Re: rtc: RV8803: BUG: scheduling while atomic

On Wednesday, February 3, 2016 at 12:07:47 PM UTC+1, Alexandre Belloni 
wrote:
>
> Hi, 
>
> On 03/02/2016 at 01:31:21 -0800, dirk....@gmail.com <javascript:> wrote : 
> > Testing the RV8803 driver [1] we are getting several "BUG: scheduling 
> while 
> > atomic" [2]. 
> > 
> > Having a quick look this might be from rv8803_set_time() holding a 
> spinlock 
> > during the call to i2c_smbus_read_byte_data()? 
> > 
> > Any ideas? 
> > 
>
> Yes, that is probably the case. As this is already a threaded irq, it 
> can probably be changed into a mutex this would solve the issue.
>

Anything like below [1]?

If you like this, we'll test it.

Many thanks

Dirk

[1]

 
@@ -102,7 +102,7 @@ static irqreturn_t rv8803_handle_irq(int irq, void 
*dev_id)
                       rv8803->ctrl);
     }
 
-    spin_unlock(&rv8803->flags_lock);
+    mutex_unlock(&rv8803->flags_lock);
 
     return IRQ_HANDLED;
 }
@@ -155,7 +155,6 @@ static int rv8803_set_time(struct device *dev, struct 
rtc_time *tm)
     struct rv8803_data *rv8803 = dev_get_drvdata(dev);
     u8 date[7];
     int flags, ret;
-    unsigned long irqflags;
 
     if ((tm->tm_year < 100) || (tm->tm_year > 199))
         return -EINVAL;
@@ -173,18 +172,18 @@ static int rv8803_set_time(struct device *dev, struct 
rtc_time *tm)
     if (ret < 0)
         return ret;
 
-    spin_lock_irqsave(&rv8803->flags_lock, irqflags);
+    mutex_lock(&rv8803->flags_lock);
 
     flags = i2c_smbus_read_byte_data(rv8803->client, RV8803_FLAG);
     if (flags < 0) {
-        spin_unlock_irqrestore(&rv8803->flags_lock, irqflags);
+        mutex_unlock(&rv8803->flags_lock);
         return flags;
     }
 
     ret = i2c_smbus_write_byte_data(rv8803->client, RV8803_FLAG,
                     flags & ~RV8803_FLAG_V2F);
 
-    spin_unlock_irqrestore(&rv8803->flags_lock, irqflags);
+    mutex_unlock(&rv8803->flags_lock);
 
     return ret;
 }
@@ -226,7 +225,7 @@ static int rv8803_set_alarm(struct device *dev, struct 
rtc_wkalrm *alrm)
     u8 alarmvals[3];
     u8 ctrl[2];
     int ret, err;
-    unsigned long alarm_time, irqflags;
+    unsigned long alarm_time;
 
     /* The alarm has no seconds, round up to nearest minute */
     if (alrm->time.tm_sec) {
@@ -236,11 +235,11 @@ static int rv8803_set_alarm(struct device *dev, 
struct rtc_wkalrm *alrm)
         rtc_time_to_tm(alarm_time, &alrm->time);
     }
 
-    spin_lock_irqsave(&rv8803->flags_lock, irqflags);
+    mutex_lock(&rv8803->flags_lock);
 
     ret = i2c_smbus_read_i2c_block_data(client, RV8803_FLAG, 2, ctrl);
     if (ret != 2) {
-        spin_unlock_irqrestore(&rv8803->flags_lock, irqflags);
+        mutex_unlock(&rv8803->flags_lock);
         return ret < 0 ? ret : -EIO;
     }
 
