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 --- drivers/acpi/acpi_ffh.c | 53 +++++++++++++++++++++++++++++++++++++++++++++++++ 1 file changed, 53 insertions(+) create mode 100644 drivers/acpi/acpi_ffh.c (limited to 'drivers/acpi/acpi_ffh.c') diff --git a/drivers/acpi/acpi_ffh.c b/drivers/acpi/acpi_ffh.c new file mode 100644 index 000000000..8d5126963 --- /dev/null +++ b/drivers/acpi/acpi_ffh.c @@ -0,0 +1,53 @@ +// SPDX-License-Identifier: GPL-2.0-only +/* + * Author: Sudeep Holla + * Copyright 2022 Arm Limited + */ +#include +#include +#include +#include +#include + +static struct acpi_ffh_info ffh_ctx; + +int __weak acpi_ffh_address_space_arch_setup(void *handler_ctxt, + void **region_ctxt) +{ + return -EOPNOTSUPP; +} + +int __weak acpi_ffh_address_space_arch_handler(acpi_integer *value, + void *region_context) +{ + return -EOPNOTSUPP; +} + +static acpi_status +acpi_ffh_address_space_setup(acpi_handle region_handle, u32 function, + void *handler_context, void **region_context) +{ + return acpi_ffh_address_space_arch_setup(handler_context, + region_context); +} + +static acpi_status +acpi_ffh_address_space_handler(u32 function, acpi_physical_address addr, + u32 bits, acpi_integer *value, + void *handler_context, void *region_context) +{ + return acpi_ffh_address_space_arch_handler(value, region_context); +} + +void __init acpi_init_ffh(void) +{ + acpi_status status; + + status = acpi_install_address_space_handler(ACPI_ROOT_OBJECT, + ACPI_ADR_SPACE_FIXED_HARDWARE, + &acpi_ffh_address_space_handler, + &acpi_ffh_address_space_setup, + &ffh_ctx); + if (ACPI_FAILURE(status)) + pr_alert("OperationRegion handler could not be installed\n"); +} -- cgit v1.3.1