The quilt patch titled Subject: mm/memory_hotplug: fix hwpoisoned large folio handling in do_migrate_range has been removed from the -mm tree. Its filename was mm-memory_hotplug-fix-hwpoisoned-large-folio-handling-in-do_migrate_range.patch

This patch was dropped because an alternative patch was or shall be merged

------------------------------------------------------ From: Jinjiang Tu tujinjiang@huawei.com Subject: mm/memory_hotplug: fix hwpoisoned large folio handling in do_migrate_range Date: Fri, 27 Jun 2025 20:57:47 +0800

In do_migrate_range(), the hwpoisoned folio may be large folio, which can't be handled by unmap_poisoned_folio().

I can reproduce this issue in qemu after adding delay in memory_failure()

BUG: kernel NULL pointer dereference, address: 0000000000000000 Workqueue: kacpi_hotplug acpi_hotplug_work_fn RIP: 0010:try_to_unmap_one+0x16a/0xfc0 <TASK> rmap_walk_anon+0xda/0x1f0 try_to_unmap+0x78/0x80 ? __pfx_try_to_unmap_one+0x10/0x10 ? __pfx_folio_not_mapped+0x10/0x10 ? __pfx_folio_lock_anon_vma_read+0x10/0x10 unmap_poisoned_folio+0x60/0x140 do_migrate_range+0x4d1/0x600 ? slab_memory_callback+0x6a/0x190 ? notifier_call_chain+0x56/0xb0 offline_pages+0x3e6/0x460 memory_subsys_offline+0x130/0x1f0 device_offline+0xba/0x110 acpi_bus_offline+0xb7/0x130 acpi_scan_hot_remove+0x77/0x290 acpi_device_hotplug+0x1e0/0x240 acpi_hotplug_work_fn+0x1a/0x30 process_one_work+0x186/0x340

In this case, just make offline_pages() fail.

Also, do_migrate_range() may be called between memory_failure() setting the hwposion flag and isolation of the folio from the lru, so remove WARN_ON().

Also, in other places unmap_poisoned_folio() is called when the folio is isolated, so obey that in do_migrate_range().

Link: https://lkml.kernel.org/r/20250627125747.3094074-3-tujinjiang@huawei.com Fixes: b15c87263a69 ("hwpoison, memory_hotplug: allow hwpoisoned pages to be offlined") Signed-off-by: Jinjiang Tu tujinjiang@huawei.com Cc: David Hildenbrand david@redhat.com Cc: Kefeng Wang wangkefeng.wang@huawei.com Cc: Miaohe Lin linmiaohe@huawei.com Cc: Michal Hocko mhocko@kernel.org Cc: Oscar Salvador osalvador@suse.de Cc: stable@vger.kernel.org Signed-off-by: Andrew Morton akpm@linux-foundation.org ---

mm/memory_hotplug.c | 21 +++++++++++++-------- 1 file changed, 13 insertions(+), 8 deletions(-)

--- a/mm/memory_hotplug.c~mm-memory_hotplug-fix-hwpoisoned-large-folio-handling-in-do_migrate_range +++ a/mm/memory_hotplug.c @@ -1791,7 +1791,7 @@ found: return 0; }

-static void do_migrate_range(unsigned long start_pfn, unsigned long end_pfn) +static int do_migrate_range(unsigned long start_pfn, unsigned long end_pfn) { struct folio *folio; unsigned long pfn; @@ -1815,8 +1815,10 @@ static void do_migrate_range(unsigned lo pfn = folio_pfn(folio) + folio_nr_pages(folio) - 1;

if (folio_contain_hwpoisoned_page(folio)) { - if (WARN_ON(folio_test_lru(folio))) - folio_isolate_lru(folio); + if (folio_test_large(folio) && !folio_test_hugetlb(folio)) + goto err_out; + if (folio_test_lru(folio) && !folio_isolate_lru(folio)) + goto err_out; if (folio_mapped(folio)) { folio_lock(folio); unmap_poisoned_folio(folio, pfn, false); @@ -1873,6 +1875,11 @@ put_folio: putback_movable_pages(&source); } } + return 0; +err_out: + folio_put(folio); + putback_movable_pages(&source); + return -EBUSY; }

static int __init cmdline_parse_movable_node(char *p) @@ -2006,11 +2013,9 @@ int offline_pages(unsigned long start_pf

ret = scan_movable_pages(pfn, end_pfn, &pfn); if (!ret) { - /* - * TODO: fatal migration failures should bail - * out - */ - do_migrate_range(pfn, end_pfn); + ret = do_migrate_range(pfn, end_pfn); + if (ret) + break; } } while (!ret);

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Patches currently in -mm which might be from tujinjiang@huawei.com are