@@ -253,14 +252,14 @@ static int rv8803_set_alarm(struct device *dev, 
struct rtc_wkalrm *alrm)
         err = i2c_smbus_write_byte_data(rv8803->client, RV8803_CTRL,
                         rv8803->ctrl);
         if (err) {
-            spin_unlock_irqrestore(&rv8803->flags_lock, irqflags);
+            mutex_unlock(&rv8803->flags_lock);
             return err;
         }
     }
 
     ctrl[1] &= ~RV8803_FLAG_AF;
     err = i2c_smbus_write_byte_data(rv8803->client, RV8803_FLAG, ctrl[1]);
-    spin_unlock_irqrestore(&rv8803->flags_lock, irqflags);
+    mutex_unlock(&rv8803->flags_lock);
     if (err)
         return err;
 
@@ -289,7 +288,6 @@ static int rv8803_alarm_irq_enable(struct device *dev, 
unsigned int enabled)
     struct i2c_client *client = to_i2c_client(dev);
     struct rv8803_data *rv8803 = dev_get_drvdata(dev);
     int ctrl, flags, err;
-    unsigned long irqflags;
 
     ctrl = rv8803->ctrl;
 
@@ -305,15 +303,15 @@ static int rv8803_alarm_irq_enable(struct device 
*dev, unsigned int enabled)
             ctrl &= ~RV8803_CTRL_AIE;
     }
 
-    spin_lock_irqsave(&rv8803->flags_lock, irqflags);
+    mutex_lock(&rv8803->flags_lock);
     flags = i2c_smbus_read_byte_data(client, RV8803_FLAG);
     if (flags < 0) {
-        spin_unlock_irqrestore(&rv8803->flags_lock, irqflags);
+        mutex_unlock(&rv8803->flags_lock);
         return flags;
     }
     flags &= ~(RV8803_FLAG_AF | RV8803_FLAG_UF);
     err = i2c_smbus_write_byte_data(client, RV8803_FLAG, flags);
-    spin_unlock_irqrestore(&rv8803->flags_lock, irqflags);
+    mutex_unlock(&rv8803->flags_lock);
     if (err)
         return err;
 
@@ -333,7 +331,6 @@ static int rv8803_ioctl(struct device *dev, unsigned 
int cmd, unsigned long arg)
     struct i2c_client *client = to_i2c_client(dev);
     struct rv8803_data *rv8803 = dev_get_drvdata(dev);
     int flags, ret = 0;
-    unsigned long irqflags;
 
     switch (cmd) {
     case RTC_VL_READ:
@@ -355,16 +352,16 @@ static int rv8803_ioctl(struct device *dev, unsigned 
int cmd, unsigned long arg)
         return 0;
 
     case RTC_VL_CLR:
-        spin_lock_irqsave(&rv8803->flags_lock, irqflags);
+        mutex_lock(&rv8803->flags_lock);
         flags = i2c_smbus_read_byte_data(client, RV8803_FLAG);
         if (flags < 0) {
-            spin_unlock_irqrestore(&rv8803->flags_lock, irqflags);
+            mutex_unlock(&rv8803->flags_lock);
             return flags;
         }
 
         flags &= ~(RV8803_FLAG_V1F | RV8803_FLAG_V2F);
         ret = i2c_smbus_write_byte_data(client, RV8803_FLAG, flags);
-        spin_unlock_irqrestore(&rv8803->flags_lock, irqflags);
+        mutex_unlock(&rv8803->flags_lock);
         if (ret < 0)
             return ret;
 
@@ -441,6 +438,7 @@ static int rv8803_probe(struct i2c_client *client,
     if (!rv8803)
         return -ENOMEM;
 
+    mutex_init(&rv8803->flags_lock);
     rv8803->client = client;
     i2c_set_clientdata(client, rv8803);

On 03/02/2016 at 04:58:53 -0800, dirk.behme@gmail.com wrote :
> Anything like below [1]?
> 
> If you like this, we'll test it.
> 

This seems ok to me.

