FAILED: patch "[PATCH] mm: fix apply_to_existing_page_range()" failed to apply to 5.15-stable tree

FAILED: patch "[PATCH] mm: fix apply_to_existing_page_range()" failed to apply to 5.15-stable tree

[gregkh]

The patch below does not apply to the 5.15-stable tree.
If someone wants it applied there, or to any other stable or longterm
tree, then please email the backport, including the original git commit
id to <stable@vger.kernel.org>.

To reproduce the conflict and resubmit, you may use the following commands:

git fetch https://git.kernel.org/pub/scm/linux/kernel/git/stable/linux.git/ linux-5.15.y
git checkout FETCH_HEAD
git cherry-pick -x a995199384347261bb3f21b2e171fa7f988bd2f8
# <resolve conflicts, build, test, etc.>
git commit -s
git send-email --to '<stable@vger.kernel.org>' --in-reply-to '2025042115-penholder-famished-11cb@gregkh' --subject-prefix 'PATCH 5.15.y' HEAD^..

Possible dependencies:



thanks,

greg k-h

------------------ original commit in Linus's tree ------------------

From a995199384347261bb3f21b2e171fa7f988bd2f8 Mon Sep 17 00:00:00 2001
From: "Kirill A. Shutemov" <kirill.shutemov@linux.intel.com>
Date: Wed, 9 Apr 2025 12:40:43 +0300
Subject: [PATCH] mm: fix apply_to_existing_page_range()

In the case of apply_to_existing_page_range(), apply_to_pte_range() is
reached with 'create' set to false.  When !create, the loop over the PTE
page table is broken.

apply_to_pte_range() will only move to the next PTE entry if 'create' is
true or if the current entry is not pte_none().

This means that the user of apply_to_existing_page_range() will not have
'fn' called for any entries after the first pte_none() in the PTE page
table.

Fix the loop logic in apply_to_pte_range().

There are no known runtime issues from this, but the fix is trivial enough
for stable@ even without a known buggy user.

Link: https://lkml.kernel.org/r/20250409094043.1629234-1-kirill.shutemov@linux.intel.com
Signed-off-by: Kirill A. Shutemov <kirill.shutemov@linux.intel.com>
Fixes: be1db4753ee6 ("mm/memory.c: add apply_to_existing_page_range() helper")
Cc: Daniel Axtens <dja@axtens.net>
Cc: David Hildenbrand <david@redhat.com>
Cc: Vlastimil Babka <vbabka@suse.cz>
Cc: <stable@vger.kernel.org>
Signed-off-by: Andrew Morton <akpm@linux-foundation.org>

diff --git a/mm/memory.c b/mm/memory.c
index 1a35165622e1..44481fe7c629 100644
--- a/mm/memory.c
+++ b/mm/memory.c
@@ -2938,11 +2938,11 @@ static int apply_to_pte_range(struct mm_struct *mm, pmd_t *pmd,
 	if (fn) {
 		do {
 			if (create || !pte_none(ptep_get(pte))) {
-				err = fn(pte++, addr, data);
+				err = fn(pte, addr, data);
 				if (err)
 					break;
 			}
-		} while (addr += PAGE_SIZE, addr != end);
+		} while (pte++, addr += PAGE_SIZE, addr != end);
 	}
 	*mask |= PGTBL_PTE_MODIFIED;
 

[PATCH 5.15.y] mm: fix apply_to_existing_page_range()

[Kirill A. Shutemov]

In the case of apply_to_existing_page_range(), apply_to_pte_range() is
reached with 'create' set to false.  When !create, the loop over the PTE
page table is broken.

apply_to_pte_range() will only move to the next PTE entry if 'create' is
true or if the current entry is not pte_none().

This means that the user of apply_to_existing_page_range() will not have
'fn' called for any entries after the first pte_none() in the PTE page
table.

Fix the loop logic in apply_to_pte_range().

There are no known runtime issues from this, but the fix is trivial enough
for stable@ even without a known buggy user.

Link: https://lkml.kernel.org/r/20250409094043.1629234-1-kirill.shutemov@linux.intel.com
Signed-off-by: Kirill A. Shutemov <kirill.shutemov@linux.intel.com>
Fixes: be1db4753ee6 ("mm/memory.c: add apply_to_existing_page_range() helper")
Cc: Daniel Axtens <dja@axtens.net>
Cc: David Hildenbrand <david@redhat.com>
Cc: Vlastimil Babka <vbabka@suse.cz>
Cc: <stable@vger.kernel.org>
Signed-off-by: Andrew Morton <akpm@linux-foundation.org>
(cherry picked from commit a995199384347261bb3f21b2e171fa7f988bd2f8)
Signed-off-by: Kirill A. Shutemov <kirill.shutemov@linux.intel.com>
---
 mm/memory.c | 4 ++--
 1 file changed, 2 insertions(+), 2 deletions(-)

diff --git a/mm/memory.c b/mm/memory.c
index 62fe3707ff92..4998b4c49052 100644
--- a/mm/memory.c
+++ b/mm/memory.c
@@ -2570,11 +2570,11 @@ static int apply_to_pte_range(struct mm_struct *mm, pmd_t *pmd,
 	if (fn) {
 		do {
 			if (create || !pte_none(*pte)) {
-				err = fn(pte++, addr, data);
+				err = fn(pte, addr, data);
 				if (err)
 					break;
 			}
-		} while (addr += PAGE_SIZE, addr != end);
+		} while (pte++, addr += PAGE_SIZE, addr != end);
 	}
 	*mask |= PGTBL_PTE_MODIFIED;
 
-- 
2.47.2

Re: [PATCH 5.15.y] mm: fix apply_to_existing_page_range()

[Sasha Levin]

[ Sasha's backport helper bot ]

Hi,

Summary of potential issues:
⚠️ Found matching upstream commit but patch is missing proper reference to it

Found matching upstream commit: a995199384347261bb3f21b2e171fa7f988bd2f8

Status in newer kernel trees:
6.14.y | Not found
6.12.y | Not found
6.6.y | Not found
6.1.y | Not found

Note: The patch differs from the upstream commit:
---
1:  a995199384347 ! 1:  35ec614cdbbfe mm: fix apply_to_existing_page_range()
    @@ Commit message
         Cc: Vlastimil Babka <vbabka@suse.cz>
         Cc: <stable@vger.kernel.org>
         Signed-off-by: Andrew Morton <akpm@linux-foundation.org>
    +    (cherry picked from commit a995199384347261bb3f21b2e171fa7f988bd2f8)
    +    Signed-off-by: Kirill A. Shutemov <kirill.shutemov@linux.intel.com>
     
      ## mm/memory.c ##
     @@ mm/memory.c: static int apply_to_pte_range(struct mm_struct *mm, pmd_t *pmd,
      	if (fn) {
      		do {
    - 			if (create || !pte_none(ptep_get(pte))) {
    + 			if (create || !pte_none(*pte)) {
     -				err = fn(pte++, addr, data);
     +				err = fn(pte, addr, data);
      				if (err)
---

Results of testing on various branches:

| Branch                    | Patch Apply | Build Test |
|---------------------------|-------------|------------|
| stable/linux-5.15.y       |  Success    |  Success   |