tree b491fece3adcf231f597b9451a4153b5cfb391aa
parent 5a9e22cad70e803fe7e6aac7e059dce2cacf5427
author Tarun Sahu <tsahu@linux.ibm.com> 1671517867 +0530
committer Richard Palethorpe <rpalethorpe@suse.com> 1671537773 +0000

Hugetlb: Migrating libhugetlbfs map_high_truncate_2

Migrating the libhugetlbfs/testcases/map_high_truncate_2.c test

Test Description: At one stage, a misconversion of hugetlb_vmtruncate_list
to a prio_tree meant that on 32-bit machines, certain combinations of
mapping and truncations could truncate incorrect pages, or
overwrite pmds from other VMAs, triggering BUG_ON()s or other
wierdness.

Test adapted from an example by Kenneth Chen <kenneth.w.chen@intel.com>

WARNING: The offsets and addresses used within are specifically
calculated to trigger the bug as it existed.  Don't mess with them
unless you *really* know what you're doing.

The kernel bug in question was fixed with
'commit 856fc2950555 ("[PATCH] hugetlb: fix prio_tree unit")'.

Signed-off-by: Tarun Sahu <tsahu@linux.ibm.com>
Reviewed-by: Richard Palethorpe <rpalethorpe@suse.com>