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From: Dan Carpenter <dan.carpenter@oracle.com>
To: Greg KH <gregkh@linuxfoundation.org>
Cc: Christophe JAILLET <christophe.jaillet@wanadoo.fr>,
	jk@ozlabs.org, joel@jms.id.au, alistair@popple.id.au,
	eajames@linux.ibm.com, andrew@aj.id.au,
	linux-fsi@lists.ozlabs.org, linux-arm-kernel@lists.infradead.org,
	linux-aspeed@lists.ozlabs.org, linux-kernel@vger.kernel.org,
	kernel-janitors@vger.kernel.org
Subject: Re: [PATCH] fsi: Aspeed: Fix a potential double free
Date: Thu, 6 Jan 2022 11:14:19 +0300	[thread overview]
Message-ID: <20220106081418.GH7674@kadam> (raw)
In-Reply-To: <YcldM9sgYdjMYMtH@kroah.com>

On Mon, Dec 27, 2021 at 07:29:07AM +0100, Greg KH wrote:
> On Sun, Dec 26, 2021 at 05:56:02PM +0100, Christophe JAILLET wrote:
> > 'aspeed' is a devm_alloc'ed, so there is no need to free it explicitly or
> > there will be a double free().
> 
> A struct device can never be devm_alloced for obvious reasons.  Perhaps
> that is the real problem here?
> 

I don't understand how "aspeed" is a struct device.

I've been working on understanding device managed memory recently for
Smatch.  It's really complicated.  There are a bunch of rules/heuristics
that I'm slowly creating to generate new warnings but I'm a long way
from understanding it well myself.

regards,
dan carpenter


WARNING: multiple messages have this Message-ID (diff)
From: Dan Carpenter <dan.carpenter@oracle.com>
To: Greg KH <gregkh@linuxfoundation.org>
Cc: Christophe JAILLET <christophe.jaillet@wanadoo.fr>,
	jk@ozlabs.org, joel@jms.id.au, alistair@popple.id.au,
	eajames@linux.ibm.com, andrew@aj.id.au,
	linux-fsi@lists.ozlabs.org, linux-arm-kernel@lists.infradead.org,
	linux-aspeed@lists.ozlabs.org, linux-kernel@vger.kernel.org,
	kernel-janitors@vger.kernel.org
Subject: Re: [PATCH] fsi: Aspeed: Fix a potential double free
Date: Thu, 6 Jan 2022 11:14:19 +0300	[thread overview]
Message-ID: <20220106081418.GH7674@kadam> (raw)
In-Reply-To: <YcldM9sgYdjMYMtH@kroah.com>

On Mon, Dec 27, 2021 at 07:29:07AM +0100, Greg KH wrote:
> On Sun, Dec 26, 2021 at 05:56:02PM +0100, Christophe JAILLET wrote:
> > 'aspeed' is a devm_alloc'ed, so there is no need to free it explicitly or
> > there will be a double free().
> 
> A struct device can never be devm_alloced for obvious reasons.  Perhaps
> that is the real problem here?
> 

I don't understand how "aspeed" is a struct device.

I've been working on understanding device managed memory recently for
Smatch.  It's really complicated.  There are a bunch of rules/heuristics
that I'm slowly creating to generate new warnings but I'm a long way
from understanding it well myself.

regards,
dan carpenter


_______________________________________________
linux-arm-kernel mailing list
linux-arm-kernel@lists.infradead.org
http://lists.infradead.org/mailman/listinfo/linux-arm-kernel

  parent reply	other threads:[~2022-01-06  8:15 UTC|newest]

Thread overview: 14+ messages / expand[flat|nested]  mbox.gz  Atom feed  top
2021-12-26 16:56 [PATCH] fsi: Aspeed: Fix a potential double free Christophe JAILLET
2021-12-26 16:56 ` Christophe JAILLET
2021-12-27  6:29 ` Greg KH
2021-12-27  6:29   ` Greg KH
2021-12-27  7:48   ` Christophe JAILLET
2021-12-27  7:48     ` Christophe JAILLET
2022-01-06  8:14   ` Dan Carpenter [this message]
2022-01-06  8:14     ` Dan Carpenter
2022-01-06 17:25     ` Guenter Roeck
2022-01-06 17:25       ` Guenter Roeck
2022-01-06 18:35       ` Christophe JAILLET
2022-01-06 18:35         ` Christophe JAILLET
2022-01-07  1:35         ` Guenter Roeck
2022-01-07  1:35           ` Guenter Roeck

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