On 1/19/26 12:06, Lorenzo Stoakes wrote:
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 :)
Oh, lol, I ran the wrong test.
Yes, on Fedora config I just get
$ ./virtual_address_range
TAP version 13
1..1
ok 1 # SKIP prctl(PR_SET_VMA_ANON_NAME) not supported
# 1 skipped test(s) detected. Consider enabling relevant config options
to improve coverage.
# Totals: pass:0 fail:0 xfail:0 xpass:0 skip:1 error:0
Seems to work locally for me on 6.18.3, and also in VM with tip mm-unstable,
strange.
Maybe a hardware thing (notebook not supporting 5 level page tables, maybe?)
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 (...!)
I cannot really judge, I would have to decipher the details of the tests ...
--
Cheers
David
