linux-kernel - [PATCH v2 7/7] platform/chrome: cros_ec_spi: drop BUG

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Date:   Fri, 13 May 2022 12:41:43 +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 v2 7/7] platform/chrome: cros_ec_spi: drop BUG_ON() if `din` isn't large enough

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>
---
Changes from v1:
- Separate from the original 6th patch.

 drivers/platform/chrome/cros_ec_spi.c | 9 ++++++---
 1 file changed, 6 insertions(+), 3 deletions(-)

diff --git a/drivers/platform/chrome/cros_ec_spi.c b/drivers/platform/chrome/cros_ec_spi.c
index 5264615f46af..7360b3ff6e4f 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);
@@ -304,7 +306,8 @@ 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);
-- 
2.36.0.550.gb090851708-goog