From: Anshuman Khandual <khandual@linux.vnet.ibm.com>
To: Michal Hocko <mhocko@kernel.org>,
Anshuman Khandual <khandual@linux.vnet.ibm.com>
Cc: linux-kernel@vger.kernel.org, linux-mm@kvack.org, vbabka@suse.cz,
akpm@linux-foundation.org
Subject: Re: [RFC] nodemask: Consider MAX_NUMNODES inside node_isset
Date: Tue, 3 Jan 2017 14:37:09 +0530 [thread overview]
Message-ID: <6c7ecb18-2ad0-f38a-1dc8-3c6c405b87ce@linux.vnet.ibm.com> (raw)
In-Reply-To: <20170103084418.GC30111@dhcp22.suse.cz>
On 01/03/2017 02:14 PM, Michal Hocko wrote:
> On Tue 03-01-17 13:57:53, Anshuman Khandual wrote:
>> node_isset can give incorrect result if the node number is beyond the
>> bitmask size (MAX_NUMNODES in this case) which is not checked inside
>> test_bit. Hence check for the bit limits (MAX_NUMNODES) inside the
>> node_isset function before calling test_bit.
> Could you be more specific when such a thing might happen? Have you seen
> any in-kernel user who would give such a bogus node?
Have not seen this through any in-kernel use case. While rebasing the CDM
zonelist rebuilding series, I came across this through an error path when
a bogus node value of 256 (MAX_NUMNODES on POWER) is received when we call
first_node() on an empty nodemask (which itself seems weird as well).
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next prev parent reply other threads:[~2017-01-03 9:07 UTC|newest]
Thread overview: 5+ messages / expand[flat|nested] mbox.gz Atom feed top
2017-01-03 8:27 Anshuman Khandual
2017-01-03 8:44 ` Michal Hocko
2017-01-03 9:07 ` Anshuman Khandual [this message]
2017-01-03 9:17 ` Michal Hocko
2017-01-03 9:47 ` Anshuman Khandual
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