DEAR Guennadi,
Thanks for your reply.
SOC-Camera driver module is a great component based on V4L2.
It's very easy to use.I can write ISP driver and sensor driver separately for
our company's chip which is in reseach.I am looking forward to your best
resolution.
robin.li
------------------ 原始邮件 ------------------
发件人: "Guennadi Liakhovetski"<g.liakhovetski@xxxxxx>;
发送时间: 2012年11月9日(星期五) 晚上10:01
收件人: "再回首"<308123027@xxxxxx>;
抄送: "linux-media"<linux-media@xxxxxxxxxxxxxxx>;
主题: Re: 回复： soc camera driver module may case memory leak
Hi
Well, I must confess, I'm surprised:-) It looks like you're right. This
leak, if indeed there is one, has been there since the very first version
of soc-camera. I've spent some time looking at the code and so far I don't
find an explanation for the missing videobuf_mmap_free() call. I'll have
another look and, unless I find an explanation, why it's not needed, I'll
make a patch.
Also keep in mind, that this bug is only relevant for videobuf(1) drivers,
which anyway have to be converted to videobuf2;-)
Thanks
Guennadi
On Wed, 7 Nov 2012, ~F~M ~[~^ ~V wrote:
> Dear Guennadi
>
> I'm sure it's a bug.In linux-2.6.x, we call open() will allocate a struct soc_camera_file which contains struct videobuf_queue;then usr will call request_buffer, soc_camera module will call videobuf_alloc_vb(q) which will be installed in q->bufs[i].
> My question is how to free q->bufs[i] which is allocated from vb = kzalloc(size + sizeof(*mem), GFP_KERNEL) if we use videobuf-dma-contig memory model?
> videobuf_mmap_free()->kfree(q->bufs[i]) should call at every call close();we can't call kfree(q->bufs[i]) at q->ops->buf_release which is called in stream_off(), because q->bufs[i] reserve struct videobuf_mapping, unmap() will can't free videobuf which is used to store video data. Also can't call videobuf_mmap_free()->kfree(q->bufs[i]) at last close(), because in linux-2.6.x once open() allocates a videobuf_queue.
> In linux-3.x.x, we should call videobuf_mmap_free()->kfree(q->bufs[i]) only once at module remove callbcak function.
> You say, videobuf mmap allocations will be freed automatically. I want to known soc_camera module how to free q->bufs[i] automatically.
> If is there no bug in soc camera module , i'm sure all device driver use soc camera module have bugs, such as sh_mobile_ceu_caera.c, mx1_caera.c, mx3_caera.c etc. all of them donn't call videobuf_mmap_free()->kfree(q->bufs[i]).
>
> Your reply will be higly appreciated!
>
>
> ------------------ 原始邮件 ------------------
> 发件人: "Guennadi Liakhovetski"<g.liakhovetski@xxxxxx>;
> 发送时间: 2012年11月6日(星期二) 晚上7:30
> 收件人: "再回首"<308123027@xxxxxx>;
> 抄送: "linux-media"<linux-media@xxxxxxxxxxxxxxx>;
> 主题: Re: soc camera driver module may case memory leak
>
>
> Hi
>
> On Mon, 5 Nov 2012, ~F~M ~[~^ ~V wrote:
>
> > Dear sir:
> > why not call "videobuf_mmap_free",when device close call "soc_camera_close" in linux-2.6.x;
>
> I haven't found any version, where this has been done. I don't think this
> is needed, because videobuf mmap allocations will be freed automatically
> upon the last close(). Please, dismiss your bugzilla entry.
>
> Thanks
> Guennadi
>
> > do the same in linux-3.x.x?
> > video capture flow:
> > 1)open
> > 2)set fmt
> > 3)request buffer-->__videobuf_mmap_setup-->videobuf_alloc_vb(q)
> > 4)mmap
> > 5)enqueue, dequeue
> > 6)unmap
> > 7)close--->soc_camera_close-->?should call:videobuf_mmap_free
> > NOTE:
> > I have reviewed all the code, found:soc_camera_driver device driver coders has no way(callback function) to call videobuf_mmap_free; it will case memory leak.N r y b X ǧv ^ ){.n + { bj) w*jg ݢj/ z ޖ 2 ޙ & )ߡ a G h j:+v w ٥
>
> ---
> Guennadi Liakhovetski, Ph.D.
> Freelance Open-Source Software Developer
> http://www.open-technology.de/
---
Guennadi Liakhovetski, Ph.D.
Freelance Open-Source Software Developer
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