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/acpi/arm64/dma.c | 52 ++++++++++++++++++++++++++++++++++++++++++++++++ 1 file changed, 52 insertions(+) create mode 100644 drivers/acpi/arm64/dma.c (limited to 'drivers/acpi/arm64/dma.c') diff --git a/drivers/acpi/arm64/dma.c b/drivers/acpi/arm64/dma.c new file mode 100644 index 000000000..f30f13835 --- /dev/null +++ b/drivers/acpi/arm64/dma.c @@ -0,0 +1,52 @@ +// SPDX-License-Identifier: GPL-2.0-only +#include +#include +#include +#include + +void acpi_arch_dma_setup(struct device *dev) +{ + int ret; + u64 end, mask; + const struct bus_dma_region *map = NULL; + + /* + * If @dev is expected to be DMA-capable then the bus code that created + * it should have initialised its dma_mask pointer by this point. For + * now, we'll continue the legacy behaviour of coercing it to the + * coherent mask if not, but we'll no longer do so quietly. + */ + if (!dev->dma_mask) { + dev_warn(dev, "DMA mask not set\n"); + dev->dma_mask = &dev->coherent_dma_mask; + } + + if (dev->coherent_dma_mask) + end = dev->coherent_dma_mask; + else + end = (1ULL << 32) - 1; + + if (dev->dma_range_map) { + dev_dbg(dev, "dma_range_map already set\n"); + return; + } + + ret = acpi_dma_get_range(dev, &map); + if (!ret && map) { + end = dma_range_map_max(map); + dev->dma_range_map = map; + } + + if (ret == -ENODEV) + ret = iort_dma_get_ranges(dev, &end); + if (!ret) { + /* + * Limit coherent and dma mask based on size retrieved from + * firmware. + */ + mask = DMA_BIT_MASK(ilog2(end) + 1); + dev->bus_dma_limit = end; + dev->coherent_dma_mask = min(dev->coherent_dma_mask, mask); + *dev->dma_mask = min(*dev->dma_mask, mask); + } +} -- cgit v1.3.1