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-shmobile/timer.c | 41 +++++++++++++++++++++++++++++++++++++++++ 1 file changed, 41 insertions(+) create mode 100644 arch/arm/mach-shmobile/timer.c (limited to 'arch/arm/mach-shmobile/timer.c') diff --git a/arch/arm/mach-shmobile/timer.c b/arch/arm/mach-shmobile/timer.c new file mode 100644 index 000000000..2335311b5 --- /dev/null +++ b/arch/arm/mach-shmobile/timer.c @@ -0,0 +1,41 @@ +// SPDX-License-Identifier: GPL-2.0 +/* + * SH-Mobile Timer + * + * Copyright (C) 2010 Magnus Damm + * Copyright (C) 2002 - 2009 Paul Mundt + */ +#include +#include +#include +#include + +#include "common.h" + +void __init shmobile_init_delay(void) +{ + struct device_node *np; + u32 max_freq = 0; + + for_each_of_cpu_node(np) { + u32 freq; + + if (!of_property_read_u32(np, "clock-frequency", &freq)) + max_freq = max(max_freq, freq); + } + + if (!max_freq) + return; + + /* + * Calculate a worst-case loops-per-jiffy value + * based on maximum cpu core hz setting and the + * __delay() implementation in arch/arm/lib/delay.S. + * + * This will result in a longer delay than expected + * when the cpu core runs on lower frequencies. + */ + + if (!preset_lpj) + preset_lpj = max_freq / HZ; +} -- cgit v1.3.1