[PATCH 5.18 0806/1095] mm/mmap.c: fix missing call to vm_unacct_memory in mmap_region

Greg Kroah-Hartman
2022-08-15T22:28:17Z

From: Miaohe Lin <linmiaohe@huawei.com>

[ 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>
---
mm/mmap.c | 1 -
1 file changed, 1 deletion(-)

diff --git a/mm/mmap.c b/mm/mmap.c
index 313b57d55a63..6d9bfd9c94ca 100644
--- a/mm/mmap.c
+++ b/mm/mmap.c
@@ -1882,7 +1882,6 @@ unsigned long mmap_region(struct file *file, unsigned long addr,

/* 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);
free_vma:
--
2.35.1