From 876f273154f0ecd5a6656e78a31b75388b4a8a59 Mon Sep 17 00:00:00 2001
From: Miaohe Lin <linmiaohe@huawei.com>
Date: Wed, 7 Sep 2022 09:24:49 +0000
Subject: [PATCH] mm/mmap.c: fix missing call to vm_unacct_memory in
mmap_region
stable inclusion
from stable-v4.19.256
commit f84c69bbb3ccc544f0023c4dbbdf922c09b5d80b
category: bugfix
bugzilla: https://gitee.com/openeuler/kernel/issues/I5Q0SQ
CVE: NA
--------------------------------
[ Upstream commit 7f82f922319ede486540e8746769865b9508d2c2 ]
Since the beginning, charged is set to 0 to avoid calling vm_unacct_memory
twice because vm_unacct_memory will be called by above unmap_region. But
since commit 4f74d2c8e827 ("vm: remove 'nr_accounted' calculations from
the unmap_vmas() interfaces"), unmap_region doesn't call vm_unacct_memory
anymore. So charged shouldn't be set to 0 now otherwise the calling to
paired vm_unacct_memory will be missed and leads to imbalanced account.
Link: https://lkml.kernel.org/r/20220618082027.43391-1-linmiaohe@huawei.com
Fixes: 4f74d2c8e827 ("vm: remove 'nr_accounted' calculations from the unmap_vmas() interfaces")
Signed-off-by: Miaohe Lin <linmiaohe@huawei.com>
Signed-off-by: Andrew Morton <akpm@linux-foundation.org>
Signed-off-by: Sasha Levin <sashal@kernel.org>
Signed-off-by: Yongqiang Liu <liuyongqiang13@huawei.com>
---
mm/mmap.c | 1 -
1 file changed, 1 deletion(-)
diff --git a/mm/mmap.c b/mm/mmap.c
index ce3fba7c31cb..a2699bc10f7b 100644
--- a/mm/mmap.c
+++ b/mm/mmap.c
@@ -2105,7 +2105,6 @@ static unsigned long __mmap_region(struct mm_struct *mm, struct file *file,
/* Undo any partial mapping done by a device driver. */
unmap_region(mm, vma, prev, vma->vm_start, vma->vm_end);
- charged = 0;
if (vm_flags & VM_SHARED)
mapping_unmap_writable(file->f_mapping);
allow_write_and_free_vma:
--
GitLab