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/vdso/elf.S | 65 ++++++++++++++++++++++++++++++++++++++++++++++++++++ 1 file changed, 65 insertions(+) create mode 100644 arch/mips/vdso/elf.S (limited to 'arch/mips/vdso/elf.S') diff --git a/arch/mips/vdso/elf.S b/arch/mips/vdso/elf.S new file mode 100644 index 000000000..821fcffe7 --- /dev/null +++ b/arch/mips/vdso/elf.S @@ -0,0 +1,65 @@ +/* SPDX-License-Identifier: GPL-2.0-or-later */ +/* + * Copyright (C) 2015 Imagination Technologies + * Author: Alex Smith + */ + +#include + +#include + +#include +#include +#include + +ELFNOTE_START(Linux, 0, "a") + .long LINUX_VERSION_CODE +ELFNOTE_END + +BUILD_SALT + +/* + * The .MIPS.abiflags section must be defined with the FP ABI flags set + * to 'any' to be able to link with both old and new libraries. + * Newer toolchains are capable of automatically generating this, but we want + * to work with older toolchains as well. Therefore, we define the contents of + * this section here (under different names), and then genvdso will patch + * it to have the correct name and type. + * + * We base the .MIPS.abiflags section on preprocessor definitions rather than + * CONFIG_* because we need to match the particular ABI we are building the + * VDSO for. + * + * See https://dmz-portal.mips.com/wiki/MIPS_O32_ABI_-_FR0_and_FR1_Interlinking + * for the .MIPS.abiflags section description. + */ + + .section .mips_abiflags, "a" + .align 3 +__mips_abiflags: + .hword 0 /* version */ + .byte __mips /* isa_level */ + + /* isa_rev */ + .byte MIPS_ISA_REV + + /* gpr_size */ +#ifdef __mips64 + .byte 2 /* AFL_REG_64 */ +#else + .byte 1 /* AFL_REG_32 */ +#endif + + /* cpr1_size */ +#if (MIPS_ISA_REV >= 6) || defined(__mips64) + .byte 2 /* AFL_REG_64 */ +#else + .byte 1 /* AFL_REG_32 */ +#endif + + .byte 0 /* cpr2_size (AFL_REG_NONE) */ + .byte 0 /* fp_abi (Val_GNU_MIPS_ABI_FP_ANY) */ + .word 0 /* isa_ext */ + .word 0 /* ases */ + .word 0 /* flags1 */ + .word 0 /* flags2 */ -- cgit v1.3.1