mm/memory-failure: reject unsupported non-folio compound page

When !CONFIG_TRANSPARENT_HUGEPAGE, a non-folio compound page can appear in
a userspace mapping via either vm_insert_*() functions or
vm_operatios_struct->fault().  They are not folios, thus should not be
considered for folio operations like split.  To reject these pages, make
sure get_hwpoison_page() is always called as HWPoisonHandlable() will do
the right work.

[Some commit log borrowed from Zi Yan. Thanks.]

Link: https://lkml.kernel.org/r/20260205075328.523211-1-linmiaohe@huawei.com
Fixes: 689b8986776c ("mm/memory-failure: improve large block size folio handling")
Signed-off-by: Miaohe Lin <linmiaohe@huawei.com>
Reported-by: 是参差 <shicenci@gmail.com>
Closes: https://lore.kernel.org/all/PS1PPF7E1D7501F1E4F4441E7ECD056DEADAB98A@PS1PPF7E1D7501F.apcprd02.prod.outlook.com/
Reviewed-by: Zi Yan <ziy@nvidia.com>
Tested-by: Zi Yan <ziy@nvidia.com>
Cc: David Hildenbrand <david@kernel.org>
Cc: Jane Chu <jane.chu@oracle.com>
Cc: Miaohe Lin <linmiaohe@huawei.com>
Cc: Naoya Horiguchi <nao.horiguchi@gmail.com>
Signed-off-by: Andrew Morton <akpm@linux-foundation.org>

diff --git a/mm/memory-failure.c b/mm/memory-failure.c
index cf0d526e6d418e0bc14f19d7b45cfaccbdfeda78..9fd8355176eb9fceb3f4f0b3038babff2331d994 100644 (file)
--- a/mm/memory-failure.c
+++ b/mm/memory-failure.c
@@ -2411,31 +2411,29 @@ try_again:
         * In fact it's dangerous to directly bump up page count from 0,
         * that may make page_ref_freeze()/page_ref_unfreeze() mismatch.
         */
-       if (!(flags & MF_COUNT_INCREASED)) {
-               res = get_hwpoison_page(p, flags);
-               if (!res) {
-                       if (is_free_buddy_page(p)) {
-                               if (take_page_off_buddy(p)) {
-                                       page_ref_inc(p);
-                                       res = MF_RECOVERED;
-                               } else {
-                                       /* We lost the race, try again */
-                                       if (retry) {
-                                               ClearPageHWPoison(p);
-                                               retry = false;
-                                               goto try_again;
-                                       }
-                                       res = MF_FAILED;
-                               }
-                               res = action_result(pfn, MF_MSG_BUDDY, res);
+       res = get_hwpoison_page(p, flags);
+       if (!res) {
+               if (is_free_buddy_page(p)) {
+                       if (take_page_off_buddy(p)) {
+                               page_ref_inc(p);
+                               res = MF_RECOVERED;
                        } else {
-                               res = action_result(pfn, MF_MSG_KERNEL_HIGH_ORDER, MF_IGNORED);
+                               /* We lost the race, try again */
+                               if (retry) {
+                                       ClearPageHWPoison(p);
+                                       retry = false;
+                                       goto try_again;
+                               }
+                               res = MF_FAILED;
                        }
-                       goto unlock_mutex;
-               } else if (res < 0) {
-                       res = action_result(pfn, MF_MSG_GET_HWPOISON, MF_IGNORED);
-                       goto unlock_mutex;
+                       res = action_result(pfn, MF_MSG_BUDDY, res);
+               } else {
+                       res = action_result(pfn, MF_MSG_KERNEL_HIGH_ORDER, MF_IGNORED);
                }
+               goto unlock_mutex;
+       } else if (res < 0) {
+               res = action_result(pfn, MF_MSG_GET_HWPOISON, MF_IGNORED);
+               goto unlock_mutex;
        }
 
        folio = page_folio(p);