tree 6fe815d5482651933f6b31201ef912358fb1b8f7
parent 023217c5e7f396c44e71b9e4674c932d78a00cc3
author Naoya Horiguchi <n-horiguchi@ah.jp.nec.com> 1387354962 -0500
committer Chen, Gong <gong.chen@linux.intel.com> 1387355200 -0500

Add test case 'hugepage_overcommit'

After a successful hugetlb page migration by soft offline, the source
page will either be freed into hugepage_freelists or buddy
(over-commit page). If page is in buddy, page_hstate(page) will be
NULL. It will hit a NULL pointer dereference in
dequeue_hwpoisoned_huge_page().

[  890.677918] BUG: unable to handle kernel NULL pointer dereference at 0000000000000058
[  890.685741] IP: [<ffffffff81163761>] dequeue_hwpoisoned_huge_page+0x131/0x1d0
[  890.692861] PGD c23762067 PUD c24be2067 PMD 0
[  890.697314] Oops: 0000 [#1] SMP

This test case is targeted for the bug reported by Jianguo Wu,
where we have NULL pointer access when we have to free source
hugepage under overcommitting situation.

Signed-off-by: Naoya Horiguchi <n-horiguchi@ah.jp.nec.com>
Signed-off-by: Chen, Gong <gong.chen@linux.intel.com>