From: Michal Hocko <mhocko@kernel.org>
To: Alastair D'Silva <alastair@au1.ibm.com>
Cc: David Hildenbrand <david@redhat.com>,
alastair@d-silva.org, linux-kernel@vger.kernel.org,
Mike Rapoport <rppt@linux.vnet.ibm.com>,
Paul Mackerras <paulus@samba.org>,
"Aneesh Kumar K.V" <aneesh.kumar@linux.ibm.com>,
Andrew Morton <akpm@linux-foundation.org>,
linuxppc-dev@lists.ozlabs.org
Subject: Re: [PATCH] powerpc: Perform a bounds check in arch_add_memory
Date: Tue, 27 Aug 2019 08:28:44 +0200 [thread overview]
Message-ID: <20190827062844.GQ7538@dhcp22.suse.cz> (raw)
In-Reply-To: <20190827052047.31547-1-alastair@au1.ibm.com>
On Tue 27-08-19 15:20:46, Alastair D'Silva wrote:
> From: Alastair D'Silva <alastair@d-silva.org>
>
> It is possible for firmware to allocate memory ranges outside
> the range of physical memory that we support (MAX_PHYSMEM_BITS).
Doesn't that count as a FW bug? Do you have any evidence of that in the
field? Just wondering...
> This patch adds a bounds check to ensure that any hotplugged
> memory is addressable.
>
> Signed-off-by: Alastair D'Silva <alastair@d-silva.org>
> ---
> arch/powerpc/mm/mem.c | 3 +++
> 1 file changed, 3 insertions(+)
>
> diff --git a/arch/powerpc/mm/mem.c b/arch/powerpc/mm/mem.c
> index 9191a66b3bc5..de18fb73de30 100644
> --- a/arch/powerpc/mm/mem.c
> +++ b/arch/powerpc/mm/mem.c
> @@ -111,6 +111,9 @@ int __ref arch_add_memory(int nid, u64 start, u64 size,
> unsigned long nr_pages = size >> PAGE_SHIFT;
> int rc;
>
> + if ((start + size - 1) >> MAX_PHYSMEM_BITS)
> + return -EINVAL;
> +
> resize_hpt_for_hotplug(memblock_phys_mem_size());
>
> start = (unsigned long)__va(start);
> --
> 2.21.0
--
Michal Hocko
SUSE Labs
next prev parent reply other threads:[~2019-08-27 6:33 UTC|newest]
Thread overview: 9+ messages / expand[flat|nested] mbox.gz Atom feed top
2019-08-27 5:20 [PATCH] powerpc: Perform a bounds check in arch_add_memory Alastair D'Silva
2019-08-27 6:28 ` Michal Hocko [this message]
2019-08-27 6:39 ` Alastair D'Silva
2019-08-27 7:13 ` David Hildenbrand
2019-09-01 23:54 ` Alastair D'Silva
2019-09-02 7:28 ` David Hildenbrand
2019-09-04 5:25 ` Alastair D'Silva
2019-09-05 7:52 ` David Hildenbrand
2019-08-27 7:18 ` Michal Hocko
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