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/treeboot-bamboo.c | 40 +++++++++++++++++++++++++++++++++++++ 1 file changed, 40 insertions(+) create mode 100644 arch/powerpc/boot/treeboot-bamboo.c (limited to 'arch/powerpc/boot/treeboot-bamboo.c') diff --git a/arch/powerpc/boot/treeboot-bamboo.c b/arch/powerpc/boot/treeboot-bamboo.c new file mode 100644 index 000000000..97b5b161d --- /dev/null +++ b/arch/powerpc/boot/treeboot-bamboo.c @@ -0,0 +1,40 @@ +// SPDX-License-Identifier: GPL-2.0-only +/* + * Copyright IBM Corporation, 2007 + * Josh Boyer + * + * Based on ebony wrapper: + * Copyright 2007 David Gibson, IBM Corporation. + */ +#include "ops.h" +#include "stdio.h" +#include "44x.h" +#include "stdlib.h" + +BSS_STACK(4096); + +#define PIBS_MAC0 0xfffc0400 +#define PIBS_MAC1 0xfffc0500 +char pibs_mac0[6]; +char pibs_mac1[6]; + +static void read_pibs_mac(void) +{ + unsigned long long mac64; + + mac64 = strtoull((char *)PIBS_MAC0, 0, 16); + memcpy(&pibs_mac0, (char *)&mac64+2, 6); + + mac64 = strtoull((char *)PIBS_MAC1, 0, 16); + memcpy(&pibs_mac1, (char *)&mac64+2, 6); +} + +void platform_init(void) +{ + unsigned long end_of_ram = 0x8000000; + unsigned long avail_ram = end_of_ram - (unsigned long)_end; + + simple_alloc_init(_end, avail_ram, 32, 64); + read_pibs_mac(); + bamboo_init((u8 *)&pibs_mac0, (u8 *)&pibs_mac1); +} -- cgit v1.3.1