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 --- arch/powerpc/tools/gcc-check-mprofile-kernel.sh | 26 +++++++++++++++++++++++++ 1 file changed, 26 insertions(+) create mode 100755 arch/powerpc/tools/gcc-check-mprofile-kernel.sh (limited to 'arch/powerpc/tools/gcc-check-mprofile-kernel.sh') diff --git a/arch/powerpc/tools/gcc-check-mprofile-kernel.sh b/arch/powerpc/tools/gcc-check-mprofile-kernel.sh new file mode 100755 index 000000000..6193b0ed0 --- /dev/null +++ b/arch/powerpc/tools/gcc-check-mprofile-kernel.sh @@ -0,0 +1,26 @@ +#!/bin/bash +# SPDX-License-Identifier: GPL-2.0 + +set -e + +# To debug, uncomment the following line +# set -x + +# -mprofile-kernel is only supported on 64-bit with ELFv2, so this should not +# be invoked for other targets. Therefore we can pass in -m64 and -mabi +# explicitly, to take care of toolchains defaulting to other targets. + +# Test whether the compile option -mprofile-kernel exists and generates +# profiling code (ie. a call to _mcount()). +echo "int func() { return 0; }" | \ + $* -m64 -mabi=elfv2 -S -x c -O2 -p -mprofile-kernel - -o - \ + 2> /dev/null | grep -q "_mcount" + +# Test whether the notrace attribute correctly suppresses calls to _mcount(). + +echo -e "#include \nnotrace int func() { return 0; }" | \ + $* -m64 -mabi=elfv2 -S -x c -O2 -p -mprofile-kernel - -o - \ + 2> /dev/null | grep -q "_mcount" && \ + exit 1 + +exit 0 -- cgit v1.3.1