Messages in this thread | | | Date | Sun, 19 Aug 2018 08:57:31 -0400 | Subject | Re: [PATCH] swiotlb: Fix uninitialized pointer on DMA ops | From | Konrad Rzeszutek Wilk <> |
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On August 18, 2018 3:04:51 PM EDT, Esteban Zamora <estebanzacr.20@gmail.com> wrote: >The mmap function pointer on swiotlb_dma_ops struct is >uninitialized, which causes a random crash when calling >the dma_mmap_coherent function on platforms where no DMA >address translation hardware is available. > >Set this pointer to NULL in order to fix the issue.
By default unused entries in .rodata structure (like this one) are zero - meaning they are NULL if not set by the complier.
You should be able to verify this by looking at the objdump of the kernel and find this structure.
> >Signed-off-by: Esteban Zamora <estebanzacr.20@gmail.com> >--- > kernel/dma/swiotlb.c | 1 + > 1 file changed, 1 insertion(+) > >diff --git a/kernel/dma/swiotlb.c b/kernel/dma/swiotlb.c >index 4f8a6db..9a7718c 100644 >--- a/kernel/dma/swiotlb.c >+++ b/kernel/dma/swiotlb.c >@@ -1082,5 +1082,6 @@ const struct dma_map_ops swiotlb_dma_ops = { > .map_page = swiotlb_map_page, > .unmap_page = swiotlb_unmap_page, > .dma_supported = dma_direct_supported, >+ .mmap = NULL, > }; > EXPORT_SYMBOL(swiotlb_dma_ops);
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