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, 71 insertions, 0 deletions

diff --git a/lib/crc/Makefile b/lib/crc/Makefile
new file mode 100644
index 000000000..386e9c175
--- /dev/null
+++ b/lib/crc/Makefile
@@ -0,0 +1,71 @@
+# SPDX-License-Identifier: GPL-2.0-only
+
+# Makefile for the kernel's cyclic redundancy check (CRC) library code
+
+obj-$(CONFIG_CRC4) += crc4.o
+obj-$(CONFIG_CRC7) += crc7.o
+obj-$(CONFIG_CRC8) += crc8.o
+obj-$(CONFIG_CRC16) += crc16.o
+obj-$(CONFIG_CRC_CCITT) += crc-ccitt.o
+obj-$(CONFIG_CRC_ITU_T) += crc-itu-t.o
+
+obj-$(CONFIG_CRC_T10DIF) += crc-t10dif.o
+crc-t10dif-y := crc-t10dif-main.o
+ifeq ($(CONFIG_CRC_T10DIF_ARCH),y)
+CFLAGS_crc-t10dif-main.o += -I$(src)/$(SRCARCH)
+crc-t10dif-$(CONFIG_ARM) += arm/crc-t10dif-core.o
+crc-t10dif-$(CONFIG_ARM64) += arm64/crc-t10dif-core.o
+crc-t10dif-$(CONFIG_PPC) += powerpc/crct10dif-vpmsum_asm.o
+crc-t10dif-$(CONFIG_RISCV) += riscv/crc16_msb.o
+crc-t10dif-$(CONFIG_X86) += x86/crc16-msb-pclmul.o
+endif
+
+obj-$(CONFIG_CRC32) += crc32.o
+crc32-y := crc32-main.o
+ifeq ($(CONFIG_CRC32_ARCH),y)
+CFLAGS_crc32-main.o += -I$(src)/$(SRCARCH)
+crc32-$(CONFIG_ARM) += arm/crc32-core.o
+crc32-$(CONFIG_ARM64) += arm64/crc32-core.o
+crc32-$(CONFIG_PPC) += powerpc/crc32c-vpmsum_asm.o
+crc32-$(CONFIG_RISCV) += riscv/crc32_lsb.o riscv/crc32_msb.o
+crc32-$(CONFIG_S390) += s390/crc32le-vx.o s390/crc32be-vx.o
+crc32-$(CONFIG_SPARC) += sparc/crc32c_asm.o
+crc32-$(CONFIG_X86) += x86/crc32-pclmul.o
+crc32-$(CONFIG_X86_64) += x86/crc32c-3way.o
+endif
+
+obj-$(CONFIG_CRC64) += crc64.o
+crc64-y := crc64-main.o
+ifeq ($(CONFIG_CRC64_ARCH),y)
+CFLAGS_crc64-main.o += -I$(src)/$(SRCARCH)
+
+crc64-cflags-$(CONFIG_ARM) += -march=armv8-a -mfpu=crypto-neon-fp-armv8
+crc64-cflags-$(CONFIG_ARM64) += -march=armv8-a+crypto
+CFLAGS_REMOVE_crc64-neon.o += $(CC_FLAGS_NO_FPU)
+CFLAGS_crc64-neon.o += $(CC_FLAGS_FPU) -I$(src)/$(SRCARCH) $(crc64-cflags-y)
+crc64-$(CONFIG_ARM) += crc64-neon.o
+crc64-$(CONFIG_ARM64) += crc64-neon.o
+
+crc64-$(CONFIG_RISCV) += riscv/crc64_lsb.o riscv/crc64_msb.o
+crc64-$(CONFIG_X86) += x86/crc64-pclmul.o
+endif # CONFIG_CRC64_ARCH
+
+obj-y += tests/
+
+hostprogs := gen_crc32table gen_crc64table
+clean-files := crc32table.h crc64table.h
+
+$(obj)/crc32-main.o: $(obj)/crc32table.h
+$(obj)/crc64-main.o: $(obj)/crc64table.h
+
+quiet_cmd_crc32 = GEN     $@
+      cmd_crc32 = $< > $@
+
+quiet_cmd_crc64 = GEN     $@
+      cmd_crc64 = $< > $@
+
+$(obj)/crc32table.h: $(obj)/gen_crc32table
+	$(call cmd,crc32)
+
+$(obj)/crc64table.h: $(obj)/gen_crc64table
+	$(call cmd,crc64)