linux-kernel - [PATCH 6/6] platform/chrome: cros_ec_spi: drop BUG

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Message-Id: <20220512083627.885338-7-tzungbi@kernel.org>
Date:   Thu, 12 May 2022 16:36:27 +0800
From:   Tzung-Bi Shih <tzungbi@...nel.org>
To:     bleung@...omium.org, groeck@...omium.org
Cc:     chrome-platform@...ts.linux.dev, tzungbi@...nel.org,
        linux-kernel@...r.kernel.org
Subject: [PATCH 6/6] platform/chrome: cros_ec_spi: drop BUG_ON()

It is overkill to crash the kernel if the `din` buffer is going to full
or overflow.

Drop the BUG_ON() and return -EINVAL instead.

Signed-off-by: Tzung-Bi Shih <tzungbi@...nel.org>
---
 drivers/platform/chrome/cros_ec_spi.c | 15 ++++++++++-----
 1 file changed, 10 insertions(+), 5 deletions(-)

diff --git a/drivers/platform/chrome/cros_ec_spi.c b/drivers/platform/chrome/cros_ec_spi.c
index 589f18e9537d..0a938f317adc 100644
--- a/drivers/platform/chrome/cros_ec_spi.c
+++ b/drivers/platform/chrome/cros_ec_spi.c
@@ -160,7 +160,8 @@ static int receive_n_bytes(struct cros_ec_device *ec_dev, u8 *buf, int n)
 	struct spi_message msg;
 	int ret;
 
-	BUG_ON(buf - ec_dev->din + n > ec_dev->din_size);
+	if (buf - ec_dev->din + n > ec_dev->din_size)
+		return -EINVAL;
 
 	memset(&trans, 0, sizeof(trans));
 	trans.cs_change = 1;
@@ -197,7 +198,8 @@ static int cros_ec_spi_receive_packet(struct cros_ec_device *ec_dev,
 	unsigned long deadline;
 	int todo;
 
-	BUG_ON(ec_dev->din_size < EC_MSG_PREAMBLE_COUNT);
+	if (ec_dev->din_size < EC_MSG_PREAMBLE_COUNT)
+		return -EINVAL;
 
 	/* Receive data until we see the header byte */
 	deadline = jiffies + msecs_to_jiffies(EC_MSG_DEADLINE_MS);
@@ -237,7 +239,8 @@ static int cros_ec_spi_receive_packet(struct cros_ec_device *ec_dev,
 	 * start of our buffer
 	 */
 	todo = end - ++ptr;
-	BUG_ON(todo < 0 || todo > ec_dev->din_size);
+	if (todo < 0 || todo > ec_dev->din_size)
+		return -EINVAL;
 	todo = min(todo, need_len);
 	memmove(ec_dev->din, ptr, todo);
 	ptr = ec_dev->din + todo;
@@ -305,7 +308,8 @@ static int cros_ec_spi_receive_response(struct cros_ec_device *ec_dev,
 	unsigned long deadline;
 	int todo;
 
-	BUG_ON(ec_dev->din_size < EC_MSG_PREAMBLE_COUNT);
+	if (ec_dev->din_size < EC_MSG_PREAMBLE_COUNT)
+		return -EINVAL;
 
 	/* Receive data until we see the header byte */
 	deadline = jiffies + msecs_to_jiffies(EC_MSG_DEADLINE_MS);
@@ -345,7 +349,8 @@ static int cros_ec_spi_receive_response(struct cros_ec_device *ec_dev,
 	 * start of our buffer
 	 */
 	todo = end - ++ptr;
-	BUG_ON(todo < 0 || todo > ec_dev->din_size);
+	if (todo < 0 || todo > ec_dev->din_size)
+		return -EINVAL;
 	todo = min(todo, need_len);
 	memmove(ec_dev->din, ptr, todo);
 	ptr = ec_dev->din + todo;
-- 
2.36.0.512.ge40c2bad7a-goog