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/arm/mach-versatile/v2m.c | 40 ++++++++++++++++++++++++++++++++++++++++ 1 file changed, 40 insertions(+) create mode 100644 arch/arm/mach-versatile/v2m.c (limited to 'arch/arm/mach-versatile/v2m.c') diff --git a/arch/arm/mach-versatile/v2m.c b/arch/arm/mach-versatile/v2m.c new file mode 100644 index 000000000..79afdf2a9 --- /dev/null +++ b/arch/arm/mach-versatile/v2m.c @@ -0,0 +1,40 @@ +// SPDX-License-Identifier: GPL-2.0 +#include +#include +#include + +#include "vexpress.h" + +#define SYS_FLAGSSET 0x030 +#define SYS_FLAGSCLR 0x034 + +void vexpress_flags_set(u32 data) +{ + static void __iomem *base; + + if (!base) { + struct device_node *node = of_find_compatible_node(NULL, NULL, + "arm,vexpress-sysreg"); + + base = of_iomap(node, 0); + } + + if (WARN_ON(!base)) + return; + + writel(~0, base + SYS_FLAGSCLR); + writel(data, base + SYS_FLAGSSET); +} + +static const char * const v2m_dt_match[] __initconst = { + "arm,vexpress", + NULL, +}; + +DT_MACHINE_START(VEXPRESS_DT, "ARM-Versatile Express") + .dt_compat = v2m_dt_match, + .l2c_aux_val = 0x00400000, + .l2c_aux_mask = 0xfe0fffff, + .smp = smp_ops(vexpress_smp_dt_ops), + .smp_init = smp_init_ops(vexpress_smp_init_ops), +MACHINE_END -- cgit v1.3.1