On Mon, Jan 19, 2026 at 11:39:51AM +0100, David Hildenbrand (Red Hat) wrote: > On > > $ uname -r > 6.18.4-200.fc43.x86_64 > > I am getting > > $ ./va_high_addr_switch > mmap(addr_switch_hint - pagesize, pagesize): 0x7fe7de6d7000 - OK > mmap(addr_switch_hint - pagesize, (2 * pagesize)): 0x7fe7de6d6000 - OK > mmap(addr_switch_hint, pagesize): 0x7fe7de6d7000 - OK > mmap(addr_switch_hint, 2 * pagesize, MAP_FIXED): 0xffffffffffffffff - FAILED > mmap(NULL): 0x7fe7de6d5000 - OK > mmap(low_addr): 0x40000000 - OK > mmap(high_addr): 0x7fe7de6d5000 - OK > mmap(high_addr) again: 0x7fe7de6d3000 - OK > mmap(high_addr, MAP_FIXED): 0xffffffffffffffff - FAILED > mmap(-1): 0x7fe7de6d1000 - OK > mmap(-1) again: 0x7fe7de6cf000 - OK > mmap(addr_switch_hint - pagesize, pagesize): 0x7fe7de6d0000 - OK > mmap(addr_switch_hint - pagesize, 2 * pagesize): 0x7fe7de6cf000 - OK > mmap(addr_switch_hint - pagesize/2 , 2 * pagesize): 0x7fe7de6cd000 - OK > mmap(addr_switch_hint, pagesize): 0x7fe7de6cc000 - OK > mmap(addr_switch_hint, 2 * pagesize, MAP_FIXED): 0xffffffffffffffff - FAILED > > > Are these the same issues you see?
No, that's entirely separate bug it seems :) Seems to work locally for me on 6.18.3, and also in VM with tip mm-unstable, strange. The issue here is with virtual_address_space.c which seems to just to be generally broken, I couldn't even bisect to a working one, and I really did try. Actually hang on, isn't va_high_addr_space already then testing what virtual_address_space should be testing anyway if it were sensible?? That suggests then that just removing virtual_address_space without replacement (since this already exists) is the right way (...!) Thanks, Lorenzo
