github-mirror/linux
1
0
Fork 0
mirror of https://github.com/torvalds/linux.git synced 2026-07-27 17:47:41 +02:00
Code Issues Actions Packages Projects Releases Wiki Activity Graph

selftest/mm: register existing mapping with userfaultfd in hugetlb-mremap

Browse Source 
Previously, register_region_with_uffd() created a new anonymous mapping
and overwrote the address supplied by the caller before registering the
range with userfaultfd.

As a result, userfaultfd was applied to an unrelated anonymous mapping
instead of the hugetlb region used by the test.

Remove the extra mmap() and register the caller-provided address range
directly using UFFDIO_REGISTER_MODE_MISSING, so that faults are generated
for the hugetlb mapping used by the test.

This ensures userfaultfd operates on the actual hugetlb test region and
validates the expected fault handling.

Before patch:
 running ./hugetlb-mremap
 -------------------------
 TAP version 13
 1..1
  Map haddr: Returned address is 0x7eaa40000000
  Map daddr: Returned address is 0x7daa40000000
  Map vaddr: Returned address is 0x7faa40000000
  Address returned by mmap() = 0x7fff9d000000
  Mremap: Returned address is 0x7faa40000000
  First hex is 0
  First hex is 3020100
 ok 1 Read same data
 Totals: pass:1 fail:0 xfail:0 xpass:0 skip:0 error:0
 [PASS]
 ok 1 hugetlb-mremap

After patch:
 running ./hugetb-mremap
 -------------------------
 TAP version 13
 1..1
  Map haddr: Returned address is 0x7eaa40000000
  Map daddr: Returned address is 0x7daa40000000
  Map vaddr: Returned address is 0x7faa40000000
  Registered memory at address 0x7eaa40000000 with userfaultfd
  Mremap: Returned address is 0x7faa40000000
  First hex is 0
  First hex is 3020100
 ok 1 Read same data
 Totals: pass:1 fail:0 xfail:0 xpass:0 skip:0 error:0
 [PASS]
 ok 1 hugetlb-mremap

Link: https://lore.kernel.org/13845da872ed174316173e8996dbb5f181994017.1779296493.git.sayalip@linux.ibm.com
Fixes: 12b6132064 ("mm, hugepages: add hugetlb vma mremap() test")
Signed-off-by: Sayali Patil <sayalip@linux.ibm.com>
Acked-by: David Hildenbrand (Arm) <david@kernel.org>
Tested-by: Venkat Rao Bagalkote <venkat88@linux.ibm.com>
Cc: Dev Jain <dev.jain@arm.com>
Cc: Liam Howlett <liam.howlett@oracle.com>
Cc: Miaohe Lin <linmiaohe@huawei.com>
Cc: Michal Hocko <mhocko@kernel.org>
Cc: Oscar Salvador <osalvador@suse.de>
Cc: "Ritesh Harjani (IBM)" <ritesh.list@gmail.com>
Cc: Shuah Khan <shuah@kernel.org>
Cc: Zi Yan <ziy@nvidia.com>
Signed-off-by: Andrew Morton <akpm@linux-foundation.org>
This commit is contained in:
Sayali Patil 2026-05-21 12:17:48 +05:30 committed by Andrew Morton
parent e5d3e1422e
commit 1df31d5ef5
1 changed files with 5 additions and 16 deletions
Show Stats Download Patch File Download Diff File Expand all files Collapse all files

21
tools/testing/selftests/mm/hugetlb-mremap.c
View File

@ -86,25 +86,14 @@ static void register_region_with_uffd(char *addr, size_t len)
if (ioctl(uffd, UFFDIO_API, &uffdio_api) == -1)
ksft_exit_fail_msg("ioctl-UFFDIO_API: %s\n", strerror(errno));
/* Create a private anonymous mapping. The memory will be
* demand-zero paged--that is, not yet allocated. When we
* actually touch the memory, it will be allocated via
* the userfaultfd.
*/
addr = mmap(NULL, len, PROT_READ | PROT_WRITE,
MAP_PRIVATE | MAP_ANONYMOUS, -1, 0);
if (addr == MAP_FAILED)
ksft_exit_fail_msg("mmap: %s\n", strerror(errno));
ksft_print_msg("Address returned by mmap() = %p\n", addr);
/* Register the memory range of the mapping we just created for
* handling by the userfaultfd object. In mode, we request to track
* missing pages (i.e., pages that have not yet been faulted in).
/* Register the passed memory range for handling by the userfaultfd object.
* In mode, we request to track missing pages
* (i.e., pages that have not yet been faulted in).
*/
if (uffd_register(uffd, addr, len, true, false, false))
ksft_exit_fail_msg("ioctl-UFFDIO_REGISTER: %s\n", strerror(errno));
ksft_print_msg("Registered memory at address %p with userfaultfd\n", addr);
}
int main(int argc, char *argv[])