> Many thanks
> 
> Dirk
> 
> [1]
> 
> diff --git a/drivers/rtc/rtc-rv8803.c b/drivers/rtc/rtc-rv8803.c
> index 33c7e2a..38621ff 100644
> --- a/drivers/rtc/rtc-rv8803.c
> +++ b/drivers/rtc/rtc-rv8803.c
> @@ -52,7 +52,7 @@
>  struct rv8803_data {
>      struct i2c_client *client;
>      struct rtc_device *rtc;
> -    spinlock_t flags_lock;
> +    struct mutex flags_lock;
>      u8 ctrl;
>  };
>  
> @@ -63,11 +63,11 @@ static irqreturn_t rv8803_handle_irq(int irq, void 
> *dev_id)
>      unsigned long events = 0;
>      u8 flags;
>  
> -    spin_lock(&rv8803->flags_lock);
> +    mutex_lock(&rv8803->flags_lock);
>  
>      flags = i2c_smbus_read_byte_data(client, RV8803_FLAG);
>      if (flags <= 0) {
> -        spin_unlock(&rv8803->flags_lock);
> +        mutex_unlock(&rv8803->flags_lock);
>          return IRQ_NONE;
>      }
>  
> @@ -102,7 +102,7 @@ static irqreturn_t rv8803_handle_irq(int irq, void 
> *dev_id)
>                        rv8803->ctrl);
>      }
>  
> -    spin_unlock(&rv8803->flags_lock);
> +    mutex_unlock(&rv8803->flags_lock);
>  
>      return IRQ_HANDLED;
>  }
> @@ -155,7 +155,6 @@ static int rv8803_set_time(struct device *dev, struct 
> rtc_time *tm)
>      struct rv8803_data *rv8803 = dev_get_drvdata(dev);
>      u8 date[7];
>      int flags, ret;
> -    unsigned long irqflags;
>  
>      if ((tm->tm_year < 100) || (tm->tm_year > 199))
>          return -EINVAL;
> @@ -173,18 +172,18 @@ static int rv8803_set_time(struct device *dev, struct 
> rtc_time *tm)
>      if (ret < 0)
>          return ret;
>  
> -    spin_lock_irqsave(&rv8803->flags_lock, irqflags);
> +    mutex_lock(&rv8803->flags_lock);
>  
>      flags = i2c_smbus_read_byte_data(rv8803->client, RV8803_FLAG);
>      if (flags < 0) {
> -        spin_unlock_irqrestore(&rv8803->flags_lock, irqflags);
> +        mutex_unlock(&rv8803->flags_lock);
>          return flags;
>      }
>  
>      ret = i2c_smbus_write_byte_data(rv8803->client, RV8803_FLAG,
>                      flags & ~RV8803_FLAG_V2F);
>  
> -    spin_unlock_irqrestore(&rv8803->flags_lock, irqflags);
> +    mutex_unlock(&rv8803->flags_lock);
>  
>      return ret;
>  }
> @@ -226,7 +225,7 @@ static int rv8803_set_alarm(struct device *dev, struct 
> rtc_wkalrm *alrm)
>      u8 alarmvals[3];
>      u8 ctrl[2];
>      int ret, err;
> -    unsigned long alarm_time, irqflags;
> +    unsigned long alarm_time;
>  
>      /* The alarm has no seconds, round up to nearest minute */
>      if (alrm->time.tm_sec) {
> @@ -236,11 +235,11 @@ static int rv8803_set_alarm(struct device *dev, 
> struct rtc_wkalrm *alrm)
>          rtc_time_to_tm(alarm_time, &alrm->time);
>      }
>  
> -    spin_lock_irqsave(&rv8803->flags_lock, irqflags);
> +    mutex_lock(&rv8803->flags_lock);
>  
>      ret = i2c_smbus_read_i2c_block_data(client, RV8803_FLAG, 2, ctrl);
>      if (ret != 2) {
> -        spin_unlock_irqrestore(&rv8803->flags_lock, irqflags);
> +        mutex_unlock(&rv8803->flags_lock);
>          return ret < 0 ? ret : -EIO;
>      }
>  
> @@ -253,14 +252,14 @@ static int rv8803_set_alarm(struct device *dev, 
