linux-kernel - [PATCH 06/12] x86: efi: Replace GFP_ATOMIC with GFP_KERNEL in efi_query_variable

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Date:   Thu,  8 Mar 2018 08:00:14 +0000
From:   Ard Biesheuvel <ard.biesheuvel@...aro.org>
To:     linux-efi@...r.kernel.org, Ingo Molnar <mingo@...nel.org>,
        Thomas Gleixner <tglx@...utronix.de>
Cc:     Jia-Ju Bai <baijiaju1990@...il.com>,
        Ard Biesheuvel <ard.biesheuvel@...aro.org>,
        linux-kernel@...r.kernel.org
Subject: [PATCH 06/12] x86: efi: Replace GFP_ATOMIC with GFP_KERNEL in efi_query_variable_store

From: Jia-Ju Bai <baijiaju1990@...il.com>

The function kzalloc here is not called in atomic context.
If nonblocking in efi_query_variable_store is true,
namely it is in atomic context, efi_query_variable_store will return before
this kzalloc is called.
Thus GFP_ATOMIC is not necessary, and it can be replaced with GFP_KERNEL.

This is found by a static analysis tool named DCNS written by myself.

Signed-off-by: Jia-Ju Bai <baijiaju1990@...il.com>
Reviewed-by: Ingo Molnar <mingo@...nel.org>
Signed-off-by: Ard Biesheuvel <ard.biesheuvel@...aro.org>
---
 arch/x86/platform/efi/quirks.c | 2 +-
 1 file changed, 1 insertion(+), 1 deletion(-)

diff --git a/arch/x86/platform/efi/quirks.c b/arch/x86/platform/efi/quirks.c
index 5b513ccffde4..1ef11c26f79b 100644
--- a/arch/x86/platform/efi/quirks.c
+++ b/arch/x86/platform/efi/quirks.c
@@ -177,7 +177,7 @@ efi_status_t efi_query_variable_store(u32 attributes, unsigned long size,
 		 * that by attempting to use more space than is available.
 		 */
 		unsigned long dummy_size = remaining_size + 1024;
-		void *dummy = kzalloc(dummy_size, GFP_ATOMIC);
+		void *dummy = kzalloc(dummy_size, GFP_KERNEL);
 
 		if (!dummy)
 			return EFI_OUT_OF_RESOURCES;
-- 
2.15.1