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/objtool/sync-check.sh | 77 +++++++++++++++++++++++++++++++++++++++++++++ 1 file changed, 77 insertions(+) create mode 100755 tools/objtool/sync-check.sh (limited to 'tools/objtool/sync-check.sh') diff --git a/tools/objtool/sync-check.sh b/tools/objtool/sync-check.sh new file mode 100755 index 000000000..e38167ca5 --- /dev/null +++ b/tools/objtool/sync-check.sh @@ -0,0 +1,77 @@ +#!/bin/sh +# SPDX-License-Identifier: GPL-2.0 + +if [ -z "$SRCARCH" ]; then + echo 'sync-check.sh: error: missing $SRCARCH environment variable' >&2 + exit 1 +fi + +FILES="include/linux/objtool_types.h" + +if [ "$SRCARCH" = "x86" ]; then +FILES="$FILES +arch/x86/include/asm/nops.h +arch/x86/include/asm/inat_types.h +arch/x86/include/asm/orc_types.h +arch/x86/include/asm/emulate_prefix.h +arch/x86/lib/x86-opcode-map.txt +arch/x86/tools/gen-insn-attr-x86.awk +include/linux/interval_tree_generic.h +include/linux/livepatch_external.h +include/linux/static_call_types.h +" + +SYNC_CHECK_FILES=' +arch/x86/include/asm/inat.h +arch/x86/include/asm/insn.h +arch/x86/lib/inat.c +arch/x86/lib/insn.c +' +fi + +check_2 () { + file1=$1 + file2=$2 + + shift + shift + + cmd="diff $* $file1 $file2 > /dev/null" + + test -f $file2 && { + eval $cmd || { + echo "Warning: Kernel ABI header at '$file1' differs from latest version at '$file2'" >&2 + echo diff -u $file1 $file2 + } + } +} + +check () { + file=$1 + + shift + + check_2 tools/$file $file $* +} + +if [ ! -d ../../kernel ] || [ ! -d ../../tools ] || [ ! -d ../objtool ]; then + exit 0 +fi + +cd ../.. + +while read -r file_entry; do + if [ -z "$file_entry" ]; then + continue + fi + + check $file_entry +done <