From: Li Zhong <[email protected]> Subject: mm: fix potential infinite loop in dissolve_free_huge_pages()
It is possible for some platforms, such as powerpc to set HPAGE_SHIFT to 0 to indicate huge pages not supported. When this is the case, hugetlbfs could be disabled during boot time: hugetlbfs: disabling because there are no supported hugepage sizes Then in dissolve_free_huge_pages(), order is kept maximum (64 for 64bits), and the for loop below won't end: for (pfn = start_pfn; pfn < end_pfn; pfn += 1 << order) As suggested by Naoya, below fix checks hugepages_supported() before calling dissolve_free_huge_pages(). [[email protected]: no legitimate reason to call dissolve_free_huge_pages() when !hugepages_supported()] Signed-off-by: Li Zhong <[email protected]> Acked-by: Naoya Horiguchi <[email protected]> Acked-by: David Rientjes <[email protected]> Signed-off-by: David Rientjes <[email protected]> Cc: <[email protected]> [3.12+] Signed-off-by: Andrew Morton <[email protected]> --- mm/hugetlb.c | 3 +++ 1 file changed, 3 insertions(+) diff -puN mm/hugetlb.c~mm-fix-potential-infinite-loop-in-dissolve_free_huge_pages mm/hugetlb.c --- a/mm/hugetlb.c~mm-fix-potential-infinite-loop-in-dissolve_free_huge_pages +++ a/mm/hugetlb.c @@ -1088,6 +1088,9 @@ void dissolve_free_huge_pages(unsigned l unsigned long pfn; struct hstate *h; + if (!hugepages_supported()) + return; + /* Set scan step to minimum hugepage size */ for_each_hstate(h) if (order > huge_page_order(h)) _ -- To unsubscribe from this list: send the line "unsubscribe stable" in the body of a message to [email protected] More majordomo info at http://vger.kernel.org/majordomo-info.html
