This is a note to let you know that I've just added the patch titled
nommu: fix split_vma() map_count error
to the 6.1-stable tree which can be found at:
http://www.kernel.org/git/?p=linux/kernel/git/stable/stable-queue.git;a=summary
The filename of the patch is:
nommu-fix-split_vma-map_count-error.patch
and it can be found in the queue-6.1 subdirectory.
If you, or anyone else, feels it should not be added to the stable tree,
please let <stable@xxxxxxxxxxxxxxx> know about it.
>From fd9edbdbdcde6b489ce59f326755ef16a2ffadd7 Mon Sep 17 00:00:00 2001
From: Liam Howlett <liam.howlett@xxxxxxxxxx>
Date: Mon, 9 Jan 2023 20:58:20 +0000
Subject: nommu: fix split_vma() map_count error
From: Liam Howlett <liam.howlett@xxxxxxxxxx>
commit fd9edbdbdcde6b489ce59f326755ef16a2ffadd7 upstream.
During the maple tree conversion of nommu, an error in counting the VMAs
was introduced by counting the existing VMA again. The counting used to
be decremented by one and incremented by two, but now it only increments
by two. Fix the counting error by moving the increment outside the
setup_vma_to_mm() function to the callers.
Link: https://lkml.kernel.org/r/20230109205809.956325-1-Liam.Howlett@xxxxxxxxxx
Fixes: 8220543df148 ("nommu: remove uses of VMA linked list")
Signed-off-by: Liam R. Howlett <Liam.Howlett@xxxxxxxxxx>
Cc: Matthew Wilcox (Oracle) <willy@xxxxxxxxxxxxx>
Cc: Vlastimil Babka <vbabka@xxxxxxx>
Cc: Yu Zhao <yuzhao@xxxxxxxxxx>
Cc: <stable@xxxxxxxxxxxxxxx>
Signed-off-by: Andrew Morton <akpm@xxxxxxxxxxxxxxxxxxxx>
Signed-off-by: Greg Kroah-Hartman <gregkh@xxxxxxxxxxxxxxxxxxx>
---
mm/nommu.c | 4 +++-
1 file changed, 3 insertions(+), 1 deletion(-)
diff --git a/mm/nommu.c b/mm/nommu.c
index 844af5be7640..5b83938ecb67 100644
--- a/mm/nommu.c
+++ b/mm/nommu.c
@@ -559,7 +559,6 @@ void vma_mas_remove(struct vm_area_struct *vma, struct ma_state *mas)
static void setup_vma_to_mm(struct vm_area_struct *vma, struct mm_struct *mm)
{
- mm->map_count++;
vma->vm_mm = mm;
/* add the VMA to the mapping */
@@ -587,6 +586,7 @@ static void mas_add_vma_to_mm(struct ma_state *mas, struct mm_struct *mm,
BUG_ON(!vma->vm_region);
setup_vma_to_mm(vma, mm);
+ mm->map_count++;
/* add the VMA to the tree */
vma_mas_store(vma, mas);
@@ -1347,6 +1347,7 @@ int split_vma(struct mm_struct *mm, struct vm_area_struct *vma,
if (vma->vm_file)
return -ENOMEM;
+ mm = vma->vm_mm;
if (mm->map_count >= sysctl_max_map_count)
return -ENOMEM;
@@ -1398,6 +1399,7 @@ int split_vma(struct mm_struct *mm, struct vm_area_struct *vma,
mas_set_range(&mas, vma->vm_start, vma->vm_end - 1);
mas_store(&mas, vma);
vma_mas_store(new, &mas);
+ mm->map_count++;
return 0;
err_mas_preallocate:
--
2.39.1
Patches currently in stable-queue which might be from liam.howlett@xxxxxxxxxx are
queue-6.1/nommu-fix-do_munmap-error-path.patch
queue-6.1/nommu-fix-memory-leak-in-do_mmap-error-path.patch
queue-6.1/nommu-fix-split_vma-map_count-error.patch
