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, 65 insertions, 0 deletions

diff --git a/arch/arm64/configs/virt.config b/arch/arm64/configs/virt.config
new file mode 100644
index 000000000..2d1d2ce7a
--- /dev/null
+++ b/arch/arm64/configs/virt.config
@@ -0,0 +1,65 @@
+# Help: Virtualization guest
+#
+# Base options for platforms
+#
+
+# CONFIG_ARCH_ACTIONS is not set
+# CONFIG_ARCH_SUNXI is not set
+# CONFIG_ARCH_ALPINE is not set
+# CONFIG_ARCH_APPLE is not set
+# CONFIG_ARCH_BCM is not set
+# CONFIG_ARCH_BCM2835 is not set
+# CONFIG_ARCH_BCMBCA is not set
+# CONFIG_ARCH_BCM_IPROC is not set
+# CONFIG_ARCH_BERLIN is not set
+# CONFIG_ARCH_BRCMSTB is not set
+# CONFIG_ARCH_EXYNOS is not set
+# CONFIG_ARCH_SPARX5 is not set
+# CONFIG_ARCH_K3 is not set
+# CONFIG_ARCH_LAYERSCAPE is not set
+# CONFIG_ARCH_LG1K is not set
+# CONFIG_ARCH_HISI is not set
+# CONFIG_ARCH_KEEMBAY is not set
+# CONFIG_ARCH_MEDIATEK is not set
+# CONFIG_ARCH_MESON is not set
+# CONFIG_ARCH_MVEBU is not set
+# CONFIG_ARCH_NXP is not set
+# CONFIG_ARCH_MA35 is not set
+# CONFIG_ARCH_MXC is not set
+# CONFIG_ARCH_NPCM is not set
+# CONFIG_ARCH_QCOM is not set
+# CONFIG_ARCH_REALTEK is not set
+# CONFIG_ARCH_RENESAS is not set
+# CONFIG_ARCH_ROCKCHIP is not set
+# CONFIG_ARCH_S32 is not set
+# CONFIG_ARCH_SEATTLE is not set
+# CONFIG_ARCH_INTEL_SOCFPGA is not set
+# CONFIG_ARCH_STM32 is not set
+# CONFIG_ARCH_SYNQUACER is not set
+# CONFIG_ARCH_TEGRA is not set
+# CONFIG_ARCH_TESLA_FSD is not set
+# CONFIG_ARCH_SPRD is not set
+# CONFIG_ARCH_THUNDER is not set
+# CONFIG_ARCH_THUNDER2 is not set
+# CONFIG_ARCH_UNIPHIER is not set
+# CONFIG_ARCH_VEXPRESS is not set
+# CONFIG_ARCH_VISCONTI is not set
+# CONFIG_ARCH_XGENE is not set
+# CONFIG_ARCH_ZYNQMP is not set
+
+#
+# Subsystems which can't be used in mach-virt
+#
+# CONFIG_CHROME_PLATFORMS is not set
+# CONFIG_EXTCON is not set
+# CONFIG_IIO is not set
+# CONFIG_MTD is not set
+# CONFIG_NEW_LEDS is not set
+# CONFIG_PWM is not set
+# CONFIG_REGULATOR is not set
+# CONFIG_SLIMBUS is not set
+# CONFIG_SND_SOC is not set
+# CONFIG_SOUNDWIRE is not set
+# CONFIG_SPI is not set
+# CONFIG_SURFACE_PLATFORMS is not set
+# CONFIG_THERMAL is not set