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/nvmem/uniphier-efuse.c | 77 ++++++++++++++++++++++++++++++++++++++++++ 1 file changed, 77 insertions(+) create mode 100644 drivers/nvmem/uniphier-efuse.c (limited to 'drivers/nvmem/uniphier-efuse.c') diff --git a/drivers/nvmem/uniphier-efuse.c b/drivers/nvmem/uniphier-efuse.c new file mode 100644 index 000000000..85f9372fb --- /dev/null +++ b/drivers/nvmem/uniphier-efuse.c @@ -0,0 +1,77 @@ +// SPDX-License-Identifier: GPL-2.0-only +/* + * UniPhier eFuse driver + * + * Copyright (C) 2017 Socionext Inc. + */ + +#include +#include +#include +#include +#include + +struct uniphier_efuse_priv { + void __iomem *base; +}; + +static int uniphier_reg_read(void *context, + unsigned int reg, void *_val, size_t bytes) +{ + struct uniphier_efuse_priv *priv = context; + u8 *val = _val; + int offs; + + for (offs = 0; offs < bytes; offs += sizeof(u8)) + *val++ = readb(priv->base + reg + offs); + + return 0; +} + +static int uniphier_efuse_probe(struct platform_device *pdev) +{ + struct device *dev = &pdev->dev; + struct resource *res; + struct nvmem_device *nvmem; + struct nvmem_config econfig = {}; + struct uniphier_efuse_priv *priv; + + priv = devm_kzalloc(dev, sizeof(*priv), GFP_KERNEL); + if (!priv) + return -ENOMEM; + + priv->base = devm_platform_get_and_ioremap_resource(pdev, 0, &res); + if (IS_ERR(priv->base)) + return PTR_ERR(priv->base); + + econfig.stride = 1; + econfig.word_size = 1; + econfig.read_only = true; + econfig.reg_read = uniphier_reg_read; + econfig.size = resource_size(res); + econfig.priv = priv; + econfig.dev = dev; + econfig.add_legacy_fixed_of_cells = true; + nvmem = devm_nvmem_register(dev, &econfig); + + return PTR_ERR_OR_ZERO(nvmem); +} + +static const struct of_device_id uniphier_efuse_of_match[] = { + { .compatible = "socionext,uniphier-efuse",}, + {/* sentinel */}, +}; +MODULE_DEVICE_TABLE(of, uniphier_efuse_of_match); + +static struct platform_driver uniphier_efuse_driver = { + .probe = uniphier_efuse_probe, + .driver = { + .name = "uniphier-efuse", + .of_match_table = uniphier_efuse_of_match, + }, +}; +module_platform_driver(uniphier_efuse_driver); + +MODULE_AUTHOR("Keiji Hayashibara "); +MODULE_DESCRIPTION("UniPhier eFuse driver"); +MODULE_LICENSE("GPL v2"); -- cgit v1.3.1