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, 14 insertions, 0 deletions

diff --git a/drivers/usb/usbip/Makefile b/drivers/usb/usbip/Makefile
new file mode 100644
index 000000000..f4c8f3840
--- /dev/null
+++ b/drivers/usb/usbip/Makefile
@@ -0,0 +1,14 @@
+# SPDX-License-Identifier: GPL-2.0
+ccflags-$(CONFIG_USBIP_DEBUG) := -DDEBUG
+
+obj-$(CONFIG_USBIP_CORE) += usbip-core.o
+usbip-core-y := usbip_common.o usbip_event.o
+
+obj-$(CONFIG_USBIP_VHCI_HCD) += vhci-hcd.o
+vhci-hcd-y := vhci_sysfs.o vhci_tx.o vhci_rx.o vhci_hcd.o
+
+obj-$(CONFIG_USBIP_HOST) += usbip-host.o
+usbip-host-y := stub_dev.o stub_main.o stub_rx.o stub_tx.o
+
+obj-$(CONFIG_USBIP_VUDC) += usbip-vudc.o
+usbip-vudc-y := vudc_dev.o vudc_sysfs.o vudc_tx.o vudc_rx.o vudc_transfer.o vudc_main.o