linux-kernel - Re: [patch 9/9 v3] x86: export x86 boot

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Message-ID: <20131122024506.GB3874@dhcp-16-126.nay.redhat.com>
Date:	Fri, 22 Nov 2013 10:45:06 +0800
From:	Dave Young <dyoung@...hat.com>
To:	Greg KH <greg@...ah.com>
Cc:	linux-kernel@...r.kernel.org, linux-efi@...r.kernel.org,
	x86@...nel.org, mjg59@...f.ucam.org, hpa@...or.com,
	James.Bottomley@...senPartnership.com, vgoyal@...hat.com,
	ebiederm@...ssion.com, horms@...ge.net.au,
	kexec@...ts.infradead.org, bp@...en8.de, matt@...sole-pimps.org,
	toshi.kani@...com
Subject: Re: [patch 9/9 v3] x86: export x86 boot_params to sysfs

On 11/21/13 at 08:45am, Greg KH wrote:
> > +static struct kobj_attribute boot_params_version_attr =
> > +	__ATTR(version, S_IRUGO, boot_params_version_show, NULL);
> 
> __ATTR_RO() please.

Will do

> 
> > +static struct kobj_attribute type_attr =
> > +		__ATTR(type, S_IRUGO, setup_data_type_show, NULL);
> 
> __ATTR_RO() here too.

Will do

[snip]
> > +
> > +	ret = get_setup_data_size(nr, &size);
> > +	if (ret)
> > +		goto out_kobj;
> > +
> > +	data_attr.size = size;
> > +	ret = sysfs_create_bin_file(kobj, &data_attr);
> > +	if (ret)
> > +		goto out_file;
> > +	*kobjp = kobj;
> 
> You just raced with userspace (creating and announcing the kobject and
> then, afterward, at some later point in time, created the sysfs files.
> Please use the groups option to create the files properly before
> announcing the kobject to userspace.

Will do

[snip]
> > +		goto out_boot_params_kobj;
> > +	ret = sysfs_create_bin_file(boot_params_kobj,
> > +				      &boot_params_data_attr);
> > +	if (ret)
> > +		goto out_create_file;
> > +
> > +	ret = create_setup_data_nodes(boot_params_kobj);
> > +	if (ret)
> > +		goto out_create_bin;
> > +
> > +	return 0;
> 
> Same race condition here as well.  Use a groups structure please.
> 

Will use group attributes

Thanks for review
Dave
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