FAILED: patch "[PATCH] mm/vma: don't leak the charge for stack growth" failed to apply to 6.6-stable tree

[Sasha Levin <sashal@kernel.org>]

The patch below does not apply to the 6.6-stable tree.
If someone wants it applied there, or to any other stable or longterm
tree, then please email the backport, including the original git commit
id to <stable@vger.kernel.org>.

To reproduce the conflict and resubmit, you may use the following commands:

git fetch https://git.kernel.org/pub/scm/linux/kernel/git/stable/linux.git/ linux-6.6.y
git checkout FETCH_HEAD
git cherry-pick -x b1ee87802111156e27557e82acc31fa7dfc76e2a
# <resolve conflicts, build, test, etc.>
git commit -s
git send-email --to '<stable@vger.kernel.org>' --in-reply-to '20261109201404-failed-6.6-b1ee87802111@kernel.org' --subject-prefix 'PATCH 6.6.y' 'HEAD^..'

Thanks,
Sasha

------------------ original commit in Linus's tree ------------------

From b1ee87802111156e27557e82acc31fa7dfc76e2a Mon Sep 17 00:00:00 2001
From: "David Hildenbrand (Arm)" <david@kernel.org>
Date: Sat, 31 Oct 2026 10:40:13 +0100
Subject: [PATCH] mm/vma: don't leak the charge for stack growth

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@vger.kernel.org
Reported-by: Josef Bacik <josef@toxicpanda.com>
Reviewed-by: Lorenzo Stoakes (ARM) <ljs@kernel.org>
Reviewed-by: Pedro Falcato <pfalcato@suse.de>
Reviewed-by: Harry Yoo (Meta) <harry@kernel.org>
Tested-by: Muhammad Usama Anjum <usama.anjum@arm.com>
Link: https://patch.msgid.link/20261031-fixes_core-v3-44-d6437171ecc3@kernel.org
Signed-off-by: David Hildenbrand (Arm) <david@kernel.org>
---
 mm/vma.c | 3 ++-
 1 file changed, 2 insertions(+), 1 deletion(-)

diff --git a/mm/vma.c b/mm/vma.c
index acdf00346cda5..695d0be85ac86 100644
--- a/mm/vma.c
+++ b/mm/vma.c
@@ -3391,7 +3391,8 @@ static int acct_stack_growth(struct vm_area_struct *vma,
 	 * Overcommit..  This must be the final test, as it will
 	 * update security statistics.
 	 */
-	if (security_vm_enough_memory_mm(mm, grow))
+	if (vma_test(vma, VMA_ACCOUNT_BIT) &&
+	    security_vm_enough_memory_mm(mm, grow))
 		return -ENOMEM;
 
 	return 0;
-- 
2.53.0