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From:   Deren Wu <Deren.Wu@mediatek.com>
To:     Felix Fietkau <nbd@nbd.name>,
        Lorenzo Bianconi <lorenzo.bianconi@redhat.com>
CC:     Sean Wang <sean.wang@mediatek.com>,
        Soul Huang <Soul.Huang@mediatek.com>,
        YN Chen <YN.Chen@mediatek.com>,
        Leon Yen <Leon.Yen@mediatek.com>,
        "Eric-SY Chang" <Eric-SY.Chang@mediatek.com>,
        Deren Wu <Deren.Wu@mediatek.com>, KM Lin <km.lin@mediatek.com>,
        Robin Chiu <robin.chiu@mediatek.com>,
        CH Yeh <ch.yeh@mediatek.com>, Posh Sun <posh.sun@mediatek.com>,
        Eric Liang <Eric.Liang@mediatek.com>,
        Stella Chang <Stella.Chang@mediatek.com>,
        "Evelyn Tsai" <evelyn.tsai@mediatek.com>,
        Ryder Lee <ryder.lee@mediatek.com>,
        "Shayne Chen" <shayne.chen@mediatek.com>,
        linux-wireless <linux-wireless@vger.kernel.org>,
        linux-mediatek <linux-mediatek@lists.infradead.org>,
        Deren Wu <deren.wu@mediatek.com>
Subject: [PATCH] mt76: mt7615: fix compiler warning on frame size
Date:   Fri, 11 Feb 2022 10:54:55 +0800
Message-ID: <c7c87a448a159a9836b6ac848eb92f6a367daf1a.1644547407.git.deren.wu@mediatek.com>
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From: Deren Wu <deren.wu@mediatek.com>

The following error is see from the compiler:

  mt7615/debugfs.c: In function ‘mt7615_ext_mac_addr_read’:
  mt7615/debugfs.c:465:1: warning: the frame size of 1072 bytes is
    larger than 1024 bytes [-Wframe-larger-than=]

The issue is due to allocating a buffer as string storage.

Fix by converting to a dynamical allocation of the buffer.

Reviewed-by: Ryder Lee <ryder.lee@mediatek.com>
Signed-off-by: Deren Wu <deren.wu@mediatek.com>
---
 .../net/wireless/mediatek/mt76/mt7615/debugfs.c    | 14 +++++++++++---
 1 file changed, 11 insertions(+), 3 deletions(-)

diff --git a/drivers/net/wireless/mediatek/mt76/mt7615/debugfs.c b/drivers/net/wireless/mediatek/mt76/mt7615/debugfs.c
index ca7efca1543f..250faa870db2 100644
--- a/drivers/net/wireless/mediatek/mt76/mt7615/debugfs.c
+++ b/drivers/net/wireless/mediatek/mt76/mt7615/debugfs.c
@@ -443,11 +443,16 @@ mt7615_ext_mac_addr_read(struct file *file, char __user *userbuf,
 			 size_t count, loff_t *ppos)
 {
 	struct mt7615_dev *dev = file->private_data;
-	char buf[32 * ((ETH_ALEN * 3) + 4) + 1];
+	char *buf;
+	static u32 len = 32 * ((ETH_ALEN * 3) + 4) + 1;
 	u8 addr[ETH_ALEN];
 	int ofs = 0;
 	int i;
 
+	buf = kzalloc(len, GFP_KERNEL);
+	if (!buf)
+		return -ENOMEM;
+
 	for (i = 0; i < 32; i++) {
 		if (!(dev->muar_mask & BIT(i)))
 			continue;
@@ -458,10 +463,13 @@ mt7615_ext_mac_addr_read(struct file *file, char __user *userbuf,
 		put_unaligned_le32(mt76_rr(dev, MT_WF_RMAC_MAR0), addr);
 		put_unaligned_le16((mt76_rr(dev, MT_WF_RMAC_MAR1) &
 				    MT_WF_RMAC_MAR1_ADDR), addr + 4);
-		ofs += snprintf(buf + ofs, sizeof(buf) - ofs, "%d=%pM\n", i, addr);
+		ofs += snprintf(buf + ofs, len - ofs, "%d=%pM\n", i, addr);
 	}
 
-	return simple_read_from_buffer(userbuf, count, ppos, buf, ofs);
+	ofs = simple_read_from_buffer(userbuf, count, ppos, buf, ofs);
+
+	kfree(buf);
+	return ofs;
 }
 
 static ssize_t
-- 
2.18.0