linux-kernel - Re: [PATCH 5.10 086/103] regmap: debugfs: Fix a memory leak when calling regmap_attach

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Message-ID: <20210115202639.GB8375@amd>
Date:   Fri, 15 Jan 2021 21:26:40 +0100
From:   Pavel Machek <pavel@....cz>
To:     Greg Kroah-Hartman <gregkh@...uxfoundation.org>
Cc:     linux-kernel@...r.kernel.org, stable@...r.kernel.org,
        Xiaolei Wang <xiaolei.wang@...driver.com>,
        Mark Brown <broonie@...nel.org>
Subject: Re: [PATCH 5.10 086/103] regmap: debugfs: Fix a memory leak when
 calling regmap_attach_dev

Hi!

> > From: Xiaolei Wang <xiaolei.wang@...driver.com>
> > 
> > commit cffa4b2122f5f3e53cf3d529bbc74651f95856d5 upstream.
> > 
> > After initializing the regmap through
> > syscon_regmap_lookup_by_compatible, then regmap_attach_dev to the
> > device, because the debugfs_name has been allocated, there is no
> > need to redistribute it again
> 
> ? redistribute?
> 
> Anyway, this patch is clearly buggy:
> 
> >  
> >  	if (!strcmp(name, "dummy")) {
> > -		kfree(map->debugfs_name);
> > +		if (!map->debugfs_name)
> > +			kfree(map->debugfs_name);
> >  
> 
> It runs kfree only if the variable is NULL. That's clearly useless,
> kfree(NULL) is NOP, and this causes memory leak.

103/ of the series fixes this up. Sorry for the noise... 

Best regards,
								Pavel
-- 
http://www.livejournal.com/~pavelmachek

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