@@ -1321,14 +1321,16 @@ static inline void destroy_compound_giga
static void update_and_free_page(struct hstate *h, struct page *page)
{
int i;
+ struct page *subpage = page;
if (hstate_is_gigantic(h) && !gigantic_page_runtime_supported())
return;
h->nr_huge_pages--;
h->nr_huge_pages_node[page_to_nid(page)]--;
- for (i = 0; i < pages_per_huge_page(h); i++) {
- page[i].flags &= ~(1 << PG_locked | 1 << PG_error |
+ for (i = 0; i < pages_per_huge_page(h);
+ i++, subpage = mem_map_next(subpage, page, i)) {
+ subpage->flags &= ~(1 << PG_locked | 1 << PG_error |
1 << PG_referenced | 1 << PG_dirty |
1 << PG_active | 1 << PG_private |
1 << PG_writeback);
The patch titled Subject: hugetlb: fix update_and_free_page contig page struct assumption has been added to the -mm tree. Its filename is hugetlb-fix-update_and_free_page-contig-page-struct-assumption.patch This patch should soon appear at https://ozlabs.org/~akpm/mmots/broken-out/hugetlb-fix-update_and_free_page-contig-page-struct-assumption.patch and later at https://ozlabs.org/~akpm/mmotm/broken-out/hugetlb-fix-update_and_free_page-contig-page-struct-assumption.patch Before you just go and hit "reply", please: a) Consider who else should be cc'ed b) Prefer to cc a suitable mailing list as well c) Ideally: find the original patch on the mailing list and do a reply-to-all to that, adding suitable additional cc's *** Remember to use Documentation/process/submit-checklist.rst when testing your code *** The -mm tree is included into linux-next and is updated there every 3-4 working days ------------------------------------------------------ From: Mike Kravetz <mike.kravetz@oracle.com> Subject: hugetlb: fix update_and_free_page contig page struct assumption page structs are not guaranteed to be contiguous for gigantic pages. The routine update_and_free_page can encounter a gigantic page, yet it assumes page structs are contiguous when setting page flags in subpages. If update_and_free_page encounters non-contiguous page structs, we can see “BUG: Bad page state in process …” errors. Non-contiguous page structs are generally not an issue. However, they can exist with a specific kernel configuration and hotplug operations. For example: Configure the kernel with CONFIG_SPARSEMEM and !CONFIG_SPARSEMEM_VMEMMAP. Then, hotplug add memory for the area where the gigantic page will be allocated. Zi Yan outlined steps to reproduce here [1]. [1] https://lore.kernel.org/linux-mm/16F7C58B-4D79-41C5-9B64-A1A1628F4AF2@nvidia.com/ Link: https://lkml.kernel.org/r/20210217184926.33567-1-mike.kravetz@oracle.com Fixes: 944d9fec8d7a ("hugetlb: add support for gigantic page allocation at runtime") Signed-off-by: Zi Yan <ziy@nvidia.com> Signed-off-by: Mike Kravetz <mike.kravetz@oracle.com> Cc: Zi Yan <ziy@nvidia.com> Cc: Davidlohr Bueso <dbueso@suse.de> Cc: "Kirill A . Shutemov" <kirill.shutemov@linux.intel.com> Cc: Andrea Arcangeli <aarcange@redhat.com> Cc: Matthew Wilcox <willy@infradead.org> Cc: Oscar Salvador <osalvador@suse.de> Cc: Joao Martins <joao.m.martins@oracle.com> Cc: <stable@vger.kernel.org> Signed-off-by: Andrew Morton <akpm@linux-foundation.org> --- mm/hugetlb.c | 6 ++++-- 1 file changed, 4 insertions(+), 2 deletions(-)