Re: vmsplice returned "bad address"

On Fri, 19 Aug 2016 00:19:47 +0800, Teoh Choon Zone said:

I have a driver which will dma_alloc a CMA region and return the address to my user space program, the program then will mmap /dev/mem according to the address offset.

Step 1: Figure out whether your driver is returning a physical or logical address for the CMA, and which of the two /dev/mem requires. Step 2: Take a look at the address returned and make sure it at least looks valid (is someplace the E820 map says is RAM, isn't a PCI BAR or something like that, etc etc) Those are the two biggest sources of error I can think of...