linux-kernel - Re: [Bug fix PATCH v4] Reusing a resource structure allocated by bootmem

lists.openwall.net		lists / announce owl-users owl-dev john-users john-dev passwdqc-users yescrypt popa3d-users / oss-security kernel-hardening musl sabotage tlsify passwords / crypt-dev xvendor / Bugtraq Full-Disclosure linux-kernel linux-netdev linux-ext4 linux-hardening linux-cve-announce PHC
Open Source and information security mailing list archives

Hash Suite: Windows password security audit tool. GUI, reports in PDF.

[<prev] [next>] [<thread-prev] [thread-next>] [day] [month] [year] [list]

Message-ID: <1366327735.3824.50.camel@misato.fc.hp.com>
Date:	Thu, 18 Apr 2013 17:28:55 -0600
From:	Toshi Kani <toshi.kani@...com>
To:	Yasuaki Ishimatsu <isimatu.yasuaki@...fujitsu.com>
Cc:	akpm@...ux-foundation.org, linuxram@...ibm.com,
	rientjes@...gle.com, linux-kernel@...r.kernel.org,
	linux-mm@...ck.org
Subject: Re: [Bug fix PATCH v4] Reusing a resource structure allocated by
 bootmem

On Fri, 2013-04-19 at 08:33 +0900, Yasuaki Ishimatsu wrote:
 :
> >
> >> +static struct resource *get_resource(gfp_t flags)
> >> +{
> >> +	struct resource *res = NULL;
> >> +
> >> +	spin_lock(&bootmem_resource_lock);
> >> +	if (bootmem_resource.sibling) {
> >> +		res = bootmem_resource.sibling;
> >> +		bootmem_resource.sibling = res->sibling;
> >> +		memset(res, 0, sizeof(struct resource));
> >> +	}
> >> +	spin_unlock(&bootmem_resource_lock);
> >
> 
> > I prefer to keep memset() outside of the spin lock.
> >
> > spin_lock(&bootmem_resource_lock);
> > if (..) {
> > 	:
> > 	spin_unlock(&bootmem_resource_lock);
> > 	memset(res, 0, sizeof(struct resource));
> > } else {
> > 	spin_unlock(&bootmem_resource_lock);
> > 	res = kzalloc(sizeof(struct resource), flags);
> > }
> 
> Hmm. It is a little ugly. How about it?
> 
> spin_lock(&bootmem_resource_lock);
> if (bootmem_resource.sibling) {
> 	res = bootmem_resource.sibling;
> 	bootmem_resource.sibling = res->sibling;
> }
> spin_unlock(&bootmem_resource_lock);
> 
> if (res)
> 	memset(res, 0, sizeof(struct resource));
> else	
> 	res = kzalloc(sizeof(struct resource), flags);

Sounds good to me.

Thanks,
-Toshi


--
To unsubscribe from this list: send the line "unsubscribe linux-kernel" in
the body of a message to majordomo@...r.kernel.org
More majordomo info at  http://vger.kernel.org/majordomo-info.html
Please read the FAQ at  http://www.tux.org/lkml/