On Mon, Jul 20, 2020 at 10:30:30PM -0700, Guenter Roeck wrote: > Guess I lost it somewhere. Are you saying the check was wrong all along > and your patch fixed it ? Oh, it is a little complicated. Normally we have two address space limits, KERNEL_DS and USER_DS, and they are supposed to be different. armnommu and m68k define them to the same value for no good reason. That leads to: uaccess_kernel always returning true as it does a positive check agains KERNEL_DS, which disables a bunch of drivers like sg and rdma, and could also lead to really strange and probably broken results in a few places. It also leads to the SIGKILL in addr_limit_user_check never triggering due to the negatіve check, which is ok as the limits never are different.
