[PATCH] rtc: pcf2127: fix uninitialized variable msg

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[PATCH] rtc: pcf2127: fix uninitialized variable msg

Biwen Li (OSS)
From: Biwen Li <[hidden email]>

Fix uninitialized variable msg

Signed-off-by: Biwen Li <[hidden email]>
---
 drivers/rtc/pcf2127.c | 3 ++-
 1 file changed, 2 insertions(+), 1 deletion(-)

diff --git a/drivers/rtc/pcf2127.c b/drivers/rtc/pcf2127.c
index f695350..58c4ee9 100644
--- a/drivers/rtc/pcf2127.c
+++ b/drivers/rtc/pcf2127.c
@@ -1,6 +1,7 @@
 /*
  * Copyright (C) 2016 by NXP Semiconductors Inc.
  * Date & Time support for PCF2127 RTC
+ * Copyright 2020 NXP
  */
 
 /* #define DEBUG */
@@ -26,7 +27,7 @@ static int pcf2127_read_reg(struct udevice *dev, uint offset,
     u8 *buffer, int len)
 {
  struct dm_i2c_chip *chip = dev_get_parent_platdata(dev);
- struct i2c_msg msg;
+ struct i2c_msg msg = {0};
  int ret;
 
  /* Set the address of the start register to be read */
--
2.7.4

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Re: [PATCH] rtc: pcf2127: fix uninitialized variable msg

Rasmus Villemoes
On 09/07/2020 12.58, Biwen Li wrote:

> From: Biwen Li <[hidden email]>
>
> Fix uninitialized variable msg
>
>   struct dm_i2c_chip *chip = dev_get_parent_platdata(dev);
> - struct i2c_msg msg;
> + struct i2c_msg msg = {0};
>   int ret;
>  
>   /* Set the address of the start register to be read */
>

I assume it's the

        msg.flags |= I2C_M_RD;

line that is warned about (please include such info)? Isn't the right
fix to replace that by

        msg.flags = I2C_M_RD;

?

Rasmus
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RE: [EXT] Re: [PATCH] rtc: pcf2127: fix uninitialized variable msg

Biwen Li
>
> On 09/07/2020 12.58, Biwen Li wrote:
> > From: Biwen Li <[hidden email]>
> >
> > Fix uninitialized variable msg
> >
> >       struct dm_i2c_chip *chip = dev_get_parent_platdata(dev);
> > -     struct i2c_msg msg;
> > +     struct i2c_msg msg = {0};
> >       int ret;
> >
> >       /* Set the address of the start register to be read */
> >
>
> I assume it's the
>
>         msg.flags |= I2C_M_RD;
>
> line that is warned about (please include such info)? Isn't the right fix to
> replace that by
>
>         msg.flags = I2C_M_RD;
>
> ?
Two lines("struct i2c msg;" and "msg.flags |= I2C_M_RD") are warned by build system. Initializing msg variable will be better.
>
> Rasmus
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Re: [EXT] Re: [PATCH] rtc: pcf2127: fix uninitialized variable msg

Rasmus Villemoes
On 09/07/2020 13.38, Biwen Li wrote:

>>
>> On 09/07/2020 12.58, Biwen Li wrote:
>>> From: Biwen Li <[hidden email]>
>>>
>>> Fix uninitialized variable msg
>>>
>>>       struct dm_i2c_chip *chip = dev_get_parent_platdata(dev);
>>> -     struct i2c_msg msg;
>>> +     struct i2c_msg msg = {0};
>>>       int ret;
>>>
>>>       /* Set the address of the start register to be read */
>>>
>>
>> I assume it's the
>>
>>         msg.flags |= I2C_M_RD;
>>
>> line that is warned about (please include such info)? Isn't the right fix to
>> replace that by
>>
>>         msg.flags = I2C_M_RD;
>>
>> ?
> Two lines("struct i2c msg;" and "msg.flags |= I2C_M_RD") are warned by build system.

What? That doesn't make sense. Perhaps your compiler is just friendly
enough to show you the declaration of the struct i2c_msg, but clearly
declaring an automatic variable without initializing it is not, by
itself, wrong. Otherwise "int ret;" in that very same function should be
warned about, and 100000 other instances in any code base written in C.

Please show the exact output from the compiler and the compiler version.

> Initializing msg variable will be better.

No, understanding the cause of the warning and fixing that is clearly
better.

