From: Sinan Kaya <okaya@codeaurora.org>
To: Laura Abbott <labbott@redhat.com>
Cc: Vinod Koul <vinod.koul@intel.com>,
Dan Williams <dan.j.williams@intel.com>,
dmaengine@vger.kernel.org, linux-kernel@vger.kernel.org,
kernel-hardening@lists.openwall.com,
Kees Cook <keescook@chromium.org>,
dmaengine-owner@vger.kernel.org
Subject: dmaengine: dmatest: Remove use of VLAs
Date: Mon, 09 Apr 2018 19:19:16 -0400 [thread overview]
Message-ID: <e2991519fb007653c35bf52210af36b9@codeaurora.org> (raw)
On 2018-04-09 19:14, Laura Abbott wrote:
> On 04/09/2018 03:48 PM, Sinan Kaya wrote:
>> On 4/9/2018 5:06 PM, Laura Abbott wrote:
>>> + /* dst_cnt can't be more than u8 */
>>> + dma_addr_t dma_pq[255];
>>
>> This is 2k stack space on 64 bit architectures. Isn't that a lot?
>>
>
> Depends on your definition of 'a lot'. My assumption was that
> since this was a test module there would be some willingness
> to be a bit more generous. The problem is the array size is
> based off of the parameters passed in, although oddly enough
> it's based off of the minimum of two variables. If you have
> a suggestion for a tighter bound we can use that. Another
> option is to just switch to allocating the array with kmalloc.
> That might be reasonable here since there's other setup
> that happens before the test starts.
I think allocation is a better choice.
>
> Thanks,
> Laura
>
> --
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WARNING: multiple messages have this Message-ID (diff)
From: okaya@codeaurora.org
To: Laura Abbott <labbott@redhat.com>
Cc: Vinod Koul <vinod.koul@intel.com>,
Dan Williams <dan.j.williams@intel.com>,
dmaengine@vger.kernel.org, linux-kernel@vger.kernel.org,
kernel-hardening@lists.openwall.com,
Kees Cook <keescook@chromium.org>,
dmaengine-owner@vger.kernel.org
Subject: Re: [PATCH] dmaengine: dmatest: Remove use of VLAs
Date: Mon, 09 Apr 2018 19:19:16 -0400 [thread overview]
Message-ID: <e2991519fb007653c35bf52210af36b9@codeaurora.org> (raw)
In-Reply-To: <9bdd8bb4-b6d9-e170-b585-b2dc3b8f0d67@redhat.com>
On 2018-04-09 19:14, Laura Abbott wrote:
> On 04/09/2018 03:48 PM, Sinan Kaya wrote:
>> On 4/9/2018 5:06 PM, Laura Abbott wrote:
>>> + /* dst_cnt can't be more than u8 */
>>> + dma_addr_t dma_pq[255];
>>
>> This is 2k stack space on 64 bit architectures. Isn't that a lot?
>>
>
> Depends on your definition of 'a lot'. My assumption was that
> since this was a test module there would be some willingness
> to be a bit more generous. The problem is the array size is
> based off of the parameters passed in, although oddly enough
> it's based off of the minimum of two variables. If you have
> a suggestion for a tighter bound we can use that. Another
> option is to just switch to allocating the array with kmalloc.
> That might be reasonable here since there's other setup
> that happens before the test starts.
I think allocation is a better choice.
>
> Thanks,
> Laura
>
> --
> To unsubscribe from this list: send the line "unsubscribe dmaengine" in
> the body of a message to majordomo@vger.kernel.org
> More majordomo info at http://vger.kernel.org/majordomo-info.html
next reply other threads:[~2018-04-09 23:19 UTC|newest]
Thread overview: 13+ messages / expand[flat|nested] mbox.gz Atom feed top
2018-04-09 23:19 Sinan Kaya [this message]
2018-04-09 23:19 ` [PATCH] dmaengine: dmatest: Remove use of VLAs okaya
-- strict thread matches above, loose matches on Subject: below --
2018-04-10 15:38 Vinod Koul
2018-04-10 15:38 ` [PATCH] " Vinod Koul
2018-04-10 4:00 kbuild test robot
2018-04-10 4:00 ` [PATCH] " kbuild test robot
2018-04-10 4:00 ` kbuild test robot
2018-04-09 23:14 Laura Abbott
2018-04-09 23:14 ` [PATCH] " Laura Abbott
2018-04-09 22:48 Sinan Kaya
2018-04-09 22:48 ` [PATCH] " Sinan Kaya
2018-04-09 21:06 Laura Abbott
2018-04-09 21:06 ` [PATCH] " Laura Abbott
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