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HID: cp2112: fix sleep-while-atomic regression

PATCH Applied Johan Hovold 3 participants 5 messages Jan 30, 2017 – Jan 31, 2017 HID

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Johan Hovold

author
#0 lore raw

cover HID: cp2112: fix sleep-while-atomic regression

These patches fix a sleep-while-atomic and an error-handling issue introduced by a patch that went into 4.9.

Note that this series has only been compile tested.

Johan

Johan Hovold (2):
HID: cp2112: fix sleep-while-atomic
HID: cp2112: fix gpio-callback error handling

 drivers/hid/hid-cp2112.c | 28 ++++++++++++----------------
 1 file changed, 12 insertions(+), 16 deletions(-)
Signature · 1 line
2.10.2
author
#1 lore raw

PATCH 1/2 HID: cp2112: fix sleep-while-atomic

A recent commit fixing DMA-buffers on stack added a shared transfer buffer protected by a spinlock. This is broken as the USB HID request callbacks can sleep. Fix this up by replacing the spinlock with a mutex.

Fixes 1ffb3c40ffb5 ("HID: cp2112: make transfer buffers DMA capable")
Cc stable <[email protected]> # 4.9
Signed-off-by Johan Hovold <[email protected]>
---
 drivers/hid/hid-cp2112.c | 26 +++++++++++---------------
 1 file changed, 11 insertions(+), 15 deletions(-)
drivers/hid/hid-cp2112.c +11 -15
index f31a778b0851..3e0b6bad29f2 100644
@@ -168,7 +168,7 @@ struct cp2112_device {
 	atomic_t xfer_avail;
 	struct gpio_chip gc;
 	u8 *in_out_buffer;
-	spinlock_t lock;
+	struct mutex lock;
 
 	struct gpio_desc *desc[8];
 	bool gpio_poll;

@@ -186,10 +186,9 @@ static int cp2112_gpio_direction_input(struct gpio_chip *chip, unsigned offset)
 	struct cp2112_device *dev = gpiochip_get_data(chip);
 	struct hid_device *hdev = dev->hdev;
 	u8 *buf = dev->in_out_buffer;
-	unsigned long flags;
 	int ret;
 
-	spin_lock_irqsave(&dev->lock, flags);
+	mutex_lock(&dev->lock);
 
 	ret = hid_hw_raw_request(hdev, CP2112_GPIO_CONFIG, buf,
 				 CP2112_GPIO_CONFIG_LENGTH, HID_FEATURE_REPORT,

@@ -213,7 +212,7 @@ static int cp2112_gpio_direction_input(struct gpio_chip *chip, unsigned offset)
 	ret = 0;
 
 exit:
-	spin_unlock_irqrestore(&dev->lock, flags);
+	mutex_unlock(&dev->lock);
 	return ret <= 0 ? ret : -EIO;
 }
 

@@ -222,10 +221,9 @@ static void cp2112_gpio_set(struct gpio_chip *chip, unsigned offset, int value)
 	struct cp2112_device *dev = gpiochip_get_data(chip);
 	struct hid_device *hdev = dev->hdev;
 	u8 *buf = dev->in_out_buffer;
-	unsigned long flags;
 	int ret;
 
-	spin_lock_irqsave(&dev->lock, flags);
+	mutex_lock(&dev->lock);
 
 	buf[0] = CP2112_GPIO_SET;
 	buf[1] = value ? 0xff : 0;

@@ -237,7 +235,7 @@ static void cp2112_gpio_set(struct gpio_chip *chip, unsigned offset, int value)
 	if (ret < 0)
 		hid_err(hdev, "error setting GPIO values: %d\n", ret);
 
-	spin_unlock_irqrestore(&dev->lock, flags);
+	mutex_unlock(&dev->lock);
 }
 
 static int cp2112_gpio_get_all(struct gpio_chip *chip)

@@ -245,10 +243,9 @@ static int cp2112_gpio_get_all(struct gpio_chip *chip)
 	struct cp2112_device *dev = gpiochip_get_data(chip);
 	struct hid_device *hdev = dev->hdev;
 	u8 *buf = dev->in_out_buffer;
-	unsigned long flags;
 	int ret;
 
