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Date:   Thu, 25 Jul 2019 14:17:03 +0200
Message-Id: <20190725121703.210874-1-glider@google.com>
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Subject: [PATCH] test_meminit: use GFP_ATOMIC in RCU critical section
From:   Alexander Potapenko <glider@google.com>
Cc:     Alexander Potapenko <glider@google.com>,
        Kees Cook <keescook@chromium.org>,
        Andrew Morton <akpm@linux-foundation.org>,
        linux-kernel@vger.kernel.org, linux-mm@kvack.org,
        linux-security-module@vger.kernel.org
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Sender: linux-kernel-owner@vger.kernel.org
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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@google.com>
Cc: Kees Cook <keescook@chromium.org>
Cc: Andrew Morton <akpm@linux-foundation.org>
Cc: linux-kernel@vger.kernel.org
Cc: linux-mm@kvack.org
Cc: linux-security-module@vger.kernel.org
---
 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