nouveau/dmem: handle kcalloc() allocation failure

Vulnerability Description

In the Linux kernel, the following vulnerability has been resolved: nouveau/dmem: handle kcalloc() allocation failure The kcalloc() in nouveau_dmem_evict_chunk() will return null if the physical memory has run out. As a result, if we dereference src_pfns, dst_pfns or dma_addrs, the null pointer dereference bugs will happen. Moreover, the GPU is going away. If the kcalloc() fails, we could not evict all pages mapping a chunk. So this patch adds a __GFP_NOFAIL flag in kcalloc(). Finally, as there is no need to have physically contiguous memory, this patch switches kcalloc() to kvcalloc() in order to avoid failing allocations.

References

• https://git.kernel.org/stable/c/9acfd8b083a0ffbd387566800d89f55058a68af2
• https://git.kernel.org/stable/c/2a84744a037b8a511d6a9055f3defddc28ff4a4d
• https://git.kernel.org/stable/c/5e81773757a95fc298e96cfd6d4700f07b6192a2
• https://git.kernel.org/stable/c/3e82f7383e0b82a835e6b6b06a348b2bc4e2c2ee
• https://git.kernel.org/stable/c/16e87fe23d4af6df920406494ced5c0f4354567b