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 --- scripts/dummy-tools/ld | 30 ++++++++++++++++++++++++++++++ 1 file changed, 30 insertions(+) create mode 100755 scripts/dummy-tools/ld (limited to 'scripts/dummy-tools/ld') diff --git a/scripts/dummy-tools/ld b/scripts/dummy-tools/ld new file mode 100755 index 000000000..f68233050 --- /dev/null +++ b/scripts/dummy-tools/ld @@ -0,0 +1,30 @@ +#!/bin/sh +# SPDX-License-Identifier: GPL-2.0-only + +# Dummy script that always succeeds. + +# Check if the first parameter appears in the rest. Succeeds if found. +# This helper is useful if a particular option was passed to this script. +# Typically used like this: +# arg_contain "$@" +arg_contain () +{ + search="$1" + shift + + while [ $# -gt 0 ] + do + if [ "$search" = "$1" ]; then + return 0 + fi + shift + done + + return 1 +} + +if arg_contain --version "$@" || arg_contain -v "$@"; then + progname=$(basename $0) + echo "GNU $progname (scripts/dummy-tools/$progname) 2.50" + exit 0 +fi -- cgit v1.3.1