From: Yisheng Xie <xieyisheng1@huawei.com>
To: Alexander Potapenko <glider@google.com>
Cc: Andrew Morton <akpm@linux-foundation.org>,
Linux Memory Management List <linux-mm@kvack.org>,
Dmitriy Vyukov <dvyukov@google.com>,
Vlastimil Babka <vbabka@suse.cz>,
"mhocko@suse.com" <mhocko@suse.com>,
"Linux Kernel Mailing List" <linux-kernel@vger.kernel.org>
Subject: Re: [PATCH] mm/mempolicy: Avoid use uninitialized preferred_node
Date: Fri, 9 Mar 2018 19:10:43 +0800 [thread overview]
Message-ID: <a4efd431-39c3-8ede-9fa1-e69924263ce0@huawei.com> (raw)
In-Reply-To: <CAG_fn=XP6X5rqRVBameyU-F2UOc4hpbowUBNxZENf2ZHpMSmfQ@mail.gmail.com>
Hi Alexander ,
On 2018/3/9 18:49, Alexander Potapenko wrote:
> On Fri, Mar 9, 2018 at 6:21 AM, Yisheng Xie <xieyisheng1@huawei.com> wrote:
>> Alexander reported an use of uninitialized memory in __mpol_equal(),
>> which is caused by incorrect use of preferred_node.
>>
>> When mempolicy in mode MPOL_PREFERRED with flags MPOL_F_LOCAL, it use
>> numa_node_id() instead of preferred_node, however, __mpol_equeue() use
>> preferred_node without check whether it is MPOL_F_LOCAL or not.
>>
>> Reported-by: Alexander Potapenko <glider@google.com>
>> Signed-off-by: Yisheng Xie <xieyisheng1@huawei.com>
> Tested-by: Alexander Potapenko <glider@google.com>
Thanks,
>
> I confirm that the patch fixes the problem. Thanks for the quick turnaround!
> Any idea which commit had introduced the bug in the first place?
IIUC, It is introduce by:
Fixes: fc36b8d3d819 (mempolicy: use MPOL_F_LOCAL to Indicate Preferred Local Policy)
Thanks
Yisheng
>> ---
>> mm/mempolicy.c | 3 +++
>> 1 file changed, 3 insertions(+)
>>
>> diff --git a/mm/mempolicy.c b/mm/mempolicy.c
>> index d879f1d..641545e 100644
>> --- a/mm/mempolicy.c
>> +++ b/mm/mempolicy.c
>> @@ -2124,6 +2124,9 @@ bool __mpol_equal(struct mempolicy *a, struct mempolicy *b)
>> case MPOL_INTERLEAVE:
>> return !!nodes_equal(a->v.nodes, b->v.nodes);
>> case MPOL_PREFERRED:
>> + /* a's flags is the same as b's */
>> + if (a->flags & MPOL_F_LOCAL)
>> + return true;
>> return a->v.preferred_node == b->v.preferred_node;
>> default:
>> BUG();
>> --
>> 1.8.3.1
>>
>
>
>
prev parent reply other threads:[~2018-03-09 11:10 UTC|newest]
Thread overview: 3+ messages / expand[flat|nested] mbox.gz Atom feed top
[not found] <CAG_fn=VW5tfzT6cHJd+jF=t3WO6XS3HqSF_TYnKdycX_M_48vw@mail.gmail.com>
2018-03-09 5:21 ` [PATCH] mm/mempolicy: Avoid use uninitialized preferred_node Yisheng Xie
2018-03-09 10:49 ` Alexander Potapenko
2018-03-09 11:10 ` Yisheng Xie [this message]
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