Messages in this thread | | | Date | Tue, 15 Sep 2020 16:07:19 +0200 | From | Christoph Hellwig <> | Subject | Re: [PATCH] dma-direct: Fix potential NULL pointer dereference |
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On Tue, Sep 15, 2020 at 08:03:14AM -0600, Thomas Tai wrote: > When booting the kernel v5.9-rc4 on a VM, the kernel would panic when > printing a warning message in swiotlb_map(). It is because dev->dma_mask > can potentially be a null pointer. Using the dma_get_mask() macro can > avoid the NULL pointer dereference.
dma_mask must not be zero. This means drm is calling DMA API functions on something weird. This needs to be fixed in the caller.
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