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/base/platform-msi.c | 96 +++++++++++++++++++++++++++++++++++++++++++++ 1 file changed, 96 insertions(+) create mode 100644 drivers/base/platform-msi.c (limited to 'drivers/base/platform-msi.c') diff --git a/drivers/base/platform-msi.c b/drivers/base/platform-msi.c new file mode 100644 index 000000000..69eed058e --- /dev/null +++ b/drivers/base/platform-msi.c @@ -0,0 +1,96 @@ +// SPDX-License-Identifier: GPL-2.0 +/* + * MSI framework for platform devices + * + * Copyright (C) 2015 ARM Limited, All Rights Reserved. + * Author: Marc Zyngier + * Copyright (C) 2022 Linutronix GmbH + */ + +#include +#include +#include + +/* + * This indirection can go when platform_device_msi_init_and_alloc_irqs() + * is switched to a proper irq_chip::irq_write_msi_msg() callback. Keep it + * simple for now. + */ +static void platform_msi_write_msi_msg(struct irq_data *d, struct msi_msg *msg) +{ + irq_write_msi_msg_t cb = d->chip_data; + + cb(irq_data_get_msi_desc(d), msg); +} + +static void platform_msi_set_desc(msi_alloc_info_t *arg, struct msi_desc *desc) +{ + arg->desc = desc; + arg->hwirq = desc->msi_index; +} + +static const struct msi_domain_template platform_msi_template = { + .chip = { + .name = "pMSI", + .irq_mask = irq_chip_mask_parent, + .irq_unmask = irq_chip_unmask_parent, + .irq_write_msi_msg = platform_msi_write_msi_msg, + /* The rest is filled in by the platform MSI parent */ + }, + + .ops = { + .set_desc = platform_msi_set_desc, + }, + + .info = { + .bus_token = DOMAIN_BUS_DEVICE_MSI, + }, +}; + +/** + * platform_device_msi_init_and_alloc_irqs - Initialize platform device MSI + * and allocate interrupts for @dev + * @dev: The device for which to allocate interrupts + * @nvec: The number of interrupts to allocate + * @write_msi_msg: Callback to write an interrupt message for @dev + * + * Returns: + * Zero for success, or an error code in case of failure + * + * This creates a MSI domain on @dev which has @dev->msi.domain as + * parent. The parent domain sets up the new domain. The domain has + * a fixed size of @nvec. The domain is managed by devres and will + * be removed when the device is removed. + */ +int platform_device_msi_init_and_alloc_irqs(struct device *dev, unsigned int nvec, + irq_write_msi_msg_t write_msi_msg) +{ + struct irq_domain *domain = dev->msi.domain; + + if (!domain || !write_msi_msg) + return -EINVAL; + + /* + * @write_msi_msg is stored in the resulting msi_domain_info::data. + * The underlying domain creation mechanism will assign that + * callback to the resulting irq chip. + */ + if (!msi_create_device_irq_domain(dev, MSI_DEFAULT_DOMAIN, + &platform_msi_template, + nvec, NULL, write_msi_msg)) + return -ENODEV; + + return msi_domain_alloc_irqs_range(dev, MSI_DEFAULT_DOMAIN, 0, nvec - 1); +} +EXPORT_SYMBOL_GPL(platform_device_msi_init_and_alloc_irqs); + +/** + * platform_device_msi_free_irqs_all - Free all interrupts for @dev + * @dev: The device for which to free interrupts + */ +void platform_device_msi_free_irqs_all(struct device *dev) +{ + msi_domain_free_irqs_all(dev, MSI_DEFAULT_DOMAIN); + msi_remove_device_irq_domain(dev, MSI_DEFAULT_DOMAIN); +} +EXPORT_SYMBOL_GPL(platform_device_msi_free_irqs_all); -- cgit v1.3.1