linux-kernel - Re: [PATCH v2 06/21] memblock: memblock_phys_alloc_try

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: <20190125193252.GH31519@rapoport-lnx>
Date:   Fri, 25 Jan 2019 21:32:52 +0200
From:   Mike Rapoport <rppt@...ux.ibm.com>
To:     Catalin Marinas <catalin.marinas@....com>
Cc:     linux-mm@...ck.org, Andrew Morton <akpm@...ux-foundation.org>,
        Christoph Hellwig <hch@....de>,
        "David S. Miller" <davem@...emloft.net>,
        Dennis Zhou <dennis@...nel.org>,
        Geert Uytterhoeven <geert@...ux-m68k.org>,
        Greentime Hu <green.hu@...il.com>,
        Greg Kroah-Hartman <gregkh@...uxfoundation.org>,
        Guan Xuetao <gxt@....edu.cn>, Guo Ren <guoren@...nel.org>,
        Heiko Carstens <heiko.carstens@...ibm.com>,
        Mark Salter <msalter@...hat.com>,
        Matt Turner <mattst88@...il.com>,
        Max Filippov <jcmvbkbc@...il.com>,
        Michael Ellerman <mpe@...erman.id.au>,
        Michal Simek <monstr@...str.eu>,
        Paul Burton <paul.burton@...s.com>,
        Petr Mladek <pmladek@...e.com>, Rich Felker <dalias@...c.org>,
        Richard Weinberger <richard@....at>,
        Rob Herring <robh+dt@...nel.org>,
        Russell King <linux@...linux.org.uk>,
        Stafford Horne <shorne@...il.com>,
        Tony Luck <tony.luck@...el.com>,
        Vineet Gupta <vgupta@...opsys.com>,
        Yoshinori Sato <ysato@...rs.sourceforge.jp>,
        devicetree@...r.kernel.org, kasan-dev@...glegroups.com,
        linux-alpha@...r.kernel.org, linux-arm-kernel@...ts.infradead.org,
        linux-c6x-dev@...ux-c6x.org, linux-ia64@...r.kernel.org,
        linux-kernel@...r.kernel.org, linux-m68k@...ts.linux-m68k.org,
        linux-mips@...r.kernel.org, linux-s390@...r.kernel.org,
        linux-sh@...r.kernel.org, linux-snps-arc@...ts.infradead.org,
        linux-um@...ts.infradead.org, linux-usb@...r.kernel.org,
        linux-xtensa@...ux-xtensa.org, linuxppc-dev@...ts.ozlabs.org,
        openrisc@...ts.librecores.org, sparclinux@...r.kernel.org,
        uclinux-h8-devel@...ts.sourceforge.jp, x86@...nel.org,
        xen-devel@...ts.xenproject.org
Subject: Re: [PATCH v2 06/21] memblock: memblock_phys_alloc_try_nid(): don't
 panic

On Fri, Jan 25, 2019 at 05:45:02PM +0000, Catalin Marinas wrote:
> On Mon, Jan 21, 2019 at 10:03:53AM +0200, Mike Rapoport wrote:
> > diff --git a/arch/arm64/mm/numa.c b/arch/arm64/mm/numa.c
> > index ae34e3a..2c61ea4 100644
> > --- a/arch/arm64/mm/numa.c
> > +++ b/arch/arm64/mm/numa.c
> > @@ -237,6 +237,10 @@ static void __init setup_node_data(int nid, u64 start_pfn, u64 end_pfn)
> >  		pr_info("Initmem setup node %d [<memory-less node>]\n", nid);
> >  
> >  	nd_pa = memblock_phys_alloc_try_nid(nd_size, SMP_CACHE_BYTES, nid);
> > +	if (!nd_pa)
> > +		panic("Cannot allocate %zu bytes for node %d data\n",
> > +		      nd_size, nid);
> > +
> >  	nd = __va(nd_pa);
> >  
> >  	/* report and initialize */
> 
> Does it mean that memblock_phys_alloc_try_nid() never returns valid
> physical memory starting at 0?

Yes, it does.
memblock_find_in_range_node() that is used by all allocation methods
skips the first page [1].
 
[1] https://git.kernel.org/pub/scm/linux/kernel/git/torvalds/linux.git/tree/mm/memblock.c#n257

> -- 
> Catalin
> 

-- 
Sincerely yours,
Mike.