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c56325259a
linux/tools/testing
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Chunyu Hu c56325259a selftests/mm: fix va_high_addr_switch.sh failure on x86_64 
The test will fail as below on x86_64 with cpu la57 support (will skip if
no la57 support).  Note, the test requries nr_hugepages to be set first.

  # running bash ./va_high_addr_switch.sh
  # -------------------------------------
  # mmap(addr_switch_hint - pagesize, pagesize): 0x7f55b60fa000 - OK
  # mmap(addr_switch_hint - pagesize, (2 * pagesize)): 0x7f55b60f9000 - OK
  # mmap(addr_switch_hint, pagesize): 0x800000000000 - OK
  # mmap(addr_switch_hint, 2 * pagesize, MAP_FIXED): 0x800000000000 - OK
  # mmap(NULL): 0x7f55b60f9000 - OK
  # mmap(low_addr): 0x40000000 - OK
  # mmap(high_addr): 0x1000000000000 - OK
  # mmap(high_addr) again: 0xffff55b6136000 - OK
  # mmap(high_addr, MAP_FIXED): 0x1000000000000 - OK
  # mmap(-1): 0xffff55b6134000 - OK
  # mmap(-1) again: 0xffff55b6132000 - OK
  # mmap(addr_switch_hint - pagesize, pagesize): 0x7f55b60fa000 - OK
  # mmap(addr_switch_hint - pagesize, 2 * pagesize): 0x7f55b60f9000 - OK
  # mmap(addr_switch_hint - pagesize/2 , 2 * pagesize): 0x7f55b60f7000 - OK
  # mmap(addr_switch_hint, pagesize): 0x800000000000 - OK
  # mmap(addr_switch_hint, 2 * pagesize, MAP_FIXED): 0x800000000000 - OK
  # mmap(NULL, MAP_HUGETLB): 0x7f55b5c00000 - OK
  # mmap(low_addr, MAP_HUGETLB): 0x40000000 - OK
  # mmap(high_addr, MAP_HUGETLB): 0x1000000000000 - OK
  # mmap(high_addr, MAP_HUGETLB) again: 0xffff55b5e00000 - OK
  # mmap(high_addr, MAP_FIXED | MAP_HUGETLB): 0x1000000000000 - OK
  # mmap(-1, MAP_HUGETLB): 0x7f55b5c00000 - OK
  # mmap(-1, MAP_HUGETLB) again: 0x7f55b5a00000 - OK
  # mmap(addr_switch_hint - pagesize, 2*hugepagesize, MAP_HUGETLB): 0x800000000000 - FAILED
  # mmap(addr_switch_hint , 2*hugepagesize, MAP_FIXED | MAP_HUGETLB): 0x800000000000 - OK
  # [FAIL]

addr_switch_hint is defined as DFEFAULT_MAP_WINDOW in the failed test (for
x86_64, DFEFAULT_MAP_WINDOW is defined as (1UL<<47) - pagesize) in 64 bit.

Before commit cc92882ee2 ("mm: drop hugetlb_get_unmapped_area{_*}
functions"), for x86_64 hugetlb_get_unmapped_area() is handled in arch
code arch/x86/mm/hugetlbpage.c and addr is checked with
map_address_hint_valid() after align with 'addr &= huge_page_mask(h)'
which is a round down way, and it will fail the check because the addr is
within the DEFAULT_MAP_WINDOW but (addr + len) is above the
DFEFAULT_MAP_WINDOW.  So it wil go through the
hugetlb_get_unmmaped_area_top_down() to find an area within the
DFEFAULT_MAP_WINDOW.

After commit cc92882ee2 ("mm: drop hugetlb_get_unmapped_area{_*}
functions").  The addr hint for hugetlb_get_unmmaped_area() will be
rounded up and aligned to hugepage size with ALIGN() for all arches.  And
after the align, the addr will be above the default MAP_DEFAULT_WINDOW,
and the map_addresshint_valid() check will pass because both aligned addr
(addr0) and (addr + len) are above the DEFAULT_MAP_WINDOW, and the aligned
hint address (0x800000000000) is returned as an suitable gap is found
there, in arch_get_unmapped_area_topdown().

To still cover the case that addr is within the DEFAULT_MAP_WINDOW, and
addr + len is above the DFEFAULT_MAP_WINDOW, change to choose the last
hugepage aligned address within the DEFAULT_MAP_WINDOW as the hint addr,
and the addr + len (2 hugepages) will be one hugepage above the
DEFAULT_MAP_WINDOW.  An aligned address won't be affected by the page
round up or round down from kernel, so it's determistic.

Link: https://lkml.kernel.org/r/20250912013711.3002969-4-chuhu@redhat.com
Fixes: cc92882ee2 ("mm: drop hugetlb_get_unmapped_area{_*} functions")
Signed-off-by: Chunyu Hu <chuhu@redhat.com>
Suggested-by: David Hildenbrand <david@redhat.com>
Acked-by: David Hildenbrand <david@redhat.com>
Signed-off-by: Andrew Morton <akpm@linux-foundation.org>
2025-09-21 14:22:29 -07:00
..
crypto/chacha20-s390
cxl cxl for v6.17 2025-08-01 15:47:06 -07:00
fault-injection
ktest ktest.pl: Add new PATCHCHECK_SKIP option to skip testing individual commits 2025-07-29 09:30:08 -04:00
kunit Revert "kunit: configs: Enable CONFIG_INIT_STACK_ALL_PATTERN in all_tests" 2025-06-03 11:20:21 +02:00
memblock
nvdimm mm: remove callers of pfn_t functionality 2025-07-09 22:42:19 -07:00
radix-tree maple_tree: testing fix for spanning store on 32b 2025-09-13 16:55:26 -07:00
rbtree
scatterlist mm: remove nth_page() 2025-09-21 14:22:10 -07:00
selftests selftests/mm: fix va_high_addr_switch.sh failure on x86_64 2025-09-21 14:22:29 -07:00
shared tools: testing: use existing atomic.h for vma/maple tests 2025-09-13 16:55:25 -07:00
vma tools: testing: use existing atomic.h for vma/maple tests 2025-09-13 16:55:25 -07:00
vsock vsock/test: fix vsock_ioctl_int() check for unsupported ioctl 2025-07-16 16:14:00 -07:00