hugetlb: check for hugetlb folio before vmemmap_restore

In commit d8f5f7e445f0 ("hugetlb: set hugetlb page flag before
optimizing vmemmap") checks were added to print a warning if
hugetlb_vmemmap_restore was called on a non-hugetlb page.

This was mostly due to ordering issues in the hugetlb page set up and tear
down sequencees.  One place missed was the routine
dissolve_free_huge_page.

Naoya Horiguchi noted: "I saw that VM_WARN_ON_ONCE() in
hugetlb_vmemmap_restore is triggered when memory_failure() is called on a
free hugetlb page with vmemmap optimization disabled (the warning is not
triggered if vmemmap optimization is enabled).  I think that we need check
folio_test_hugetlb() before dissolve_free_huge_page() calls
hugetlb_vmemmap_restore_folio()."

Perform the check as suggested by Naoya.

Link: https://lkml.kernel.org/r/20231017032140.GA3680@monkey
Fixes: d8f5f7e445f0 ("hugetlb: set hugetlb page flag before optimizing vmemmap")
Signed-off-by: Mike Kravetz <mike.kravetz@oracle.com>
Suggested-by: Naoya Horiguchi <naoya.horiguchi@linux.dev>
Tested-by: Naoya Horiguchi <naoya.horiguchi@linux.dev>
Cc: Anshuman Khandual <anshuman.khandual@arm.com>
Cc: Barry Song <song.bao.hua@hisilicon.com>
Cc: David Hildenbrand <david@redhat.com>
Cc: David Rientjes <rientjes@google.com>
Cc: Joao Martins <joao.m.martins@oracle.com>
Cc: Matthew Wilcox (Oracle) <willy@infradead.org>
Cc: Miaohe Lin <linmiaohe@huawei.com>
Cc: Michal Hocko <mhocko@suse.com>
Cc: Muchun Song <songmuchun@bytedance.com>
Cc: Oscar Salvador <osalvador@suse.de>
Cc: Xiongchun Duan <duanxiongchun@bytedance.com>
Signed-off-by: Andrew Morton <akpm@linux-foundation.org>

diff --git a/mm/hugetlb.c b/mm/hugetlb.c
index 3fb3a5232173b6af38568c54705d877e8f51a979..dfb4534834f5a0a953089530dfa81ada56805919 100644 (file)
--- a/mm/hugetlb.c
+++ b/mm/hugetlb.c
@@ -2322,17 +2322,23 @@ retry:
                 * need to adjust max_huge_pages if the page is not freed.
                 * Attempt to allocate vmemmmap here so that we can take
                 * appropriate action on failure.
+                *
+                * The folio_test_hugetlb check here is because
+                * remove_hugetlb_folio will clear hugetlb folio flag for
+                * non-vmemmap optimized hugetlb folios.
                 */
-               rc = hugetlb_vmemmap_restore(h, &folio->page);
-               if (!rc) {
-                       update_and_free_hugetlb_folio(h, folio, false);
-               } else {
-                       spin_lock_irq(&hugetlb_lock);
-                       add_hugetlb_folio(h, folio, false);
-                       h->max_huge_pages++;
-                       spin_unlock_irq(&hugetlb_lock);
-               }
+               if (folio_test_hugetlb(folio)) {
+                       rc = hugetlb_vmemmap_restore(h, &folio->page);
+                       if (rc) {
+                               spin_lock_irq(&hugetlb_lock);
+                               add_hugetlb_folio(h, folio, false);
+                               h->max_huge_pages++;
+                               goto out;
+                       }
+               } else
+                       rc = 0;
 
+               update_and_free_hugetlb_folio(h, folio, false);
                return rc;
        }
 out: