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backlight: adp88x0: fix uninitialized variable use

PATCH Applied Arnd Bergmann 3 participants 4 messages Nov 23, 2015

Subsystems (3)
Framebuffer layer Backlight class/subsystem ADP8860 backlight driver (ADP8860/ADP8861/ADP8863)
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Arnd Bergmann

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#0 lore raw

PATCH 1/1 backlight: adp88x0: fix uninitialized variable use

gcc correctly warns about both the adp8860 and adp8870 backlight drivers using an uninitialized variable in their error handling path:

drivers/video/backlight/adp8870_bl.c: In function 'adp8870_bl_ambient_light_zone_store':
drivers/video/backlight/adp8870_bl.c:811:11: warning: 'reg_val' may be used uninitialized in this function

This changes the code to only write back the data if it was correctly read to start with.

As a side-note, the drivers are mostly identical, so I think they should really be merged into one file to avoid having to fix every bug twice.

Signed-off-by Arnd Bergmann <[email protected]>
drivers/video/backlight/adp8860_bl.c +6 -4
index 98ffe71e8af2..f0d4c0324580 100644
@@ -621,10 +621,12 @@ static ssize_t adp8860_bl_ambient_light_zone_store(struct device *dev,
 
 		/* Set user supplied ambient light zone */
 		mutex_lock(&data->lock);
-		adp8860_read(data->client, ADP8860_CFGR, &reg_val);
-		reg_val &= ~(CFGR_BLV_MASK << CFGR_BLV_SHIFT);
-		reg_val |= (val - 1) << CFGR_BLV_SHIFT;
-		adp8860_write(data->client, ADP8860_CFGR, reg_val);
+		ret = adp8860_read(data->client, ADP8860_CFGR, &reg_val);
+		if (!ret) {
+			reg_val &= ~(CFGR_BLV_MASK << CFGR_BLV_SHIFT);
+			reg_val |= (val - 1) << CFGR_BLV_SHIFT;
+			adp8860_write(data->client, ADP8860_CFGR, reg_val);
+		}
 		mutex_unlock(&data->lock);
 	}
drivers/video/backlight/adp8870_bl.c +6 -4
index 9d738352d7d4..21acac90fd77 100644
@@ -807,10 +807,12 @@ static ssize_t adp8870_bl_ambient_light_zone_store(struct device *dev,
 
 		/* Set user supplied ambient light zone */
 		mutex_lock(&data->lock);
-		adp8870_read(data->client, ADP8870_CFGR, &reg_val);
-		reg_val &= ~(CFGR_BLV_MASK << CFGR_BLV_SHIFT);
-		reg_val |= (val - 1) << CFGR_BLV_SHIFT;
-		adp8870_write(data->client, ADP8870_CFGR, reg_val);
+		ret = adp8870_read(data->client, ADP8870_CFGR, &reg_val);
+		if (!ret) {
+			reg_val &= ~(CFGR_BLV_MASK << CFGR_BLV_SHIFT);
+			reg_val |= (val - 1) << CFGR_BLV_SHIFT;
+			adp8870_write(data->client, ADP8870_CFGR, reg_val);
+		}
 		mutex_unlock(&data->lock);
 	}
maintainer Acked-by on v1 1/1
#1 lore raw
Quoted 7 lines · Arnd Bergmann

gcc correctly warns about both the adp8860 and adp8870 backlight drivers using an uninitialized variable in their error handling path:

drivers/video/backlight/adp8870_bl.c: In function 'adp8870_bl_ambient_light_zone_store':
drivers/video/backlight/adp8870_bl.c:811:11: warning: 'reg_val' may be used uninitialized in this function

Quoted 8 lines

This changes the code to only write back the data if it was correctly read to start with.

As a side-note, the drivers are mostly identical, so I think they should really be merged into one file to avoid having to fix every bug twice.

