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/cobalt/time.c | 41 +++++++++++++++++++++++++++++++++++++++++ 1 file changed, 41 insertions(+) create mode 100644 arch/mips/cobalt/time.c (limited to 'arch/mips/cobalt/time.c') diff --git a/arch/mips/cobalt/time.c b/arch/mips/cobalt/time.c new file mode 100644 index 000000000..1b6fa6649 --- /dev/null +++ b/arch/mips/cobalt/time.c @@ -0,0 +1,41 @@ +// SPDX-License-Identifier: GPL-2.0-or-later +/* + * Cobalt time initialization. + * + * Copyright (C) 2007 Yoichi Yuasa + */ +#include +#include + +#include +#include + +#define GT641XX_BASE_CLOCK 50000000 /* 50MHz */ + +void __init plat_time_init(void) +{ + u32 start, end; + int i = HZ / 10; + + setup_pit_timer(); + + gt641xx_set_base_clock(GT641XX_BASE_CLOCK); + + /* + * MIPS counter frequency is measured during a 100msec interval + * using GT64111 timer0. + */ + while (!gt641xx_timer0_state()) + ; + + start = read_c0_count(); + + while (i--) + while (!gt641xx_timer0_state()) + ; + + end = read_c0_count(); + + mips_hpt_frequency = (end - start) * 10; + printk(KERN_INFO "MIPS counter frequency %dHz\n", mips_hpt_frequency); +} -- cgit v1.3.1