Re: [PATCH 43/46] mm/vma: don't leak the charge for stack growth

[Pedro Falcato]

On Tue, Oct 27, 2026 at 12:18:03AM +0100, David Hildenbrand (Arm) wrote:
> acct_stack_growth() charges stack expansion even without VM_ACCOUNT.
> This can happen for read-only or MAP_NORESERVE mappings created with
> MAP_GROWSDOWN. Unmapping these VMAs does not release the charge, leaking
> Committed_AS.
> 
> Only check and charge growth for VM_ACCOUNT VMAs, matching mremap().
> Unaccounted growth skips the overcommit check while remaining subject
> to the other stack-growth limits.
> 
> Fixes: 1da177e4c3f4 ("Linux-2.6.12-rc2")
> Cc: stable@xxxxxxxxxxxxxxx
> Reported-by: Josef Bacik <josef@xxxxxxxxxxxxxx>
> Reviewed-by: Lorenzo Stoakes (ARM) <ljs@xxxxxxxxxx>
> Signed-off-by: David Hildenbrand (Arm) <david@xxxxxxxxxx>

Reviewed-by: Pedro Falcato <pfalcato@xxxxxxx> 

-- 
Pedro