> struct rtc_wkalrm *alrm)
>          err = i2c_smbus_write_byte_data(rv8803->client, RV8803_CTRL,
>                          rv8803->ctrl);
>          if (err) {
> -            spin_unlock_irqrestore(&rv8803->flags_lock, irqflags);
> +            mutex_unlock(&rv8803->flags_lock);
>              return err;
>          }
>      }
>  
>      ctrl[1] &= ~RV8803_FLAG_AF;
>      err = i2c_smbus_write_byte_data(rv8803->client, RV8803_FLAG, ctrl[1]);
> -    spin_unlock_irqrestore(&rv8803->flags_lock, irqflags);
> +    mutex_unlock(&rv8803->flags_lock);
>      if (err)
>          return err;
>  
> @@ -289,7 +288,6 @@ static int rv8803_alarm_irq_enable(struct device *dev, 
> unsigned int enabled)
>      struct i2c_client *client = to_i2c_client(dev);
>      struct rv8803_data *rv8803 = dev_get_drvdata(dev);
>      int ctrl, flags, err;
> -    unsigned long irqflags;
>  
>      ctrl = rv8803->ctrl;
>  
> @@ -305,15 +303,15 @@ static int rv8803_alarm_irq_enable(struct device 
> *dev, unsigned int enabled)
>              ctrl &= ~RV8803_CTRL_AIE;
>      }
>  
> -    spin_lock_irqsave(&rv8803->flags_lock, irqflags);
> +    mutex_lock(&rv8803->flags_lock);
>      flags = i2c_smbus_read_byte_data(client, RV8803_FLAG);
>      if (flags < 0) {
> -        spin_unlock_irqrestore(&rv8803->flags_lock, irqflags);
> +        mutex_unlock(&rv8803->flags_lock);
>          return flags;
>      }
>      flags &= ~(RV8803_FLAG_AF | RV8803_FLAG_UF);
>      err = i2c_smbus_write_byte_data(client, RV8803_FLAG, flags);
> -    spin_unlock_irqrestore(&rv8803->flags_lock, irqflags);
> +    mutex_unlock(&rv8803->flags_lock);
>      if (err)
>          return err;
>  
> @@ -333,7 +331,6 @@ static int rv8803_ioctl(struct device *dev, unsigned 
> int cmd, unsigned long arg)
>      struct i2c_client *client = to_i2c_client(dev);
>      struct rv8803_data *rv8803 = dev_get_drvdata(dev);
>      int flags, ret = 0;
> -    unsigned long irqflags;
>  
>      switch (cmd) {
>      case RTC_VL_READ:
> @@ -355,16 +352,16 @@ static int rv8803_ioctl(struct device *dev, unsigned 
> int cmd, unsigned long arg)
>          return 0;
>  
>      case RTC_VL_CLR:
> -        spin_lock_irqsave(&rv8803->flags_lock, irqflags);
> +        mutex_lock(&rv8803->flags_lock);
>          flags = i2c_smbus_read_byte_data(client, RV8803_FLAG);
>          if (flags < 0) {
> -            spin_unlock_irqrestore(&rv8803->flags_lock, irqflags);
> +            mutex_unlock(&rv8803->flags_lock);
>              return flags;
>          }
>  
>          flags &= ~(RV8803_FLAG_V1F | RV8803_FLAG_V2F);
>          ret = i2c_smbus_write_byte_data(client, RV8803_FLAG, flags);
> -        spin_unlock_irqrestore(&rv8803->flags_lock, irqflags);
> +        mutex_unlock(&rv8803->flags_lock);
>          if (ret < 0)
>              return ret;
>  
> @@ -441,6 +438,7 @@ static int rv8803_probe(struct i2c_client *client,
>      if (!rv8803)
>          return -ENOMEM;
>  
> +    mutex_init(&rv8803->flags_lock);
>      rv8803->client = client;
>      i2c_set_clientdata(client, rv8803);
>  
> 
> 
> 
>