Rasmus
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RE: [EXT] Re: [PATCH] rtc: pcf2127: fix uninitialized variable msg

Biwen Li (OSS)
>
> On 09/07/2020 13.38, Biwen Li wrote:
> >>
> >> On 09/07/2020 12.58, Biwen Li wrote:
> >>> From: Biwen Li <[hidden email]>
> >>>
> >>> Fix uninitialized variable msg
> >>>
> >>>       struct dm_i2c_chip *chip = dev_get_parent_platdata(dev);
> >>> -     struct i2c_msg msg;
> >>> +     struct i2c_msg msg = {0};
> >>>       int ret;
> >>>
> >>>       /* Set the address of the start register to be read */
> >>>
> >>
> >> I assume it's the
> >>
> >>         msg.flags |= I2C_M_RD;
> >>
> >> line that is warned about (please include such info)? Isn't the right
> >> fix to replace that by
> >>
> >>         msg.flags = I2C_M_RD;
> >>
> >> ?
> > Two lines("struct i2c msg;" and "msg.flags |= I2C_M_RD") are warned by
> build system.
>
> What? That doesn't make sense. Perhaps your compiler is just friendly enough
> to show you the declaration of the struct i2c_msg, but clearly declaring an
> automatic variable without initializing it is not, by itself, wrong. Otherwise "int
> ret;" in that very same function should be warned about, and 100000 other
> instances in any code base written in C.
>
> Please show the exact output from the compiler and the compiler version.
Sorry, acctually not build system. It's code analysis tool.
Such as:
Declaring variable msg without initializer. (struce i2c_msg msg;)
Uninitialized scalar variable (UNINIT),  uninit_use: Using uninitialized value msg.flags.(msg.flags |= I2C_M_RD)
>
> > Initializing msg variable will be better.
>
> No, understanding the cause of the warning and fixing that is clearly better.
>
> Rasmus
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RE: [EXT] Re: [PATCH] rtc: pcf2127: fix uninitialized variable msg

Priyanka Jain (OSS)
>-----Original Message-----
>From: U-Boot <[hidden email]> On Behalf Of Biwen Li (OSS)
>Sent: Friday, July 10, 2020 7:24 AM
>To: Rasmus Villemoes <[hidden email]>; Biwen Li (OSS)
><[hidden email]>; Jagdish Gediya <[hidden email]>; Priyanka
>Jain <[hidden email]>
>Cc: Jiafei Pan <[hidden email]>; [hidden email]
>Subject: RE: [EXT] Re: [PATCH] rtc: pcf2127: fix uninitialized variable msg
>
>>
>> On 09/07/2020 13.38, Biwen Li wrote:
>> >>
>> >> On 09/07/2020 12.58, Biwen Li wrote:
>> >>> From: Biwen Li <[hidden email]>
>> >>>
>> >>> Fix uninitialized variable msg
>> >>>
>> >>>       struct dm_i2c_chip *chip = dev_get_parent_platdata(dev);
>> >>> -     struct i2c_msg msg;
>> >>> +     struct i2c_msg msg = {0};
>> >>>       int ret;
>> >>>
>> >>>       /* Set the address of the start register to be read */
>> >>>
>> >>
>> >> I assume it's the
>> >>
>> >>         msg.flags |= I2C_M_RD;
>> >>
>> >> line that is warned about (please include such info)? Isn't the
>> >> right fix to replace that by
>> >>
>> >>         msg.flags = I2C_M_RD;
>> >>
>> >> ?
>> > Two lines("struct i2c msg;" and "msg.flags |= I2C_M_RD") are warned
>> > by
>> build system.
>>
>> What? That doesn't make sense. Perhaps your compiler is just friendly
>> enough to show you the declaration of the struct i2c_msg, but clearly
>> declaring an automatic variable without initializing it is not, by
>> itself, wrong. Otherwise "int ret;" in that very same function should
>> be warned about, and 100000 other instances in any code base written in C.
>>
>> Please show the exact output from the compiler and the compiler version.
>Sorry, acctually not build system. It's code analysis tool.

Can you please update subject or description stating that you are fixing issue reported by static analysis tool coverity

Thanks
Priyanka

>Such as:
>Declaring variable msg without initializer. (struce i2c_msg msg;) Uninitialized
>scalar variable (UNINIT),  uninit_use: Using uninitialized value
>msg.flags.(msg.flags |= I2C_M_RD)
>>
>> > Initializing msg variable will be better.
>>
>> No, understanding the cause of the warning and fixing that is clearly better.
>>
>> Rasmus