From: Geunsik Lim <geunsik.lim@gmail.com>
To: Andrew Morton <akpm@linux-foundation.org>
Cc: "H. Peter Anvin" <hpa@linux.intel.com>,
Yinghai Lu <yinghai@kernel.org>,
linux-kernel <linux-kernel@vger.kernel.org>,
linux-mm <linux-mm@kvack.org>
Subject: Re: [PATCH] Fix potentially derefencing uninitialized 'r'.
Date: Mon, 20 Feb 2012 16:57:35 +0900 [thread overview]
Message-ID: <CAGFP0LJhqC9xqn=BmoOyRL_wJX8=KU=Z4+k=t=C3MLhWYqWLnQ@mail.gmail.com> (raw)
In-Reply-To: <20120217142806.07a97347.akpm@linux-foundation.org>
On Sat, Feb 18, 2012 at 7:28 AM, Andrew Morton
<akpm@linux-foundation.org> wrote:
> On Fri, 3 Feb 2012 17:20:56 +0900
> Geunsik Lim <geunsik.lim@gmail.com> wrote:
>
>> struct memblock_region 'r' will not be initialized potentially
>> because of while statement's condition in __next_mem_pfn_range()function.
>> Initialize struct memblock_region data structure by default.
>>
>> Signed-off-by: Geunsik Lim <geunsik.lim@samsung.com>
>> ---
>> mm/memblock.c | 2 +-
>> 1 files changed, 1 insertions(+), 1 deletions(-)
>>
>> diff --git a/mm/memblock.c b/mm/memblock.c
>> index 77b5f22..867f5a2 100644
>> --- a/mm/memblock.c
>> +++ b/mm/memblock.c
>> @@ -671,7 +671,7 @@ void __init_memblock __next_mem_pfn_range(int *idx, int nid,
>> unsigned long *out_end_pfn, int *out_nid)
>> {
>> struct memblock_type *type = &memblock.memory;
>> - struct memblock_region *r;
>> + struct memblock_region *r = &type->regions[*idx];
>>
>> while (++*idx < type->cnt) {
>> r = &type->regions[*idx];
>
> The following `if' test prevents any such dereference.
>
> Maybe you saw a compilation warning (I didn't). If so,
> unintialized_var() is one way of suppressing it.
Yepp. This patch is for solving compilation warning as you commented.
>
> A better way is to reorganise the code (nicely). Often that option
> isn't available.
I will post patch again after reorganizing the code with better way.
Thanks.
>
>
--
----
Best regards,
Geunsik Lim, Samsung Electronics
http://leemgs.fedorapeople.org
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prev parent reply other threads:[~2012-02-20 7:57 UTC|newest]
Thread overview: 3+ messages / expand[flat|nested] mbox.gz Atom feed top
2012-02-03 8:20 Geunsik Lim
2012-02-17 22:28 ` Andrew Morton
2012-02-20 7:57 ` Geunsik Lim [this message]
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