linux-hardening - Re: [RFC PATCH v2 11/19] mm/sparsemem: Use alloc

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: <f77f3312a1b17b8f8de2ccf0f40f9f19f4a9f151.camel@intel.com>
Date:   Tue, 31 Aug 2021 18:25:23 +0000
From:   "Edgecombe, Rick P" <rick.p.edgecombe@...el.com>
To:     "rppt@...nel.org" <rppt@...nel.org>
CC:     "linux-kernel@...r.kernel.org" <linux-kernel@...r.kernel.org>,
        "peterz@...radead.org" <peterz@...radead.org>,
        "keescook@...omium.org" <keescook@...omium.org>,
        "Weiny, Ira" <ira.weiny@...el.com>,
        "linux-hardening@...r.kernel.org" <linux-hardening@...r.kernel.org>,
        "linux-mm@...ck.org" <linux-mm@...ck.org>,
        "vbabka@...e.cz" <vbabka@...e.cz>,
        "x86@...nel.org" <x86@...nel.org>,
        "akpm@...ux-foundation.org" <akpm@...ux-foundation.org>,
        "Williams, Dan J" <dan.j.williams@...el.com>,
        "Lutomirski, Andy" <luto@...nel.org>,
        "kernel-hardening@...ts.openwall.com" 
        <kernel-hardening@...ts.openwall.com>,
        "Hansen, Dave" <dave.hansen@...el.com>,
        "shakeelb@...gle.com" <shakeelb@...gle.com>
Subject: Re: [RFC PATCH v2 11/19] mm/sparsemem: Use alloc_table() for table
 allocations

On Tue, 2021-08-31 at 11:55 +0300, Mike Rapoport wrote:
> On Mon, Aug 30, 2021 at 04:59:19PM -0700, Rick Edgecombe wrote:
<trim> 
> > -static void * __meminit vmemmap_alloc_block_zero(unsigned long
> > size, int node)
> > +static void * __meminit vmemmap_alloc_table(int node)
> >  {
> > -	void *p = vmemmap_alloc_block(size, node);
> > +	void *p;
> > +	if (slab_is_available()) {
> > +		struct page *page = alloc_table_node(GFP_KERNEL |
> > __GFP_ZERO, node);
> 
> This change removes __GFP_RETRY_MAYFAIL|__GFP_NOWARN from the
> original gfp
> vmemmap_alloc_block() used.
Oh, yea good point. Hmm, I guess grouped pages could be aware of that
flag too. Would be a small addition, but it starts to grow
unfortunately.

> Not sure __GFP_RETRY_MAYFAIL is really needed in
> vmemmap_alloc_block_zero()
> at the first place, though.
Looks like due to a real issue:
055e4fd96e95b0eee0d92fd54a26be7f0d3bcad0

I think it should not affect PKS tables for now, so maybe I can make
separate logic instead. I'll look into it. Thanks.
> 
> More broadly, maybe it makes sense to split boot time and memory
> hotplug
> paths and use pxd_alloc() for the latter.
> 
> > +
> > +		if (!page)
> > +			return NULL;
> > +		return page_address(page);
> > +	}
> >  
> > +	p = __earlyonly_bootmem_alloc(node, PAGE_SIZE, PAGE_SIZE,
> > __pa(MAX_DMA_ADDRESS));
> 
> Opportunistically rename to __earlyonly_memblock_alloc()? ;-)
> 
Heh, I can. Just grepping, there are several other instances of
foo_bootmem() only calling foo_memblock() pattern scattered about. Or
maybe I'm missing the distinction.

<trim>