A test program from the rr[0] test suite, vm_readv_writev[1], no longer works on 5.10-rc1 when compiled as a 32 bit binary and executed on a 64 bit kernel. The first process_vm_readv call (on line 35) now fails with EFAULT. I have bisected this to c3973b401ef2b0b8005f8074a10e96e3ea093823. It should be fairly straightforward to extract the test case from our repository into a standalone program. - Kyle [0] https://rr-project.org/ [1] https://github.com/mozilla/rr/blob/master/src/test/vm_readv_writev.c