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s390/hugepages: clear page table for sw large page emulation

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The software large page emulation on s390 did not clear the the
pre-allocated page table in arch_release_hugepage() before freeing
it. This could trigger the WARN_ON(!pte_none(*pte) in mm/vmalloc.c:106
and make vmap_pte_range() fail, because the page table could be reused
in page_table_alloc(). This is fixed now by calling clear_table()
before page_table_free().

Signed-off-by: Gerald Schaefer <gerald.schaefer@de.ibm.com>
Signed-off-by: Martin Schwidefsky <schwidefsky@de.ibm.com>
This commit is contained in:
Gerald Schaefer 2012-05-09 16:27:37 +02:00 committed by Martin Schwidefsky
parent 5e8010cb50
commit a686425b31
1 changed files with 2 additions and 0 deletions
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arch/s390/mm/hugetlbpage.c
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@ -58,6 +58,8 @@ void arch_release_hugepage(struct page *page)
ptep = (pte_t *) page[1].index; ptep = (pte_t *) page[1].index;
if (!ptep) if (!ptep)
return; return;
clear_table((unsigned long *) ptep, _PAGE_TYPE_EMPTY,
PTRS_PER_PTE * sizeof(pte_t));
page_table_free(&init_mm, (unsigned long *) ptep); page_table_free(&init_mm, (unsigned long *) ptep);
page[1].index = 0; page[1].index = 0;
} }