swiotlb: Preserve allocation virtual address for dynamic pools

Summary

In the Linux kernel, the following vulnerability has been resolved: swiotlb: Preserve allocation virtual address for dynamic pools swiotlb_alloc_tlb() can allocate from the DMA atomic pool when a decrypted pool is needed from atomic context. With CONFIG_DMA_DIRECT_REMAP, the atomic pool is backed by remapped virtual addresses, which are not the same as the direct-map addresses returned by phys_to_virt(). swiotlb_init_io_tlb_pool() currently reconstructs the pool virtual address from the physical start address. For atomic-pool backed allocations this stores the wrong address in pool->vaddr. Later, swiotlb_free_tlb() passes that address to dma_free_from_pool(), which will fail to recognize the chunk Pass the virtual address returned by the allocation path into swiotlb_init_io_tlb_pool(), and store that address in pool->vaddr. This keeps the pool free path using the same virtual address as the allocator.

Timeline

1. Sep 17, 2026, 4:09 PM UTCCVE published
2. Oct 19, 2026, 9:02 AM UTCRecord last updated

Affected versions

• Linux Linux

  From 79636caad3618e2b38457f6e298c9b31ba82b489 · fixed in 68bf3ebd8e7020dae58e8aa14c7d482738bff9a8; From 79636caad3618e2b38457f6e298c9b31ba82b489 · fixed in 45507dcb0847e96add4455274b12df0eca6590b4; From 79636caad3618e2b38457f6e298c9b31ba82b489 · fixed in 35e0103177826430b5df888b1506239d41e76ab5; From 79636caad3618e2b38457f6e298c9b31ba82b489 · fixed in c1f4d7763cdf1b9e0d35c14aa6f52d0512a36319; From 79636caad3618e2b38457f6e298c9b31ba82b489 · fixed in 57d29044d0f29a76c6ec0c112c8c7371d5608dc7

• Linux Linux

  6.6

• KernelLinux

  From 6.6.0 · fixed in 6.6.157; From 6.7.0 · fixed in 6.12.110; From 6.13.0 · fixed in 6.18.52; From 6.19.0 · fixed in 7.2.6

References 5