-	spin_lock_irqsave(&dev->lock, flags);
+	mutex_lock(&dev->lock);
 
 	ret = hid_hw_raw_request(hdev, CP2112_GPIO_GET, buf,
 				 CP2112_GPIO_GET_LENGTH, HID_FEATURE_REPORT,

@@ -262,7 +259,7 @@ static int cp2112_gpio_get_all(struct gpio_chip *chip)
 	ret = buf[1];
 
 exit:
-	spin_unlock_irqrestore(&dev->lock, flags);
+	mutex_unlock(&dev->lock);
 
 	return ret;
 }

@@ -284,10 +281,9 @@ static int cp2112_gpio_direction_output(struct gpio_chip *chip,
 	struct cp2112_device *dev = gpiochip_get_data(chip);
 	struct hid_device *hdev = dev->hdev;
 	u8 *buf = dev->in_out_buffer;
-	unsigned long flags;
 	int ret;
 
-	spin_lock_irqsave(&dev->lock, flags);
+	mutex_lock(&dev->lock);
 
 	ret = hid_hw_raw_request(hdev, CP2112_GPIO_CONFIG, buf,
 				 CP2112_GPIO_CONFIG_LENGTH, HID_FEATURE_REPORT,

@@ -308,7 +304,7 @@ static int cp2112_gpio_direction_output(struct gpio_chip *chip,
 		goto fail;
 	}
 
-	spin_unlock_irqrestore(&dev->lock, flags);
+	mutex_unlock(&dev->lock);
 
 	/*
 	 * Set gpio value when output direction is already set,

@@ -319,7 +315,7 @@ static int cp2112_gpio_direction_output(struct gpio_chip *chip,
 	return 0;
 
 fail:
-	spin_unlock_irqrestore(&dev->lock, flags);
+	mutex_unlock(&dev->lock);
 	return ret < 0 ? ret : -EIO;
 }
 

@@ -1235,7 +1231,7 @@ static int cp2112_probe(struct hid_device *hdev, const struct hid_device_id *id)
 	if (!dev->in_out_buffer)
 		return -ENOMEM;
 
-	spin_lock_init(&dev->lock);
+	mutex_init(&dev->lock);
 
 	ret = hid_parse(hdev);
 	if (ret) {
Signature · 1 line
2.10.2
author
#2 lore raw

PATCH 2/2 HID: cp2112: fix gpio-callback error handling

In case of a zero-length report, the gpio direction_input callback would currently return success instead of an errno.

Fixes 1ffb3c40ffb5 ("HID: cp2112: make transfer buffers DMA capable")
Cc stable <[email protected]> # 4.9
Signed-off-by Johan Hovold <[email protected]>
---
 drivers/hid/hid-cp2112.c | 2 +-
 1 file changed, 1 insertion(+), 1 deletion(-)
drivers/hid/hid-cp2112.c +1 -1
index 3e0b6bad29f2..b22d0f83f8e3 100644
@@ -213,7 +213,7 @@ static int cp2112_gpio_direction_input(struct gpio_chip *chip, unsigned offset)
 
 exit:
 	mutex_unlock(&dev->lock);
-	return ret <= 0 ? ret : -EIO;
+	return ret < 0 ? ret : -EIO;
 }
 
 static void cp2112_gpio_set(struct gpio_chip *chip, unsigned offset, int value)
Signature · 1 line
2.10.2
Reviewed-by on the v1 series
#3 lore raw
In reply to Johan Hovold
Quoted 4 lines · Johan Hovold

These patches fix a sleep-while-atomic and an error-handling issue introduced by a patch that went into 4.9.

Note that this series has only been compile tested.

Tested the series, and:

Reviewed-by Benjamin Tissoires <[email protected]>

Thanks for spotting that!

Cheers,
Benjamin

Quoted 14 lines

Johan

Johan Hovold (2):
HID: cp2112: fix sleep-while-atomic
HID: cp2112: fix gpio-callback error handling

 drivers/hid/hid-cp2112.c | 28 ++++++++++++----------------
 1 file changed, 12 insertions(+), 16 deletions(-)
Signature · 1 line
2.10.2
maintainer Applied
#4 lore raw
In reply to Johan Hovold
Quoted 2 lines · Johan Hovold

These patches fix a sleep-while-atomic and an error-handling issue introduced by a patch that went into 4.9.

Applied, thanks a lot for fixing this up.

Signature · 2 lines
Jiri Kosina
SUSE Labs