[PATCH] mm/percpu: Fix gfp flag in pcpu_balance_populated

From: Wan Jiabing
Date: Fri Jun 18 2021 - 11:15:00 EST


Fix coccicheck warning:

./mm/percpu.c:2045:19-29: ERROR: function pcpu_balance_populated
called on line 2232 inside lock on line 2228 but uses GFP_KERNEL

When pcpu_balance_populated() is called in pcpu_balance_workfn(),
it helds spin_lock but use GFP_KERNEL to alloc mem, which is unsafe.

Signed-off-by: Wan Jiabing <wanjiabing@xxxxxxxx>
---
mm/percpu.c | 2 +-
1 file changed, 1 insertion(+), 1 deletion(-)

diff --git a/mm/percpu.c b/mm/percpu.c
index b4cebeca4c0c..4031f32e6975 100644
--- a/mm/percpu.c
+++ b/mm/percpu.c
@@ -2042,7 +2042,7 @@ static void pcpu_balance_free(bool empty_only)
static void pcpu_balance_populated(void)
{
/* gfp flags passed to underlying allocators */
- const gfp_t gfp = GFP_KERNEL | __GFP_NORETRY | __GFP_NOWARN;
+ const gfp_t gfp = GFP_ATOMIC | __GFP_NORETRY | __GFP_NOWARN;
struct pcpu_chunk *chunk;
int slot, nr_to_pop, ret;

--
2.30.2