[RFC 05/14] fork: check charging success before zeroing stack

[Pasha Tatashin]

No need to do zero cahced stack if memcg charge fails, so move the
charging attempt before the memset operation.

Signed-off-by: Pasha Tatashin <pasha.tatashin@xxxxxxxxxx>
---
 kernel/fork.c | 10 +++++-----
 1 file changed, 5 insertions(+), 5 deletions(-)

diff --git a/kernel/fork.c b/kernel/fork.c
index a35f4008afa0..6a2f2c85e09f 100644
--- a/kernel/fork.c
+++ b/kernel/fork.c
@@ -271,6 +271,11 @@ static int alloc_thread_stack_node(struct task_struct *tsk, int node)
 		if (!vm_area)
 			continue;
 
+		if (memcg_charge_kernel_stack(vm_area)) {
+			vfree(vm_area->addr);
+			return -ENOMEM;
+		}
+
 		/* Reset stack metadata. */
 		kasan_unpoison_range(vm_area->addr, THREAD_SIZE);
 
@@ -279,11 +284,6 @@ static int alloc_thread_stack_node(struct task_struct *tsk, int node)
 		/* Clear stale pointers from reused stack. */
 		memset(stack, 0, THREAD_SIZE);
 
-		if (memcg_charge_kernel_stack(vm_area)) {
-			vfree(vm_area->addr);
-			return -ENOMEM;
-		}
-
 		tsk->stack_vm_area = vm_area;
 		tsk->stack = stack;
 		return 0;
-- 
2.44.0.278.ge034bb2e1d-goog