Signed-off-by Arnd Bergmann <[email protected]>
Acked-by Michael Hennerich <[email protected]>
Quoted 44 lines
drivers/video/backlight/adp8860_bl.c +6 -4
index 98ffe71e8af2..f0d4c0324580 100644
@@ -621,10 +621,12 @@ static ssize_t adp8860_bl_ambient_light_zone_store(struct device *dev,
 
  		/* Set user supplied ambient light zone */
  		mutex_lock(&data->lock);
-		adp8860_read(data->client, ADP8860_CFGR, &reg_val);
-		reg_val &= ~(CFGR_BLV_MASK << CFGR_BLV_SHIFT);
-		reg_val |= (val - 1) << CFGR_BLV_SHIFT;
-		adp8860_write(data->client, ADP8860_CFGR, reg_val);
+		ret = adp8860_read(data->client, ADP8860_CFGR, &reg_val);
+		if (!ret) {
+			reg_val &= ~(CFGR_BLV_MASK << CFGR_BLV_SHIFT);
+			reg_val |= (val - 1) << CFGR_BLV_SHIFT;
+			adp8860_write(data->client, ADP8860_CFGR, reg_val);
+		}
  		mutex_unlock(&data->lock);
  	}
drivers/video/backlight/adp8870_bl.c +6 -4
index 9d738352d7d4..21acac90fd77 100644
@@ -807,10 +807,12 @@ static ssize_t adp8870_bl_ambient_light_zone_store(struct device *dev,
 
  		/* Set user supplied ambient light zone */
  		mutex_lock(&data->lock);
-		adp8870_read(data->client, ADP8870_CFGR, &reg_val);
-		reg_val &= ~(CFGR_BLV_MASK << CFGR_BLV_SHIFT);
-		reg_val |= (val - 1) << CFGR_BLV_SHIFT;
-		adp8870_write(data->client, ADP8870_CFGR, reg_val);
+		ret = adp8870_read(data->client, ADP8870_CFGR, &reg_val);
+		if (!ret) {
+			reg_val &= ~(CFGR_BLV_MASK << CFGR_BLV_SHIFT);
+			reg_val |= (val - 1) << CFGR_BLV_SHIFT;
+			adp8870_write(data->client, ADP8870_CFGR, reg_val);
+		}
  		mutex_unlock(&data->lock);
  	}
Signature · 8 lines
Greetings,
Michael

--
Analog Devices GmbH      Wilhelm-Wagenfeld-Str. 6      80807 Muenchen
Sitz der Gesellschaft: Muenchen; Registergericht: Muenchen HRB 40368;
Geschaeftsfuehrer:Dr.Carsten Suckrow, Thomas Wessel, William A. Martin,
Margaret Seif
Applied
#2 lore raw
In reply to Arnd Bergmann
Quoted 7 lines · Arnd Bergmann

gcc correctly warns about both the adp8860 and adp8870 backlight drivers using an uninitialized variable in their error handling path:

drivers/video/backlight/adp8870_bl.c: In function 'adp8870_bl_ambient_light_zone_store':
drivers/video/backlight/adp8870_bl.c:811:11: warning: 'reg_val' may be used uninitialized in this function

Quoted 8 lines

This changes the code to only write back the data if it was correctly read to start with.

As a side-note, the drivers are mostly identical, so I think they should really be merged into one file to avoid having to fix every bug twice.

Signed-off-by Arnd Bergmann <[email protected]>

Applied, thanks.

Quoted 43 lines
drivers/video/backlight/adp8860_bl.c +6 -4
index 98ffe71e8af2..f0d4c0324580 100644
@@ -621,10 +621,12 @@ static ssize_t adp8860_bl_ambient_light_zone_store(struct device *dev,
 
 		/* Set user supplied ambient light zone */
 		mutex_lock(&data->lock);
-		adp8860_read(data->client, ADP8860_CFGR, &reg_val);
-		reg_val &= ~(CFGR_BLV_MASK << CFGR_BLV_SHIFT);
-		reg_val |= (val - 1) << CFGR_BLV_SHIFT;
-		adp8860_write(data->client, ADP8860_CFGR, reg_val);
+		ret = adp8860_read(data->client, ADP8860_CFGR, &reg_val);
+		if (!ret) {
+			reg_val &= ~(CFGR_BLV_MASK << CFGR_BLV_SHIFT);
+			reg_val |= (val - 1) << CFGR_BLV_SHIFT;
+			adp8860_write(data->client, ADP8860_CFGR, reg_val);
+		}
 		mutex_unlock(&data->lock);
 	}
drivers/video/backlight/adp8870_bl.c +6 -4
index 9d738352d7d4..21acac90fd77 100644
@@ -807,10 +807,12 @@ static ssize_t adp8870_bl_ambient_light_zone_store(struct device *dev,
 
