[PATCH 6.6 337/396] nouveau/dmem: handle kcalloc() allocation failure

Greg Kroah-Hartman
2024-04-01T16:54:40Z

From: Duoming Zhou <duoming@zju.edu.cn>

commit 16e87fe23d4af6df920406494ced5c0f4354567b upstream.

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.

CC: <stable@vger.kernel.org> # v6.1
Fixes: 249881232e14 ("nouveau/dmem: evict device private memory during release")
Suggested-by: Danilo Krummrich <dakr@redhat.com>
Signed-off-by: Duoming Zhou <duoming@zju.edu.cn>
Signed-off-by: Danilo Krummrich <dakr@redhat.com>
Link: https://patchwork.freedesktop.org/patch/msgid/20240306050104.11259-1-duoming@zju.edu.cn
Signed-off-by: Greg Kroah-Hartman <gregkh@linuxfoundation.org>
---
drivers/gpu/drm/nouveau/nouveau_dmem.c | 12 ++++++------
1 file changed, 6 insertions(+), 6 deletions(-)

--- a/drivers/gpu/drm/nouveau/nouveau_dmem.c
+++ b/drivers/gpu/drm/nouveau/nouveau_dmem.c
@@ -378,9 +378,9 @@ nouveau_dmem_evict_chunk(struct nouveau_
dma_addr_t *dma_addrs;
struct nouveau_fence *fence;

- src_pfns = kcalloc(npages, sizeof(*src_pfns), GFP_KERNEL);
- dst_pfns = kcalloc(npages, sizeof(*dst_pfns), GFP_KERNEL);
- dma_addrs = kcalloc(npages, sizeof(*dma_addrs), GFP_KERNEL);
+ src_pfns = kvcalloc(npages, sizeof(*src_pfns), GFP_KERNEL | __GFP_NOFAIL);
+ dst_pfns = kvcalloc(npages, sizeof(*dst_pfns), GFP_KERNEL | __GFP_NOFAIL);
+ dma_addrs = kvcalloc(npages, sizeof(*dma_addrs), GFP_KERNEL | __GFP_NOFAIL);

migrate_device_range(src_pfns, chunk->pagemap.range.start >> PAGE_SHIFT,
npages);
@@ -406,11 +406,11 @@ nouveau_dmem_evict_chunk(struct nouveau_
migrate_device_pages(src_pfns, dst_pfns, npages);
nouveau_dmem_fence_done(&fence);
migrate_device_finalize(src_pfns, dst_pfns, npages);
- kfree(src_pfns);
- kfree(dst_pfns);
+ kvfree(src_pfns);
+ kvfree(dst_pfns);
for (i = 0; i < npages; i++)
dma_unmap_page(chunk->drm->dev->dev, dma_addrs[i], PAGE_SIZE, DMA_BIDIRECTIONAL);
- kfree(dma_addrs);
+ kvfree(dma_addrs);
}

void