directory.
+# Then the build tool can move it later.
+DESTDIR ?=
+DESTDIR_SQ = '$(subst ','\'',$(DESTDIR))'
+
+include $(srctree)/tools/scripts/Makefile.include
+include $(srctree)/tools/scripts/Makefile.arch
+
+ifeq ($(LP64), 1)
+  libdir_relative = lib64
+else
+  libdir_relative = lib
+endif
+
+prefix ?=
+libdir = $(prefix)/$(libdir_relative)
+
+# Shell quotes
+libdir_SQ = $(subst ','\'',$(libdir))
+libdir_relative_SQ = $(subst ','\'',$(libdir_relative))
+
+# Set compile option CFLAGS
+ifdef EXTRA_CFLAGS
+  CFLAGS := $(EXTRA_CFLAGS)
+else
+  CFLAGS := -g -Wall
+endif
+
+NL3_CFLAGS = $(shell pkg-config --cflags libnl-3.0 2>/dev/null)
+ifeq ($(NL3_CFLAGS),)
+NL3_CFLAGS = -I/usr/include/libnl3
+endif
+
+INCLUDES = \
+-I$(srctree)/tools/lib/thermal/include \
+-I$(srctree)/tools/lib/ \
+-I$(srctree)/tools/include \
+-I$(srctree)/tools/arch/$(SRCARCH)/include/ \
+-I$(srctree)/tools/arch/$(SRCARCH)/include/uapi \
+-I$(srctree)/tools/include/uapi
+
+# Append required CFLAGS
+override CFLAGS += $(EXTRA_WARNINGS)
+override CFLAGS += -Werror -Wall
+override CFLAGS += -fPIC
+override CFLAGS += $(NL3_CFLAGS)
+override CFLAGS += $(INCLUDES)
+override CFLAGS += -fvisibility=hidden
+override CFGLAS += -Wl,-L.
+override CFGLAS += -Wl,-lthermal
+
+all:
+
+export srctree OUTPUT CC LD CFLAGS V
+export DESTDIR DESTDIR_SQ
+
+include $(srctree)/tools/build/Makefile.include
+
+VERSION_SCRIPT := libthermal.map
+
+PATCHLEVEL    = $(LIBTHERMAL_PATCHLEVEL)
+EXTRAVERSION  = $(LIBTHERMAL_EXTRAVERSION)
+VERSION       = $(LIBTHERMAL_VERSION).$(LIBTHERMAL_PATCHLEVEL).$(LIBTHERMAL_EXTRAVERSION)
+
+LIBTHERMAL_SO := $(OUTPUT)libthermal.so.$(VERSION)
+LIBTHERMAL_A  := $(OUTPUT)libthermal.a
+LIBTHERMAL_IN := $(OUTPUT)libthermal-in.o
+LIBTHERMAL_PC := $(OUTPUT)libthermal.pc
+LIBTHERMAL_ALL := $(LIBTHERMAL_A) $(OUTPUT)libthermal.so*
+
+THERMAL_UAPI := include/uapi/linux/thermal.h
+
+$(THERMAL_UAPI): FORCE
+	ln -sf $(srctree)/$@ $(srctree)/tools/$@
+
+$(LIBTHERMAL_IN): FORCE
+	$(Q)$(MAKE) $(build)=libthermal
+
+$(LIBTHERMAL_A): $(LIBTHERMAL_IN)
+	$(QUIET_AR)$(RM) $@ && $(AR) rcs $@ $(LIBTHERMAL_IN)
+
+$(LIBTHERMAL_SO): $(LIBTHERMAL_IN)
+	$(QUIET_LINK)$(CC) --shared -Wl,-soname,libthermal.so \
+                                    -Wl,--version-script=$(VERSION_SCRIPT) $^ -o $@
+	@ln -sf $(@F) $(OUTPUT)libthermal.so
+	@ln -sf $(@F) $(OUTPUT)libthermal.so.$(LIBTHERMAL_VERSION)
+
+
+libs: $(THERMAL_UAPI) $(LIBTHERMAL_A) $(LIBTHERMAL_SO) $(LIBTHERMAL_PC)
+
+all: fixdep
+	$(Q)$(MAKE) libs
+
+clean:
+	$(call QUIET_CLEAN, libthermal) $(RM) $(LIBTHERMAL_A) \
+                *.o *~ *.a *.so *.so.$(VERSION) *.so.$(LIBTHERMAL_VERSION) \
+                .*.d .*.cmd LIBTHERMAL-CFLAGS $(LIBTHERMAL_PC) \
+                $(srctree)/tools/$(THERMAL_UAPI)
+
+$(LIBTHERMAL_PC):
+	$(QUIET_GEN)sed -e "s|@PREFIX@|$(prefix)|" \
+		-e "s|@LIBDIR@|$(libdir_SQ)|" \
+		-e "s|@VERSION@|$(VERSION)|" \
+		< libthermal.pc.template > $@
+
+define do_install_mkdir
+	if [ ! -d '$(DESTDIR_SQ)$1' ]; then             \
+		$(INSTALL) -d -m 755 '$(DESTDIR_SQ)$1'; \
+	fi
+endef
+
+define do_install
+	if [ ! -d '$(DESTDIR_SQ)$2' ]; then             \
+		$(INSTALL) -d -m 755 '$(DESTDIR_SQ)$2'; \
+	fi;                                             \
+	$(INSTALL) $1 $(if $3,-m $3,) '$(DESTDIR_SQ)$2'
+endef
+
+install_lib: libs
+	$(call QUIET_INSTALL, $(LIBTHERMAL_ALL)) \
+		$(call do_install_mkdir,$(libdir_SQ)); \
+		cp -fR --preserve=mode,timestamp $(LIBTHERMAL_ALL) $(DESTDIR)$(libdir_SQ)
+
+install_headers:
+	$(call QUIET_INSTALL, headers) \
+		$(call do_install,include/thermal.h,$(prefix)/include/thermal,644); \
+
+install_pkgconfig: $(LIBTHERMAL_PC)
+	$(call QUIET_INSTALL, $(LIBTHERMAL_PC)) \
+		$(call do_install,$(LIBTHERMAL_PC),$(libdir_SQ)/pkgconfig,644)
+
+install_doc:
+	$(Q)$(MAKE) -C Documentation install-man install-html install-examples
+
+install: install_lib install_headers install_pkgconfig
+
+FORCE:
+
+.PHONY: all install clean FORCE