From: Jinjiang Tu Date: Fri, 27 Jun 2025 12:57:47 +0000 (+0800) Subject: mm/memory_hotplug: fix hwpoisoned large folio handling in do_migrate_range() X-Git-Url: https://www.infradead.org/git/?a=commitdiff_plain;h=397f6d14f9c370e4910e6885294c340f39dedbf5;p=users%2Fjedix%2Flinux-maple.git mm/memory_hotplug: fix hwpoisoned large folio handling in do_migrate_range() 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 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 Besides, do_migrate_range() may be called between memory_failure set hwpoison flag and isolate the folio from lru, so remove WARN_ON(). In other places, unmap_poisoned_folio() is called when the folio is isolated, obey it in do_migrate_range() too. [david@redhat.com: don't abort offlining, fixed typo, add comment] Link: https://lkml.kernel.org/r/3c214dff-9649-4015-840f-10de0e03ebe4@redhat.com Fixes: b15c87263a69 ("hwpoison, memory_hotplug: allow hwpoisoned pages to be offlined") Signed-off-by: Jinjiang Tu Signed-off-by: David Hildenbrand Acked-by: Zi Yan Reviewed-by: Miaohe Lin Cc: Kefeng Wang Cc: Luis Chamberalin Cc: Matthew Wilcox (Oracle) Cc: Michal Hocko Cc: Oscar Salvador Cc: Pankaj Raghav Signed-off-by: Andrew Morton --- diff --git a/mm/memory_hotplug.c b/mm/memory_hotplug.c index 1f15af712bc34..74318c7877156 100644 --- a/mm/memory_hotplug.c +++ b/mm/memory_hotplug.c @@ -1815,8 +1815,14 @@ static void do_migrate_range(unsigned long start_pfn, unsigned long end_pfn) 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); + /* + * unmap_poisoned_folio() cannot handle large folios + * in all cases yet. + */ + if (folio_test_large(folio) && !folio_test_hugetlb(folio)) + goto put_folio; + if (folio_test_lru(folio) && !folio_isolate_lru(folio)) + goto put_folio; if (folio_mapped(folio)) { folio_lock(folio); unmap_poisoned_folio(folio, pfn, false);