Re: [PATCH] staging: dgnc: fix compile warning frame size is larger than 1024 bytes

[Martin Kepplinger]

Am 2014-05-06 15:33, schrieb Dan Carpenter:
> On Tue, May 06, 2014 at 02:41:37PM +0200, Martin Kepplinger wrote:
>> fix following warning by dynamically allocating memory:
>> dgnc_tty.c:583:1: warning: the frame size of 1060 bytes is larger than 1024 bytes [-Wframe-larger-than=]
>>
>> Signed-off-by: Martin Kepplinger <martink@xxxxxxxxx>
>> ---
>> This is more of a question. Is this a desired solution to fixing such a
>> frame size warning?
> 
> This warning is because the kernel uses an 8k stack so you add up all
> the stack memory used by each function from the syscall to here.  If
> it adds up to more than 8k then it's a bug.  The 1k limit per function
> is just a hack to spot where people are maybe being reckless.

nice. thanks.

> 
> There are no kfree()s and this function is called with a spin_lock held
> so this patch introduces a couple bugs.

I know, it should have been just a question (probably to kernelnewbies'
list). Sorry for the noise.

> 
> There may be a better way to allocate this.  Like maybe at probe() and
> then use spinlocks to serialize access to the buffer.  But sometimes
> that's a very bad idea.
> 
> It's better if you know the driver a bit and can test things.
> 
> regards,
> dan carpenter
> 
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