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authorNaoya Horiguchi <naoya.horiguchi@nec.com>2022-09-08 07:11:50 +0300
committerAndrew Morton <akpm@linux-foundation.org>2022-09-26 22:14:33 +0300
commit2b7aa91ba0e86b8643f5d3c83874c80599c731d7 (patch)
tree19349cd5a50e1f060e328646a9d7214c8b9cd906 /mm
parent58d426a7ba92870d489686dfdb9d06b66815a2ab (diff)
downloadlinux-2b7aa91ba0e86b8643f5d3c83874c80599c731d7.tar.xz
mm/huge_memory: use pfn_to_online_page() in split_huge_pages_all()
NULL pointer dereference is triggered when calling thp split via debugfs on the system with offlined memory blocks. With debug option enabled, the following kernel messages are printed out: page:00000000467f4890 refcount:1 mapcount:0 mapping:0000000000000000 index:0x0 pfn:0x121c000 flags: 0x17fffc00000000(node=0|zone=2|lastcpupid=0x1ffff) raw: 0017fffc00000000 0000000000000000 dead000000000122 0000000000000000 raw: 0000000000000000 0000000000000000 00000001ffffffff 0000000000000000 page dumped because: unmovable page page:000000007d7ab72e is uninitialized and poisoned page dumped because: VM_BUG_ON_PAGE(PagePoisoned(p)) ------------[ cut here ]------------ kernel BUG at include/linux/mm.h:1248! invalid opcode: 0000 [#1] PREEMPT SMP PTI CPU: 16 PID: 20964 Comm: bash Tainted: G I 6.0.0-rc3-foll-numa+ #41 ... RIP: 0010:split_huge_pages_write+0xcf4/0xe30 This shows that page_to_nid() in page_zone() is unexpectedly called for an offlined memmap. Use pfn_to_online_page() to get struct page in PFN walker. Link: https://lkml.kernel.org/r/20220908041150.3430269-1-naoya.horiguchi@linux.dev Fixes: f1dd2cd13c4b ("mm, memory_hotplug: do not associate hotadded memory to zones until online") [visible after d0dc12e86b319] Signed-off-by: Naoya Horiguchi <naoya.horiguchi@nec.com> Co-developed-by: David Hildenbrand <david@redhat.com> Signed-off-by: David Hildenbrand <david@redhat.com> Reviewed-by: Yang Shi <shy828301@gmail.com> Acked-by: Michal Hocko <mhocko@suse.com> Reviewed-by: Miaohe Lin <linmiaohe@huawei.com> Reviewed-by: Oscar Salvador <osalvador@suse.de> Acked-by: Kirill A. Shutemov <kirill.shutemov@linux.intel.com> Cc: Matthew Wilcox <willy@infradead.org> Cc: Muchun Song <songmuchun@bytedance.com> Cc: <stable@vger.kernel.org> [5.10+] Signed-off-by: Andrew Morton <akpm@linux-foundation.org>
Diffstat (limited to 'mm')
-rw-r--r--mm/huge_memory.c6
1 files changed, 2 insertions, 4 deletions
diff --git a/mm/huge_memory.c b/mm/huge_memory.c
index e9414ee57c5b..f42bb51e023a 100644
--- a/mm/huge_memory.c
+++ b/mm/huge_memory.c
@@ -2894,11 +2894,9 @@ static void split_huge_pages_all(void)
max_zone_pfn = zone_end_pfn(zone);
for (pfn = zone->zone_start_pfn; pfn < max_zone_pfn; pfn++) {
int nr_pages;
- if (!pfn_valid(pfn))
- continue;
- page = pfn_to_page(pfn);
- if (!get_page_unless_zero(page))
+ page = pfn_to_online_page(pfn);
+ if (!page || !get_page_unless_zero(page))
continue;
if (zone != page_zone(page))