+ mm-fix-page-leak-with-multiple-threads-mapping-the-same-page-v2.patch added to mm-hotfixes-unstable branch

[Andrew Morton <akpm@linux-foundation.org>]

The patch titled
     Subject: mm-fix-page-leak-with-multiple-threads-mapping-the-same-page-v2
has been added to the -mm mm-hotfixes-unstable branch.  Its filename is
     mm-fix-page-leak-with-multiple-threads-mapping-the-same-page-v2.patch

This patch will shortly appear at
     https://git.kernel.org/pub/scm/linux/kernel/git/akpm/25-new.git/tree/patches/mm-fix-page-leak-with-multiple-threads-mapping-the-same-page-v2.patch

This patch will later appear in the mm-hotfixes-unstable branch at
    git://git.kernel.org/pub/scm/linux/kernel/git/akpm/mm

Before you just go and hit "reply", please:
   a) Consider who else should be cc'ed
   b) Prefer to cc a suitable mailing list as well
   c) Ideally: find the original patch on the mailing list and do a
      reply-to-all to that, adding suitable additional cc's

*** Remember to use Documentation/process/submit-checklist.rst when testing your code ***

The -mm tree is included into linux-next via the mm-everything
branch at git://git.kernel.org/pub/scm/linux/kernel/git/akpm/mm
and is updated there every 2-3 working days

------------------------------------------------------
From: Josef Bacik <josef@toxicpanda.com>
Subject: mm-fix-page-leak-with-multiple-threads-mapping-the-same-page-v2
Date: Wed, 13 Jul 2022 10:13:37 -0400

Link: https://lkml.kernel.org/r/e90c8f0dbae836632b669c2afc434006a00d4a67.1657721478.git.josef@toxicpanda.com
Fixes: f9ce0be71d1f ("mm: Cleanup faultaround and finish_fault() codepaths")
Signed-off-by: Josef Bacik <josef@toxicpanda.com>
Signed-off-by: Rik van Riel <riel@surriel.com>
Signed-off-by: Chris Mason <clm@fb.com>
Acked-by: Kirill A. Shutemov <kirill.shutemov@linux.intel.com>
Cc: Kirill A. Shutemov <kirill.shutemov@linux.intel.com>
Cc: Matthew Wilcox (Oracle) <willy@infradead.org>
Signed-off-by: Andrew Morton <akpm@linux-foundation.org>
---

 mm/memory.c |    5 ++++-
 1 file changed, 4 insertions(+), 1 deletion(-)

--- a/mm/memory.c~mm-fix-page-leak-with-multiple-threads-mapping-the-same-page-v2
+++ a/mm/memory.c
@@ -4369,7 +4369,10 @@ vm_fault_t finish_fault(struct vm_fault
 			return VM_FAULT_OOM;
 	}
 
-	/* See comment in handle_pte_fault() */
+	/*
+	 * See comment in handle_pte_fault() for how this scenario happens, we
+	 * need to return NOPAGE so that we drop this page.
+	 */
 	if (pmd_devmap_trans_unstable(vmf->pmd))
 		return VM_FAULT_NOPAGE;
 
_

Patches currently in -mm which might be from josef@toxicpanda.com are

mm-fix-page-leak-with-multiple-threads-mapping-the-same-page.patch
mm-fix-page-leak-with-multiple-threads-mapping-the-same-page-v2.patch