As we've seen from USB and other areas[1], we need to always do runtime checks for DMA operating on memory regions that might be remapped. This adds vmap checks (similar to those already in USB but missing in other places) into dma_map_single() so all callers benefit from the checking. [1] https://git.kernel.org/linus/3840c5b78803b2b6cc1ff820100a74a092c40cbb
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| @@ -583,6 +583,10 @@ static inline unsigned long dma_get_merge_boundary(struct device *dev) · 582 unmodified lines | ||
| 583 | 583 | static inline dma_addr_t dma_map_single_attrs(struct device *dev, void *ptr, |
| 584 | 584 | size_t size, enum dma_data_direction dir, unsigned long attrs) |
| 585 | 585 | { |
| 586 | + /* DMA must never operate on areas that might be remapped. */ | |
| 587 | + if (dev_WARN_ONCE(dev, is_vmalloc_addr(ptr), | |
| 588 | + "rejecting DMA map of vmalloc memory\n")) | |
| 589 | + return DMA_MAPPING_ERROR; | |
| 586 | 590 | debug_dma_map_single(dev, ptr, size); |
| 587 | 591 | return dma_map_page_attrs(dev, virt_to_page(ptr), offset_in_page(ptr), |
| 588 | 592 | size, dir, attrs); |