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 --- drivers/rtc/rtc-generic.c | 39 +++++++++++++++++++++++++++++++++++++++ 1 file changed, 39 insertions(+) create mode 100644 drivers/rtc/rtc-generic.c (limited to 'drivers/rtc/rtc-generic.c') diff --git a/drivers/rtc/rtc-generic.c b/drivers/rtc/rtc-generic.c new file mode 100644 index 000000000..89ae78e93 --- /dev/null +++ b/drivers/rtc/rtc-generic.c @@ -0,0 +1,39 @@ +// SPDX-License-Identifier: GPL-2.0-only +/* rtc-generic: RTC driver using the generic RTC abstraction + * + * Copyright (C) 2008 Kyle McMartin + */ + +#include +#include +#include +#include +#include + +static int __init generic_rtc_probe(struct platform_device *dev) +{ + struct rtc_device *rtc; + const struct rtc_class_ops *ops = dev_get_platdata(&dev->dev); + + rtc = devm_rtc_device_register(&dev->dev, "rtc-generic", + ops, THIS_MODULE); + if (IS_ERR(rtc)) + return PTR_ERR(rtc); + + platform_set_drvdata(dev, rtc); + + return 0; +} + +static struct platform_driver generic_rtc_driver = { + .driver = { + .name = "rtc-generic", + }, +}; + +module_platform_driver_probe(generic_rtc_driver, generic_rtc_probe); + +MODULE_AUTHOR("Kyle McMartin "); +MODULE_LICENSE("GPL"); +MODULE_DESCRIPTION("Generic RTC driver"); +MODULE_ALIAS("platform:rtc-generic"); -- cgit v1.3.1