On Tue, Aug 27, 2019 at 11:28:20AM +0300, Gal Pressman wrote: > On 26/08/2019 17:05, Gal Pressman wrote: > > Hi all, > > > > Lately I've been seeing DMA-API call traces on our automated testing runs which > > complain about overlapping mappings of the same cacheline [1]. > > The problem is (most likely) caused due to multiple calls to ibv_reg_mr with the > > same address, which as a result DMA maps the same physical addresses more than 7 > > (ACTIVE_CACHELINE_MAX_OVERLAP) times. > > BTW, on rare occasions I'm seeing the boundary check in check_sg_segment [1] > fail as well. I don't have a stable repro for it though. > > Is this a known issue as well? The comment there states it might be a bug in the > DMA API implementation, but I'm not sure. > > [1] https://elixir.bootlin.com/linux/v5.3-rc3/source/kernel/dma/debug.c#L1230 Maybe we are missing a dma_set_seg_boundary ? PCI uses low defaults: dma_set_max_seg_size(&dev->dev, 65536); dma_set_seg_boundary(&dev->dev, 0xffffffff); Jason
