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/mips/power/cpu.c | 43 +++++++++++++++++++++++++++++++++++++++++++ 1 file changed, 43 insertions(+) create mode 100644 arch/mips/power/cpu.c (limited to 'arch/mips/power/cpu.c') diff --git a/arch/mips/power/cpu.c b/arch/mips/power/cpu.c new file mode 100644 index 000000000..d8ef7778e --- /dev/null +++ b/arch/mips/power/cpu.c @@ -0,0 +1,43 @@ +// SPDX-License-Identifier: GPL-2.0-only +/* + * Suspend support specific for mips. + * + * Copyright (C) 2009 Lemote Inc. + * Author: Hu Hongbing + * Wu Zhangjin + */ +#include +#include +#include +#include + +static u32 saved_status; +struct pt_regs saved_regs; + +void save_processor_state(void) +{ + saved_status = read_c0_status(); + + if (is_fpu_owner()) + save_fp(current); + + save_dsp(current); +} + +void restore_processor_state(void) +{ + write_c0_status(saved_status); + + if (is_fpu_owner()) + restore_fp(current); + + restore_dsp(current); +} + +int pfn_is_nosave(unsigned long pfn) +{ + unsigned long nosave_begin_pfn = PFN_DOWN(__pa(&__nosave_begin)); + unsigned long nosave_end_pfn = PFN_UP(__pa(&__nosave_end)); + + return (pfn >= nosave_begin_pfn) && (pfn < nosave_end_pfn); +} -- cgit v1.3.1