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/boot/cuboot.c | 29 +++++++++++++++++++++++++++++ 1 file changed, 29 insertions(+) create mode 100644 arch/powerpc/boot/cuboot.c (limited to 'arch/powerpc/boot/cuboot.c') diff --git a/arch/powerpc/boot/cuboot.c b/arch/powerpc/boot/cuboot.c new file mode 100644 index 000000000..7f186658f --- /dev/null +++ b/arch/powerpc/boot/cuboot.c @@ -0,0 +1,29 @@ +// SPDX-License-Identifier: GPL-2.0-only +/* + * Compatibility for old (not device tree aware) U-Boot versions + * + * Author: Scott Wood + * Consolidated using macros by David Gibson + * + * Copyright 2007 David Gibson, IBM Corporation. + * Copyright (c) 2007 Freescale Semiconductor, Inc. + */ + +#include "ops.h" +#include "stdio.h" + +#include "ppcboot.h" + +void cuboot_init(unsigned long r4, unsigned long r5, + unsigned long r6, unsigned long r7, + unsigned long end_of_ram) +{ + unsigned long avail_ram = end_of_ram - (unsigned long)_end; + + loader_info.initrd_addr = r4; + loader_info.initrd_size = r4 ? r5 - r4 : 0; + loader_info.cmdline = (char *)r6; + loader_info.cmdline_len = r7 - r6; + + simple_alloc_init(_end, avail_ram - 1024*1024, 32, 64); +} -- cgit v1.3.1