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, 27 insertions, 0 deletions

diff --git a/drivers/net/netdevsim/Makefile b/drivers/net/netdevsim/Makefile
new file mode 100644
index 000000000..87718204f
--- /dev/null
+++ b/drivers/net/netdevsim/Makefile
@@ -0,0 +1,27 @@
+# SPDX-License-Identifier: GPL-2.0
+
+obj-$(CONFIG_NETDEVSIM) += netdevsim.o
+
+netdevsim-objs := \
+	netdev.o dev.o ethtool.o fib.o bus.o health.o hwstats.o udp_tunnels.o tc.o
+
+ifeq ($(CONFIG_BPF_SYSCALL),y)
+netdevsim-objs += \
+	bpf.o
+endif
+
+ifneq ($(CONFIG_XFRM_OFFLOAD),)
+netdevsim-objs += ipsec.o
+endif
+
+ifneq ($(CONFIG_PSAMPLE),)
+netdevsim-objs += psample.o
+endif
+
+ifneq ($(CONFIG_INET_PSP),)
+netdevsim-objs += psp.o
+endif
+
+ifneq ($(CONFIG_MACSEC),)
+netdevsim-objs += macsec.o
+endif