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

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 <[email protected]> Signed-off-by: Martin Schwidefsky <[email protected]>
farmergreg · May 16, 2012 · a686425 · a686425
1 parent 5e8010c
commit a686425
Showing 1 changed file with 2 additions and 0 deletions.
diff --git a/arch/s390/mm/hugetlbpage.c b/arch/s390/mm/hugetlbpage.c
@@ -58,6 +58,8 @@ void arch_release_hugepage(struct page *page)
 	ptep = (pte_t *) page[1].index;
 	if (!ptep)
 		return;
+	clear_table((unsigned long *) ptep, _PAGE_TYPE_EMPTY,
+		    PTRS_PER_PTE * sizeof(pte_t));
 	page_table_free(&init_mm, (unsigned long *) ptep);
 	page[1].index = 0;
 }