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/dma/dw/acpi.c | 57 +++++++++++++++++++++++++++++++++++++++++++++++++++ 1 file changed, 57 insertions(+) create mode 100644 drivers/dma/dw/acpi.c (limited to 'drivers/dma/dw/acpi.c') diff --git a/drivers/dma/dw/acpi.c b/drivers/dma/dw/acpi.c new file mode 100644 index 000000000..b6452fffa --- /dev/null +++ b/drivers/dma/dw/acpi.c @@ -0,0 +1,57 @@ +// SPDX-License-Identifier: GPL-2.0 +// Copyright (C) 2013,2019 Intel Corporation + +#include +#include + +#include "internal.h" + +static bool dw_dma_acpi_filter(struct dma_chan *chan, void *param) +{ + struct dw_dma *dw = to_dw_dma(chan->device); + struct dw_dma_chip_pdata *data = dev_get_drvdata(dw->dma.dev); + struct acpi_dma_spec *dma_spec = param; + struct dw_dma_slave slave = { + .dma_dev = dma_spec->dev, + .src_id = dma_spec->slave_id, + .dst_id = dma_spec->slave_id, + .m_master = data->m_master, + .p_master = data->p_master, + }; + + return dw_dma_filter(chan, &slave); +} + +void dw_dma_acpi_controller_register(struct dw_dma *dw) +{ + struct device *dev = dw->dma.dev; + struct acpi_dma_filter_info *info; + int ret; + + if (!has_acpi_companion(dev)) + return; + + info = devm_kzalloc(dev, sizeof(*info), GFP_KERNEL); + if (!info) + return; + + dma_cap_zero(info->dma_cap); + dma_cap_set(DMA_SLAVE, info->dma_cap); + info->filter_fn = dw_dma_acpi_filter; + + ret = acpi_dma_controller_register(dev, acpi_dma_simple_xlate, info); + if (ret) + dev_err(dev, "could not register acpi_dma_controller\n"); +} +EXPORT_SYMBOL_GPL(dw_dma_acpi_controller_register); + +void dw_dma_acpi_controller_free(struct dw_dma *dw) +{ + struct device *dev = dw->dma.dev; + + if (!has_acpi_companion(dev)) + return; + + acpi_dma_controller_free(dev); +} +EXPORT_SYMBOL_GPL(dw_dma_acpi_controller_free); -- cgit v1.3.1