 		/* Set user supplied ambient light zone */
 		mutex_lock(&data->lock);
-		adp8870_read(data->client, ADP8870_CFGR, &reg_val);
-		reg_val &= ~(CFGR_BLV_MASK << CFGR_BLV_SHIFT);
-		reg_val |= (val - 1) << CFGR_BLV_SHIFT;
-		adp8870_write(data->client, ADP8870_CFGR, reg_val);
+		ret = adp8870_read(data->client, ADP8870_CFGR, &reg_val);
+		if (!ret) {
+			reg_val &= ~(CFGR_BLV_MASK << CFGR_BLV_SHIFT);
+			reg_val |= (val - 1) << CFGR_BLV_SHIFT;
+			adp8870_write(data->client, ADP8870_CFGR, reg_val);
+		}
 		mutex_unlock(&data->lock);
 	}
Signature · 4 lines
Lee Jones
Linaro STMicroelectronics Landing Team Lead
Linaro.org ? Open source software for ARM SoCs
Follow Linaro: Facebook | Twitter | Blog
#3 lore raw
In reply to Arnd Bergmann
Quoted 7 lines · Arnd Bergmann

gcc correctly warns about both the adp8860 and adp8870 backlight drivers using an uninitialized variable in their error handling path:

drivers/video/backlight/adp8870_bl.c: In function 'adp8870_bl_ambient_light_zone_store':
drivers/video/backlight/adp8870_bl.c:811:11: warning: 'reg_val' may be used uninitialized in this function

Quoted 8 lines

This changes the code to only write back the data if it was correctly read to start with.

As a side-note, the drivers are mostly identical, so I think they should really be merged into one file to avoid having to fix every bug twice.

Signed-off-by Arnd Bergmann <[email protected]>

Applied with the $SUBJECT line fixed.

Quoted 43 lines
drivers/video/backlight/adp8860_bl.c +6 -4
index 98ffe71e8af2..f0d4c0324580 100644
@@ -621,10 +621,12 @@ static ssize_t adp8860_bl_ambient_light_zone_store(struct device *dev,
 
 		/* Set user supplied ambient light zone */
 		mutex_lock(&data->lock);
-		adp8860_read(data->client, ADP8860_CFGR, &reg_val);
-		reg_val &= ~(CFGR_BLV_MASK << CFGR_BLV_SHIFT);
-		reg_val |= (val - 1) << CFGR_BLV_SHIFT;
-		adp8860_write(data->client, ADP8860_CFGR, reg_val);
+		ret = adp8860_read(data->client, ADP8860_CFGR, &reg_val);
+		if (!ret) {
+			reg_val &= ~(CFGR_BLV_MASK << CFGR_BLV_SHIFT);
+			reg_val |= (val - 1) << CFGR_BLV_SHIFT;
+			adp8860_write(data->client, ADP8860_CFGR, reg_val);
+		}
 		mutex_unlock(&data->lock);
 	}
drivers/video/backlight/adp8870_bl.c +6 -4
index 9d738352d7d4..21acac90fd77 100644
@@ -807,10 +807,12 @@ static ssize_t adp8870_bl_ambient_light_zone_store(struct device *dev,
 
 		/* Set user supplied ambient light zone */
 		mutex_lock(&data->lock);
-		adp8870_read(data->client, ADP8870_CFGR, &reg_val);
-		reg_val &= ~(CFGR_BLV_MASK << CFGR_BLV_SHIFT);
-		reg_val |= (val - 1) << CFGR_BLV_SHIFT;
-		adp8870_write(data->client, ADP8870_CFGR, reg_val);
+		ret = adp8870_read(data->client, ADP8870_CFGR, &reg_val);
+		if (!ret) {
+			reg_val &= ~(CFGR_BLV_MASK << CFGR_BLV_SHIFT);
+			reg_val |= (val - 1) << CFGR_BLV_SHIFT;
+			adp8870_write(data->client, ADP8870_CFGR, reg_val);
+		}
 		mutex_unlock(&data->lock);
 	}
Signature · 4 lines
Lee Jones
Linaro STMicroelectronics Landing Team Lead
Linaro.org ? Open source software for ARM SoCs
Follow Linaro: Facebook | Twitter | Blog