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/makelst | 32 ++++++++++++++++++++++++++++++++ 1 file changed, 32 insertions(+) create mode 100755 scripts/makelst (limited to 'scripts/makelst') diff --git a/scripts/makelst b/scripts/makelst new file mode 100755 index 000000000..e432af073 --- /dev/null +++ b/scripts/makelst @@ -0,0 +1,32 @@ +#!/bin/sh +# SPDX-License-Identifier: GPL-2.0 +# A script to dump mixed source code & assembly +# with correct relocations from System.map +# Requires the following lines in makefile: +#%.lst: %.c +# $(CC) $(c_flags) -g -c -o $*.o $< && +# $(srctree)/scripts/makelst $*.o System.map $(OBJDUMP) > $@ +# +# Copyright (C) 2000 IBM Corporation +# Author(s): DJ Barrow (djbarrow@de.ibm.com,barrow_dj@yahoo.com) +# William Stearns +# + +# awk style field access +field() { + shift $1 ; echo $1 +} + +t1=`$3 --syms $1 | grep .text | grep -m1 " F "` +if [ -n "$t1" ]; then + t2=`field 6 $t1` + if [ ! -r $2 ]; then + echo "No System.map" >&2 + else + t3=`grep $t2 $2` + t4=`field 1 $t3` + t5=`field 1 $t1` + t6=`printf "%lu" $((0x$t4 - 0x$t5))` + fi +fi +$3 -r --source --adjust-vma=${t6:-0} $1 -- cgit v1.3.1