From 6668ed271eaefaa63e686bdfbedaeb7b8e492722 Mon Sep 17 00:00:00 2001 From: Kumar Kartikeya Dwivedi Date: Fri, 4 Sep 2026 10:43:19 +0200 Subject: selftests/bpf: Reject graph kptr use after RCU unlock 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 Link: https://lore.kernel.org/r/20260904084325.52250-7-memxor@gmail.com Signed-off-by: Alexei Starovoitov --- tools/virtio/ringtest/Makefile | 31 +++++++++++++++++++++++++++++++ 1 file changed, 31 insertions(+) create mode 100644 tools/virtio/ringtest/Makefile (limited to 'tools/virtio/ringtest/Makefile') diff --git a/tools/virtio/ringtest/Makefile b/tools/virtio/ringtest/Makefile new file mode 100644 index 000000000..85c98c281 --- /dev/null +++ b/tools/virtio/ringtest/Makefile @@ -0,0 +1,31 @@ +# SPDX-License-Identifier: GPL-2.0 +all: + +all: ring virtio_ring_0_9 virtio_ring_poll virtio_ring_inorder ptr_ring noring + +CFLAGS += -Wall +CFLAGS += -pthread -O2 -ggdb -flto -fwhole-program +LDFLAGS += -pthread -O2 -ggdb -flto -fwhole-program + +main.o: main.c main.h +ring.o: ring.c main.h +ptr_ring.o: ptr_ring.c main.h ../../../include/linux/ptr_ring.h +virtio_ring_0_9.o: virtio_ring_0_9.c main.h +virtio_ring_poll.o: virtio_ring_poll.c virtio_ring_0_9.c main.h +virtio_ring_inorder.o: virtio_ring_inorder.c virtio_ring_0_9.c main.h +ring: ring.o main.o +virtio_ring_0_9: virtio_ring_0_9.o main.o +virtio_ring_poll: virtio_ring_poll.o main.o +virtio_ring_inorder: virtio_ring_inorder.o main.o +ptr_ring: ptr_ring.o main.o +noring: noring.o main.o +clean: + -rm main.o + -rm ring.o ring + -rm virtio_ring_0_9.o virtio_ring_0_9 + -rm virtio_ring_poll.o virtio_ring_poll + -rm virtio_ring_inorder.o virtio_ring_inorder + -rm ptr_ring.o ptr_ring + -rm noring.o noring + +.PHONY: all clean -- cgit v1.3.1