linux-kernel - Re: [PATCH 1/1] tty: vt: Remove redundant null check before kfree.

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Date:	Wed, 21 Nov 2012 23:43:34 +0100
From:	Jiri Slaby <jslaby@...e.cz>
To:	Greg KH <gregkh@...uxfoundation.org>
CC:	Sachin Kamat <sachin.kamat@...aro.org>,
	linux-kernel@...r.kernel.org, patches@...aro.org
Subject: Re: [PATCH 1/1] tty: vt: Remove redundant null check before kfree.

On 11/21/2012 03:46 PM, Greg KH wrote:
> On Wed, Nov 21, 2012 at 10:49:07AM +0530, Sachin Kamat wrote:
>> --- a/drivers/tty/vt/consolemap.c
>> +++ b/drivers/tty/vt/consolemap.c
>> @@ -410,10 +410,8 @@ static void con_release_unimap(struct uni_pagedir *p)
>>  		kfree(p->inverse_translations[i]);
>>  		p->inverse_translations[i] = NULL;
>>  	}
>> -	if (p->inverse_trans_unicode) {
>> -		kfree(p->inverse_trans_unicode);
>> -		p->inverse_trans_unicode = NULL;
>> -	}
>> +	kfree(p->inverse_trans_unicode);
>> +	p->inverse_trans_unicode = NULL;
> 
> kfree with NULL is a no-op, but the line after that just caused a kernel
> crash if it was NULL, so I can't accept this type of thing.

Greg, I'm not sure -- what do you mean here? The change actually looks
fine to me... We do not dereference p->inverse_trans_unicode there.

thanks,
-- 
js
suse labs
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