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/perf/hv-common.c | 40 ++++++++++++++++++++++++++++++++++++++++ 1 file changed, 40 insertions(+) create mode 100644 arch/powerpc/perf/hv-common.c (limited to 'arch/powerpc/perf/hv-common.c') diff --git a/arch/powerpc/perf/hv-common.c b/arch/powerpc/perf/hv-common.c new file mode 100644 index 000000000..0370518ed --- /dev/null +++ b/arch/powerpc/perf/hv-common.c @@ -0,0 +1,40 @@ +// SPDX-License-Identifier: GPL-2.0 +#include +#include + +#include "hv-gpci.h" +#include "hv-common.h" + +unsigned long hv_perf_caps_get(struct hv_perf_caps *caps) +{ + unsigned long r; + struct p { + struct hv_get_perf_counter_info_params params; + struct hv_gpci_system_performance_capabilities caps; + } __packed __aligned(sizeof(uint64_t)); + + struct p arg = { + .params = { + .counter_request = cpu_to_be32( + HV_GPCI_system_performance_capabilities), + .starting_index = cpu_to_be32(-1), + .counter_info_version_in = 0, + } + }; + + r = plpar_hcall_norets(H_GET_PERF_COUNTER_INFO, + virt_to_phys(&arg), sizeof(arg)); + + if (r) + return r; + + pr_devel("capability_mask: 0x%x\n", arg.caps.capability_mask); + + caps->version = arg.params.counter_info_version_out; + caps->collect_privileged = !!arg.caps.perf_collect_privileged; + caps->ga = !!(arg.caps.capability_mask & HV_GPCI_CM_GA); + caps->expanded = !!(arg.caps.capability_mask & HV_GPCI_CM_EXPANDED); + caps->lab = !!(arg.caps.capability_mask & HV_GPCI_CM_LAB); + + return r; +} -- cgit v1.3.1