Cc: netdev On Fri, Jun 14, 2013 at 9:38 PM, Jussi Kivilinna <jussi.kivilinna@xxxxxx> wrote: > Appearently some out-of-tree USB host drivers do not handle DMA alignment for Looks these host drivers have to face the fact that the transfer buffer is often DMA non-aligned from network device drivers(in fact, the buffer is from network protocol stack), if you run usbnet, then you will get the added warning immediately. > URB buffers and let core/hcd.c to do the mapping on architectures that have > minimum DMA alignment requirements. This leads to random memory corruptions > and crashes when using USB device drivers that use unaligned URB buffers. Maybe you should check the dma mapping/unmapping implementation of the arch, non-aligned buffer should have be covered by the API easily. Also USB Host controller should have supported non-aligned DMA buffer. > > Instead of fixing host drivers, users end up posting bug reports against > those USB device drivers that use unaligned buffers for URB; such as with > rtl8192cu (http://thread.gmane.org/gmane.linux.kernel.wireless.general/105631). Not only rtl8192cu driver, all USB network device drivers have the problem. > > Patch makes this issue more visible at core level, and hopefully gives hint > for future hcd driver implementors about this problem. So please find the root cause first, and don't add the noise now. Thanks, -- Ming Lei -- 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
