diff options
| author | David Hildenbrand <david@redhat.com> | 2019-10-18 20:20:05 -0700 |
|---|---|---|
| committer | Greg Kroah-Hartman <gregkh@linuxfoundation.org> | 2019-10-29 09:17:39 +0100 |
| commit | 5e76d606661c22e1b7f011163800ff4ceb0f398c (patch) | |
| tree | 64e749a25023266191fdf10d2b873fc0dd3dadbd /mm | |
| parent | 13e9cf786d03cbabd24f3e0bffb6151d17c6029b (diff) | |
hugetlbfs: don't access uninitialized memmaps in pfn_range_valid_gigantic()
commit f231fe4235e22e18d847e05cbe705deaca56580a upstream.
Uninitialized memmaps contain garbage and in the worst case trigger
kernel BUGs, especially with CONFIG_PAGE_POISONING. They should not get
touched.
Let's make sure that we only consider online memory (managed by the
buddy) that has initialized memmaps. ZONE_DEVICE is not applicable.
page_zone() will call page_to_nid(), which will trigger
VM_BUG_ON_PGFLAGS(PagePoisoned(page), page) with CONFIG_PAGE_POISONING
and CONFIG_DEBUG_VM_PGFLAGS when called on uninitialized memmaps. This
can be the case when an offline memory block (e.g., never onlined) is
spanned by a zone.
Note: As explained by Michal in [1], alloc_contig_range() will verify
the range. So it boils down to the wrong access in this function.
[1] http://lkml.kernel.org/r/20180423000943.GO17484@dhcp22.suse.cz
Link: http://lkml.kernel.org/r/20191015120717.4858-1-david@redhat.com
Fixes: f1dd2cd13c4b ("mm, memory_hotplug: do not associate hotadded memory to zones until online") [visible after d0dc12e86b319]
Signed-off-by: David Hildenbrand <david@redhat.com>
Reported-by: Michal Hocko <mhocko@kernel.org>
Acked-by: Michal Hocko <mhocko@suse.com>
Reviewed-by: Mike Kravetz <mike.kravetz@oracle.com>
Cc: Anshuman Khandual <anshuman.khandual@arm.com>
Cc: <stable@vger.kernel.org> [4.13+]
Signed-off-by: Andrew Morton <akpm@linux-foundation.org>
Signed-off-by: Linus Torvalds <torvalds@linux-foundation.org>
Signed-off-by: Greg Kroah-Hartman <gregkh@linuxfoundation.org>
Diffstat (limited to 'mm')
| -rw-r--r-- | mm/hugetlb.c | 5 |
1 files changed, 2 insertions, 3 deletions
diff --git a/mm/hugetlb.c b/mm/hugetlb.c index 8ca0075a5464..310656b4ede6 100644 --- a/mm/hugetlb.c +++ b/mm/hugetlb.c @@ -1081,11 +1081,10 @@ static bool pfn_range_valid_gigantic(struct zone *z, struct page *page; for (i = start_pfn; i < end_pfn; i++) { - if (!pfn_valid(i)) + page = pfn_to_online_page(i); + if (!page) return false; - page = pfn_to_page(i); - if (page_zone(page) != z) return false; |