[PATCH] test_meminit: use GFP_ATOMIC in RCU critical section

From: Alexander Potapenko
Date: Thu Jul 25 2019 - 14:06:00 EST


kmalloc() shouldn't sleep while in RCU critical section, therefore
use GFP_ATOMIC instead of GFP_KERNEL.

The bug has been spotted by the 0day kernel testing robot.

Fixes: 7e659650cbda ("lib: introduce test_meminit module")
Signed-off-by: Alexander Potapenko <glider@xxxxxxxxxx>
Cc: Kees Cook <keescook@xxxxxxxxxxxx>
Cc: Andrew Morton <akpm@xxxxxxxxxxxxxxxxxxxx>
Cc: linux-kernel@xxxxxxxxxxxxxxx
Cc: linux-mm@xxxxxxxxx
Cc: linux-security-module@xxxxxxxxxxxxxxx
---
lib/test_meminit.c | 2 +-
1 file changed, 1 insertion(+), 1 deletion(-)

diff --git a/lib/test_meminit.c b/lib/test_meminit.c
index 62d19f270cad..9729f271d150 100644
--- a/lib/test_meminit.c
+++ b/lib/test_meminit.c
@@ -222,7 +222,7 @@ static int __init do_kmem_cache_size(size_t size, bool want_ctor,
* Copy the buffer to check that it's not wiped on
* free().
*/
- buf_copy = kmalloc(size, GFP_KERNEL);
+ buf_copy = kmalloc(size, GFP_ATOMIC);
if (buf_copy)
memcpy(buf_copy, buf, size);

--
2.22.0.657.g960e92d24f-goog