mm/memory-failure: fix hardware poison check in unpoison_memory()

It was pointed out[1] that using folio_test_hwpoison() is wrong as we need
to check the indiviual page that has poison.  folio_test_hwpoison() only
checks the head page so go back to using PageHWPoison().

User-visible effects include existing hwpoison-inject tests possibly
failing as unpoisoning a single subpage could lead to unpoisoning an
entire folio.  Memory unpoisoning could also not work as expected as
the function will break early due to only checking the head page and
not the actually poisoned subpage.

[1]: https://lore.kernel.org/lkml/ZLIbZygG7LqSI9xe@casper.infradead.org/

Link: https://lkml.kernel.org/r/20230717181812.167757-1-sidhartha.kumar@oracle.com
Fixes: a6fddef49eef ("mm/memory-failure: convert unpoison_memory() to folios")
Signed-off-by: Sidhartha Kumar <sidhartha.kumar@oracle.com>
Reported-by: Matthew Wilcox (Oracle) <willy@infradead.org>
Acked-by: Naoya Horiguchi <naoya.horiguchi@nec.com>
Reviewed-by: Miaohe Lin <linmiaohe@huawei.com>
Cc: <stable@vger.kernel.org>
Signed-off-by: Andrew Morton <akpm@linux-foundation.org>

diff --git a/mm/memory-failure.c b/mm/memory-failure.c
index e245191e6b049a61ab38876ab027caa5048b393a..ece5d481b5fff923aba2a710aeae1d8dd2539467 100644 (file)
--- a/mm/memory-failure.c
+++ b/mm/memory-failure.c
@@ -2487,7 +2487,7 @@ int unpoison_memory(unsigned long pfn)
                goto unlock_mutex;
        }
 
-       if (!folio_test_hwpoison(folio)) {
+       if (!PageHWPoison(p)) {
                unpoison_pr_info("Unpoison: Page was already unpoisoned %#lx\n",
                                 pfn, &unpoison_rs);
                goto unlock_mutex;