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/powerpc/boot/ofconsole.c | 43 +++++++++++++++++++++++++++++++++++++++++++ 1 file changed, 43 insertions(+) create mode 100644 arch/powerpc/boot/ofconsole.c (limited to 'arch/powerpc/boot/ofconsole.c') diff --git a/arch/powerpc/boot/ofconsole.c b/arch/powerpc/boot/ofconsole.c new file mode 100644 index 000000000..8eb0f1c45 --- /dev/null +++ b/arch/powerpc/boot/ofconsole.c @@ -0,0 +1,43 @@ +// SPDX-License-Identifier: GPL-2.0-or-later +/* + * OF console routines + * + * Copyright (C) Paul Mackerras 1997. + */ +#include +#include "types.h" +#include "elf.h" +#include "string.h" +#include "stdio.h" +#include "page.h" +#include "ops.h" + +#include "of.h" + +static unsigned int of_stdout_handle; + +static int of_console_open(void) +{ + void *devp; + + if (((devp = of_finddevice("/chosen")) != NULL) + && (of_getprop(devp, "stdout", &of_stdout_handle, + sizeof(of_stdout_handle)) + == sizeof(of_stdout_handle))) { + of_stdout_handle = be32_to_cpu(of_stdout_handle); + return 0; + } + + return -1; +} + +static void of_console_write(const char *buf, int len) +{ + of_call_prom("write", 3, 1, of_stdout_handle, buf, len); +} + +void of_console_init(void) +{ + console_ops.open = of_console_open; + console_ops.write = of_console_write; +} -- cgit v1.3.1