CVE-2026-72474dmaengine: dma-axi-dmac: use DMA pool to manange DMA descriptor

Official description

In the Linux kernel, the following vulnerability has been resolved: dmaengine: dma-axi-dmac: use DMA pool to manange DMA descriptor For architectures like Microblaze or arm64 (where this IP is used), DMA_DIRECT_REMAP is set which means that dma_alloc_coherent() might remap (and hence vmalloc()) some memory. This became visible in a design where dma_direct_use_pool() is not possible. With the above, when calling dma_free_coherent(), vunmap() would be called from softirq context and thus leading to a BUG(). To fix it, use a dma pool that is allocated in .device_alloc_chan_resources() and allocate blocks from it. The key point is that now dma_pool_free() is used in axi_dmac_free_desc() to free the blocks and that just frees the blocks from the pool in the sense they can be used again. In other words, no actual call to dma_free_coherent() happens. That only happens when destroying the pool in axi_dmac_free_chan_resources() which does not happen in any interrupt context.

Affected packages & fixed versions

Affected products (as reported)

References

• https://git.kernel.org/stable/c/a4f41ceecfe68e117bae9c76c5ebc5e2b353fa56
• https://git.kernel.org/stable/c/c0e6bb2b0408fcac6382158ee2bd9fdc45eceee9
• https://git.kernel.org/stable/c/65e82fa24965b2eb6ad9412f6c530ed9a50a625f
• https://git.kernel.org/stable/c/9e942c8579130e62734c14338e9f451780669164