linux-kernel - [PATCH 1/2] myri10ge: avoid passing uninitialized data to inline asm

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Message-Id: <20260203230501.832872-1-arnd@kernel.org>
Date: Wed,  4 Feb 2026 00:04:51 +0100
From: Arnd Bergmann <arnd@...nel.org>
To: Andrew Lunn <andrew+netdev@...n.ch>,
	"David S. Miller" <davem@...emloft.net>,
	Eric Dumazet <edumazet@...gle.com>,
	Jakub Kicinski <kuba@...nel.org>,
	Paolo Abeni <pabeni@...hat.com>,
	"Andrew J. Gallatin" <gallatin@...i.com>,
	Brice Goglin <brice@...i.com>,
	Jeff Garzik <jeff@...zik.org>
Cc: Arnd Bergmann <arnd@...db.de>,
	Ingo Molnar <mingo@...nel.org>,
	Thomas Gleixner <tglx@...nel.org>,
	Bjorn Helgaas <bhelgaas@...gle.com>,
	Lukas Wunner <lukas@...ner.de>,
	netdev@...r.kernel.org,
	linux-kernel@...r.kernel.org
Subject: [PATCH 1/2] myri10ge: avoid passing uninitialized data to inline asm

From: Arnd Bergmann <arnd@...db.de>

Building with gcc-16.0.1 find a bug with the inline asm:

In file included from include/linux/io.h:12,
                 from drivers/net/ethernet/myricom/myri10ge/myri10ge.c:43:
In function '__const_memcpy_toio_aligned64',
    inlined from '__iowrite64_copy' at arch/arm64/include/asm/io.h:249:3,
    inlined from 'myri10ge_dummy_rdma' at drivers/net/ethernet/myricom/myri10ge/myri10ge.c:535:2:
arch/arm64/include/asm/io.h:206:17: error: '*(const u64 *)(&buf[6])' is used uninitialized [-Werror=uninitialized]
  206 |                 asm volatile("str %x0, [%8, #8 * 0]\n"
      |                 ^~~

Set the extra fields to zero before writing them to hardware.

Fixes: 0da34b6dfe55 ("[PATCH] Add Myri-10G Ethernet driver")
Signed-off-by: Arnd Bergmann <arnd@...db.de>
---
 drivers/net/ethernet/myricom/myri10ge/myri10ge.c | 2 +-
 1 file changed, 1 insertion(+), 1 deletion(-)

diff --git a/drivers/net/ethernet/myricom/myri10ge/myri10ge.c b/drivers/net/ethernet/myricom/myri10ge/myri10ge.c
index 7be30a8df268..cea28aa971cc 100644
--- a/drivers/net/ethernet/myricom/myri10ge/myri10ge.c
+++ b/drivers/net/ethernet/myricom/myri10ge/myri10ge.c
@@ -508,7 +508,7 @@ static int myri10ge_read_mac_addr(struct myri10ge_priv *mgp)
 static void myri10ge_dummy_rdma(struct myri10ge_priv *mgp, int enable)
 {
 	char __iomem *submit;
-	__be32 buf[16] __attribute__ ((__aligned__(8)));
+	__be32 buf[16] __attribute__ ((__aligned__(8))) = {};
 	u32 dma_low, dma_high;
 	int i;
 
-- 
2.39.5