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/reset.c | 52 ++++++++++++++++++++++++++++++++++++++++++++++++ 1 file changed, 52 insertions(+) create mode 100644 arch/mips/cobalt/reset.c (limited to 'arch/mips/cobalt/reset.c') diff --git a/arch/mips/cobalt/reset.c b/arch/mips/cobalt/reset.c new file mode 100644 index 000000000..4eedd481d --- /dev/null +++ b/arch/mips/cobalt/reset.c @@ -0,0 +1,52 @@ +/* + * Cobalt Reset operations + * + * This file is subject to the terms and conditions of the GNU General Public + * License. See the file "COPYING" in the main directory of this archive + * for more details. + * + * Copyright (C) 1995, 1996, 1997 by Ralf Baechle + * Copyright (C) 2001 by Liam Davies (ldavies@agile.tv) + */ +#include +#include +#include + +#include +#include + +#include + +#define RESET_PORT ((void __iomem *)CKSEG1ADDR(0x1c000000)) +#define RESET 0x0f + +DEFINE_LED_TRIGGER(power_off_led_trigger); + +static int __init ledtrig_power_off_init(void) +{ + led_trigger_register_simple("power-off", &power_off_led_trigger); + return 0; +} +device_initcall(ledtrig_power_off_init); + +void cobalt_machine_halt(void) +{ + /* + * turn on power off LED on RaQ + */ + led_trigger_event(power_off_led_trigger, LED_FULL); + + local_irq_disable(); + while (1) { + if (cpu_wait) + cpu_wait(); + } +} + +void cobalt_machine_restart(char *command) +{ + writeb(RESET, RESET_PORT); + + /* we should never get here */ + cobalt_machine_halt(); +} -- cgit v1.3.1