nilfs2-prevent-general-protection-fault-in-nilfs_clear_dirty_page.patch removed from -mm tree

The quilt patch titled
Subject: nilfs2: prevent general protection fault in nilfs_clear_dirty_page()
has been removed from the -mm tree. Its filename was
nilfs2-prevent-general-protection-fault-in-nilfs_clear_dirty_page.patch

This patch was dropped because it was merged into the mm-hotfixes-stable branch of git://git.kernel.org/pub/scm/linux/kernel/git/akpm/mm

------------------------------------------------------
From: Ryusuke Konishi <[email protected]>
Subject: nilfs2: prevent general protection fault in nilfs_clear_dirty_page()
Date: Mon, 12 Jun 2023 11:14:56 +0900

In a syzbot stress test that deliberately causes file system errors on nilfs2 with a corrupted disk image, it has been reported that nilfs_clear_dirty_page() called from nilfs_clear_dirty_pages() can cause a

general protection fault.

In nilfs_clear_dirty_pages(), when looking up dirty pages from the page cache and calling nilfs_clear_dirty_page() for each dirty page/folio retrieved, the back reference from the argument page to "mapping" may have been changed to NULL (and possibly others). It is necessary to check this after locking the page/folio.

So, fix this issue by not calling nilfs_clear_dirty_page() on a page/folio after locking it in nilfs_clear_dirty_pages() if the back reference "mapping" from the page/folio is different from the "mapping" that held the page/folio just before.

---

 fs/nilfs2/page.c |   10 +++++++++-
 1 file changed, 9 insertions(+), 1 deletion(-)

@@ -370,7 +370,15 @@ void nilfs_clear_dirty_pages(struct addr
 			struct folio *folio = fbatch.folios[i];
 
 			folio_lock(folio);
-			nilfs_clear_dirty_page(&folio->page, silent);
+
+			/*
+			 * This folio may have been removed from the address
+			 * space by truncation or invalidation when the lock
+			 * was acquired.  Skip processing in that case.
+			 */
+			if (likely(folio->mapping == mapping))
+				nilfs_clear_dirty_page(&folio->page, silent);
+
 			folio_unlock(folio);
 		}
 		folio_batch_release(&fbatch);

_

Patches currently in -mm which might be from [email protected] are