[PATCH] mm/mmap: Properly unaccount memory on mas_preallocate() failure

From: Alistair Popple
Date: Thu Dec 01 2022 - 23:54:35 EST


security_vm_enough_memory_mm() accounts memory via a call to
vm_acct_memory(). Therefore any subsequent failures should unaccount
for this memory prior to returning the error.

Signed-off-by: Alistair Popple <apopple@xxxxxxxxxx>
Fixes: 28c5609fb236 ("mm/mmap: preallocate maple nodes for brk vma expansion")

---

Pretty trivial fixup that I noticed was needed while working on the
code.
---
mm/mmap.c | 6 +++---
1 file changed, 3 insertions(+), 3 deletions(-)

diff --git a/mm/mmap.c b/mm/mmap.c
index 74a84eb33b90..3e50a571c3c4 100644
--- a/mm/mmap.c
+++ b/mm/mmap.c
@@ -2954,7 +2954,7 @@ static int do_brk_flags(struct ma_state *mas, struct vm_area_struct *vma,
((vma->vm_flags & ~VM_SOFTDIRTY) == flags)) {
mas_set_range(mas, vma->vm_start, addr + len - 1);
if (mas_preallocate(mas, vma, GFP_KERNEL))
- return -ENOMEM;
+ goto unacct_fail;

vma_adjust_trans_huge(vma, vma->vm_start, addr + len, 0);
if (vma->anon_vma) {
@@ -2976,7 +2976,7 @@ static int do_brk_flags(struct ma_state *mas, struct vm_area_struct *vma,
/* create a vma struct for an anonymous mapping */
vma = vm_area_alloc(mm);
if (!vma)
- goto vma_alloc_fail;
+ goto unacct_fail;

vma_set_anonymous(vma);
vma->vm_start = addr;
@@ -3001,7 +3001,7 @@ static int do_brk_flags(struct ma_state *mas, struct vm_area_struct *vma,

mas_store_fail:
vm_area_free(vma);
-vma_alloc_fail:
+unacct_fail:
vm_unacct_memory(len >> PAGE_SHIFT);
return -ENOMEM;
}
--
2.35.1