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/arc/plat-sim/Makefile | 6 ++++++ arch/arc/plat-sim/platform.c | 32 ++++++++++++++++++++++++++++++++ 2 files changed, 38 insertions(+) create mode 100644 arch/arc/plat-sim/Makefile create mode 100644 arch/arc/plat-sim/platform.c (limited to 'arch/arc/plat-sim') diff --git a/arch/arc/plat-sim/Makefile b/arch/arc/plat-sim/Makefile new file mode 100644 index 000000000..ea9389bf8 --- /dev/null +++ b/arch/arc/plat-sim/Makefile @@ -0,0 +1,6 @@ +# SPDX-License-Identifier: GPL-2.0-only +# +# Copyright (C) 2011-2012 Synopsys, Inc. (www.synopsys.com) +# + +obj-y := platform.o diff --git a/arch/arc/plat-sim/platform.c b/arch/arc/plat-sim/platform.c new file mode 100644 index 000000000..2bde2a6e3 --- /dev/null +++ b/arch/arc/plat-sim/platform.c @@ -0,0 +1,32 @@ +// SPDX-License-Identifier: GPL-2.0-only +/* + * ARC simulation Platform support code + * + * Copyright (C) 2012 Synopsys, Inc. (www.synopsys.com) + */ + +#include +#include + +/*----------------------- Machine Descriptions ------------------------------ + * + * Machine description is simply a set of platform/board specific callbacks + * This is not directly related to DeviceTree based dynamic device creation, + * however as part of early device tree scan, we also select the right + * callback set, by matching the DT compatible name. + */ + +static const char *simulation_compat[] __initconst = { +#ifdef CONFIG_ISA_ARCOMPACT + "snps,nsim", + "snps,nsimosci", +#else + "snps,nsimosci_hs", + "snps,zebu_hs", +#endif + NULL, +}; + +MACHINE_START(SIMULATION, "simulation") + .dt_compat = simulation_compat, +MACHINE_END -- cgit v1.3.1