Re: [PATCH v10 1/1] efi: a misc char interface for user to update efi firmware

From: Matt Fleming <matt@console-pimps.org>
To: "Bryan O'Donoghue" <pure.logic@nexus-software.ie>
Cc: "Kweh, Hock Leong" <hock.leong.kweh@intel.com>,
	Greg Kroah-Hartman <gregkh@linuxfoundation.org>,
	Ong Boon Leong <boon.leong.ong@intel.com>,
	LKML <linux-kernel@vger.kernel.org>,
	linux-efi@vger.kernel.org,
	Sam Protsenko <semen.protsenko@linaro.org>,
	Peter Jones <pjones@redhat.com>,
	Andy Lutomirski <luto@amacapital.net>,
	Roy Franz <roy.franz@linaro.org>, Borislav Petkov <bp@alien8.de>,
	James Bottomley <James.Bottomley@hansenpartnership.com>,
	Linux FS Devel <linux-fsdevel@vger.kernel.org>,
	Anvin H Peter <h.peter.anvin@intel.com>
Subject: Re: [PATCH v10 1/1] efi: a misc char interface for user to update efi firmware
Date: Thu, 21 Jan 2016 12:35:47 +0000	[thread overview]
Message-ID: <20160121123547.GC2510@codeblueprint.co.uk> (raw)
In-Reply-To: <1450717451.8767.69.camel@nexus-software.ie>

On Mon, 21 Dec, at 05:04:11PM, Bryan O'Donoghue wrote:
> > +static int efi_capsule_open(struct inode *inode, struct file *file)
> > +{
> > +	struct capsule_info *cap_info;
> > +
> > +	cap_info = kzalloc(sizeof(*cap_info), GFP_KERNEL);
> > +	if (!cap_info)
> > +		return -ENOMEM;
> > +
> > +	file->private_data = cap_info;
> > +
> > +	return 0;
> > +}
> 
> You have a memory leak here don't you ?
> 
> if I do 
> for (i = 0; i < N; i++) {
> 	fd = open(/dev/your_node);
> 	close(fd);
> }
> 
> You'll leak that kzalloc...

Nope, it gets freed in efi_capsule_release(). Though the code does
leak cap_info->pages if a capsule is successfully submitted to the
firmware.