CyberRota Analysis
AI-GeneratedThe vulnerability in the Linux kernel affects the DMA engine for architectures like Microblaze and arm64, where improper handling of DMA descriptors can lead to a potential crash due to a BUG() being triggered in softirq context. This issue arises when dma_free_coherent() is called without proper management of memory allocation, potentially compromising system stability. Organizations utilizing affected Linux kernel versions on these architectures should prioritize patching this vulnerability to ensure system reliability and prevent unexpected crashes.
Original NVD 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.