On 09.08.2013 21:50, Petko Manolov wrote: > On Thu, 8 Aug 2013, Jussi Kivilinna wrote: > >> On 08.08.2013 18:14, Petko Manolov wrote: >>> On Wed, 7 Aug 2013, Jussi Kivilinna wrote: >>> >>>> rtl8150 allocates URB transfer_buffer and setup_packet as part of same >>>> structure 'struct async_req'. This can cause same cacheline to be >>>> DMA-mapped twice with same URB. This can lead to memory corruption on >>>> some systems. >>> >>> I can see performance impact due to the double mapping. However, memory >>> corruption seems a bit too much for sane cache and DMA controllers. Out >>> of interest - which is the architecture that will potentially corrupt the >>> memory. >> >> rtlwifi driver had similar structure to allocate both setup_packet and >> transfer_buffer in single go (overlapping dma-mapping cachelines) and >> this caused problems on ARM/sunxi. Problems means: memory corruptions at >> random locations, device freezes and lock-ups. > > Broken controllers?.. > At first I thought so too, but I discussed about this at linux-usb, and answer was that driver which uses same (dma/-)cacheline for multiple buffers is buggy.. http://marc.info/?l=linux-usb&m=137130407121137&w=2 (at end) http://marc.info/?l=linux-usb&m=137137080902265&w=2 http://marc.info/?l=linux-usb&m=137242422120782&w=2 -Jussi -- To unsubscribe from this list: send the line "unsubscribe linux-usb" in the body of a message to majordomo@xxxxxxxxxxxxxxx More majordomo info at http://vger.kernel.org/majordomo-info.html
