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, 18 insertions, 0 deletions

diff --git a/drivers/char/agp/Makefile b/drivers/char/agp/Makefile
new file mode 100644
index 000000000..43b09cf19
--- /dev/null
+++ b/drivers/char/agp/Makefile
@@ -0,0 +1,18 @@
+# SPDX-License-Identifier: GPL-2.0
+agpgart-y := backend.o generic.o isoch.o
+
+obj-$(CONFIG_AGP)		+= agpgart.o
+obj-$(CONFIG_AGP_ALI)		+= ali-agp.o
+obj-$(CONFIG_AGP_ATI)		+= ati-agp.o
+obj-$(CONFIG_AGP_AMD)		+= amd-k7-agp.o
+obj-$(CONFIG_AGP_AMD64)		+= amd64-agp.o
+obj-$(CONFIG_AGP_ALPHA_CORE)	+= alpha-agp.o
+obj-$(CONFIG_AGP_EFFICEON)	+= efficeon-agp.o
+obj-$(CONFIG_AGP_PARISC)	+= parisc-agp.o
+obj-$(CONFIG_AGP_INTEL)		+= intel-agp.o
+obj-$(CONFIG_INTEL_GTT)		+= intel-gtt.o
+obj-$(CONFIG_AGP_NVIDIA)	+= nvidia-agp.o
+obj-$(CONFIG_AGP_SIS)		+= sis-agp.o
+obj-$(CONFIG_AGP_SWORKS)	+= sworks-agp.o
+obj-$(CONFIG_AGP_UNINORTH)	+= uninorth-agp.o
+obj-$(CONFIG_AGP_VIA)		+= via-agp.o