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/page.h | 30 ++++++++++++++++++++++++++++++ 1 file changed, 30 insertions(+) create mode 100644 arch/powerpc/boot/page.h (limited to 'arch/powerpc/boot/page.h') diff --git a/arch/powerpc/boot/page.h b/arch/powerpc/boot/page.h new file mode 100644 index 000000000..e44a31197 --- /dev/null +++ b/arch/powerpc/boot/page.h @@ -0,0 +1,30 @@ +/* SPDX-License-Identifier: GPL-2.0-or-later */ +#ifndef _PPC_BOOT_PAGE_H +#define _PPC_BOOT_PAGE_H +/* + * Copyright (C) 2001 PPC64 Team, IBM Corp + */ + +#ifdef __ASSEMBLER__ +#define ASM_CONST(x) x +#else +#define __ASM_CONST(x) x##UL +#define ASM_CONST(x) __ASM_CONST(x) +#endif + +/* PAGE_SHIFT determines the page size */ +#define PAGE_SHIFT 12 +#define PAGE_SIZE (ASM_CONST(1) << PAGE_SHIFT) +#define PAGE_MASK (~(PAGE_SIZE-1)) + +/* align addr on a size boundary - adjust address up/down if needed */ +#define _ALIGN_UP(addr, size) (((addr)+((size)-1))&(~((typeof(addr))(size)-1))) +#define _ALIGN_DOWN(addr, size) ((addr)&(~((typeof(addr))(size)-1))) + +/* align addr on a size boundary - adjust address up if needed */ +#define _ALIGN(addr,size) _ALIGN_UP(addr,size) + +/* to align the pointer to the (next) page boundary */ +#define PAGE_ALIGN(addr) _ALIGN(addr, PAGE_SIZE) + +#endif /* _PPC_BOOT_PAGE_H */ -- cgit v1.3.1