linux-kernel - Re: w1: Fix w1

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Message-ID: <20120219124820.4a8989f0@notabene.brown>
Date:	Sun, 19 Feb 2012 12:48:20 +1100
From:	NeilBrown <neilb@...e.de>
To:	Dan Carpenter <dan.carpenter@...cle.com>
Cc:	linux-kernel@...r.kernel.org
Subject: Re: w1: Fix w1_bq27000

On Sat, 18 Feb 2012 23:51:25 +0300 Dan Carpenter <dan.carpenter@...cle.com>
wrote:

> Hello NeilBrown,
> 
> This is a semi-automatic email about new static checker warnings.
> 
> The patch 9f3519d2ed26: "w1: Fix w1_bq27000" from Feb 15, 2012, leads 
> to the following Smatch complaint:
> 
> drivers/w1/slaves/w1_bq27000.c:48 w1_bq27000_read()
> 	 warn: variable dereferenced before check 'dev' (see line 46)
> 
> drivers/w1/slaves/w1_bq27000.c
>     45		u8 val;
>     46		struct w1_slave *sl = container_of(dev->parent, struct w1_slave, dev);
>                                                    ^^^^^^^^^^^
> New dereference.
> 
>     47	
>     48		if (!dev)
>                      ^^^
> Old check.
> 
>     49			return 0;
>     50	
> 
> regards,
> dan carpenter

Thanks..
I suspect we should just remove the
   if (!dev)
       return

I should probably get rid of w1_bq27000_write as it is totally unused, and I
need to hold a lock in w1_bq27000_read or I can get really bad things
happening if two threads try to rad the status at the same time.

Ho hum.

Thanks,
NeilBrown

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