The patch below does not apply to the 5.15-stable tree.
If someone wants it applied there, or to any other stable or longterm
tree, then please email the backport, including the original git commit
id to <stable@xxxxxxxxxxxxxxx>.
Possible dependencies:
2b7aa91ba0e8 ("mm/huge_memory: use pfn_to_online_page() in split_huge_pages_all()")
a17206dac7b2 ("mm/huge_memory: minor cleanup for split_huge_pages_all")
thanks,
greg k-h
------------------ original commit in Linus's tree ------------------
>From 2b7aa91ba0e86b8643f5d3c83874c80599c731d7 Mon Sep 17 00:00:00 2001
From: Naoya Horiguchi <naoya.horiguchi@xxxxxxx>
Date: Thu, 8 Sep 2022 13:11:50 +0900
Subject: [PATCH] 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@xxxxxxxxx
Fixes: f1dd2cd13c4b ("mm, memory_hotplug: do not associate hotadded memory to zones until online") [visible after d0dc12e86b319]
Signed-off-by: Naoya Horiguchi <naoya.horiguchi@xxxxxxx>
Co-developed-by: David Hildenbrand <david@xxxxxxxxxx>
Signed-off-by: David Hildenbrand <david@xxxxxxxxxx>
Reviewed-by: Yang Shi <shy828301@xxxxxxxxx>
Acked-by: Michal Hocko <mhocko@xxxxxxxx>
Reviewed-by: Miaohe Lin <linmiaohe@xxxxxxxxxx>
Reviewed-by: Oscar Salvador <osalvador@xxxxxxx>
Acked-by: Kirill A. Shutemov <kirill.shutemov@xxxxxxxxxxxxxxx>
Cc: Matthew Wilcox <willy@xxxxxxxxxxxxx>
Cc: Muchun Song <songmuchun@xxxxxxxxxxxxx>
Cc: <stable@xxxxxxxxxxxxxxx> [5.10+]
Signed-off-by: Andrew Morton <akpm@xxxxxxxxxxxxxxxxxxxx>
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))
