Re: FAILED: patch "[PATCH] leds: lm3697: Fix out-of-bound access" failed to apply to 5.9-stable tree

[Sudip Mukherjee <sudipm.mukherjee@xxxxxxxxx>]

Hi Greg,

On Tue, Nov 03, 2020 at 12:58:26PM +0100, gregkh@xxxxxxxxxxxxxxxxxxx wrote:
> 
> The patch below does not apply to the 5.9-stable tree.
> If someone wants it applied there, or to any other stable or longterm
> tree, then please email the backport, including the original git commit
> id to <stable@xxxxxxxxxxxxxxx>.

Here is the backport. Please consider for 5.9-stable.

--
Regards
Sudip

>From cbaecee1e0a2aee549ecbe7f2f66a767794faef8 Mon Sep 17 00:00:00 2001
From: Gabriel David <ultracoolguy@xxxxxxxxxxxx>
Date: Fri, 2 Oct 2020 18:27:00 -0400
Subject: [PATCH] leds: lm3697: Fix out-of-bound access

commit 98d278ca00bd8f62c8bc98bd9e65372d16eb6956 upstream

If both LED banks aren't used in device tree, an out-of-bounds
condition in lm3697_init occurs because of the for loop assuming that
all the banks are used.  Fix it by adding a variable that contains the
number of used banks.

Signed-off-by: Gabriel David <ultracoolguy@xxxxxxxxxxxx>
[removed extra rename, minor tweaks]
Signed-off-by: Pavel Machek <pavel@xxxxxx>
Cc: stable@xxxxxxxxxx
[sudip: use client->dev]
Signed-off-by: Sudip Mukherjee <sudipm.mukherjee@xxxxxxxxx>
---
 drivers/leds/leds-lm3697.c | 8 +++++---
 1 file changed, 5 insertions(+), 3 deletions(-)

diff --git a/drivers/leds/leds-lm3697.c b/drivers/leds/leds-lm3697.c
index 024983088d59..31f5ed486839 100644
--- a/drivers/leds/leds-lm3697.c
+++ b/drivers/leds/leds-lm3697.c
@@ -78,6 +78,7 @@ struct lm3697 {
 	struct mutex lock;
 
 	int bank_cfg;
+	int num_banks;
 
 	struct lm3697_led leds[];
 };
@@ -180,7 +181,7 @@ static int lm3697_init(struct lm3697 *priv)
 	if (ret)
 		dev_err(&priv->client->dev, "Cannot write OUTPUT config\n");
 
-	for (i = 0; i < LM3697_MAX_CONTROL_BANKS; i++) {
+	for (i = 0; i < priv->num_banks; i++) {
 		led = &priv->leds[i];
 		ret = ti_lmu_common_set_ramp(&led->lmu_data);
 		if (ret)
@@ -307,8 +308,8 @@ static int lm3697_probe(struct i2c_client *client,
 	int ret;
 
 	count = device_get_child_node_count(&client->dev);
-	if (!count) {
-		dev_err(&client->dev, "LEDs are not defined in device tree!");
+	if (!count || count > LM3697_MAX_CONTROL_BANKS) {
+		dev_err(&client->dev, "Strange device tree!");
 		return -ENODEV;
 	}
 
@@ -322,6 +323,7 @@ static int lm3697_probe(struct i2c_client *client,
 
 	led->client = client;
 	led->dev = &client->dev;
+	led->num_banks = count;
 	led->regmap = devm_regmap_init_i2c(client, &lm3697_regmap_config);
 	if (IS_ERR(led->regmap)) {
 		ret = PTR_ERR(led->regmap);
-- 
2.11.0