drivers/dma/xilinx/xilinx_dpdma.c:1172 xilinx_dpdma_synchronize() error: double unlocked 'chan->vchan.lock' (orig line 1170)

drivers/dma/xilinx/xilinx_dpdma.c:1172 xilinx_dpdma_synchronize() error: double unlocked 'chan->vchan.lock' (orig line 1170)

[kernel test robot]

[-- Attachment #1: Type: text/plain, Size: 2090 bytes --]

tree:   https://git.kernel.org/pub/scm/linux/kernel/git/torvalds/linux.git master
head:   c636eef2ee3696f261a35f34989842701a107895
commit: 7cbb0c63de3fc218fd06ecfedb477772a4d12f76 dmaengine: xilinx: dpdma: Add the Xilinx DisplayPort DMA engine driver
date:   4 weeks ago
config: h8300-randconfig-m031-20200811 (attached as .config)
compiler: h8300-linux-gcc (GCC) 9.3.0

If you fix the issue, kindly add following tag as appropriate
Reported-by: kernel test robot <lkp@intel.com>

smatch warnings:
drivers/dma/xilinx/xilinx_dpdma.c:1172 xilinx_dpdma_synchronize() error: double unlocked 'chan->vchan.lock' (orig line 1170)

vim +1172 drivers/dma/xilinx/xilinx_dpdma.c

  1140	
  1141	/**
  1142	 * xilinx_dpdma_synchronize - Synchronize callback execution
  1143	 * @dchan: DMA channel
  1144	 *
  1145	 * Synchronizing callback execution ensures that all previously issued
  1146	 * transfers have completed and all associated callbacks have been called and
  1147	 * have returned.
  1148	 *
  1149	 * This function waits for the DMA channel to stop. It assumes it has been
  1150	 * paused by a previous call to dmaengine_terminate_async(), and that no new
  1151	 * pending descriptors have been issued with dma_async_issue_pending(). The
  1152	 * behaviour is undefined otherwise.
  1153	 */
  1154	static void xilinx_dpdma_synchronize(struct dma_chan *dchan)
  1155	{
  1156		struct xilinx_dpdma_chan *chan = to_xilinx_chan(dchan);
  1157		unsigned long flags;
  1158	
  1159		xilinx_dpdma_chan_stop(chan);
  1160	
  1161		spin_lock_irqsave(&chan->vchan.lock, flags);
  1162		if (chan->desc.pending) {
  1163			vchan_terminate_vdesc(&chan->desc.pending->vdesc);
  1164			chan->desc.pending = NULL;
  1165		}
  1166		if (chan->desc.active) {
  1167			vchan_terminate_vdesc(&chan->desc.active->vdesc);
  1168			chan->desc.active = NULL;
  1169		}
> 1170		spin_unlock_irqrestore(&chan->vchan.lock, flags);
  1171	
> 1172		vchan_synchronize(&chan->vchan);
  1173	}
  1174	

---
0-DAY CI Kernel Test Service, Intel Corporation
https://lists.01.org/hyperkitty/list/kbuild-all@lists.01.org

[-- Attachment #2: .config.gz --]
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Re: drivers/dma/xilinx/xilinx_dpdma.c:1172 xilinx_dpdma_synchronize() error: double unlocked 'chan->vchan.lock' (orig line 1170)

[Laurent Pinchart]

On Wed, Aug 12, 2020 at 06:37:59AM +0800, kernel test robot wrote:
> tree:   https://git.kernel.org/pub/scm/linux/kernel/git/torvalds/linux.git master
> head:   c636eef2ee3696f261a35f34989842701a107895
> commit: 7cbb0c63de3fc218fd06ecfedb477772a4d12f76 dmaengine: xilinx: dpdma: Add the Xilinx DisplayPort DMA engine driver
> date:   4 weeks ago
> config: h8300-randconfig-m031-20200811 (attached as .config)
> compiler: h8300-linux-gcc (GCC) 9.3.0
> 
> If you fix the issue, kindly add following tag as appropriate
> Reported-by: kernel test robot <lkp@intel.com>
> 
> smatch warnings:
> drivers/dma/xilinx/xilinx_dpdma.c:1172 xilinx_dpdma_synchronize() error: double unlocked 'chan->vchan.lock' (orig line 1170)

Unless I'm mistaken, this is a false positive. I'd appreciate if someone
could check if I'm missing something obvious.

> vim +1172 drivers/dma/xilinx/xilinx_dpdma.c
> 
>   1140	
>   1141	/**
>   1142	 * xilinx_dpdma_synchronize - Synchronize callback execution
>   1143	 * @dchan: DMA channel
>   1144	 *
>   1145	 * Synchronizing callback execution ensures that all previously issued
>   1146	 * transfers have completed and all associated callbacks have been called and
>   1147	 * have returned.
>   1148	 *
>   1149	 * This function waits for the DMA channel to stop. It assumes it has been
>   1150	 * paused by a previous call to dmaengine_terminate_async(), and that no new
>   1151	 * pending descriptors have been issued with dma_async_issue_pending(). The
>   1152	 * behaviour is undefined otherwise.
>   1153	 */
>   1154	static void xilinx_dpdma_synchronize(struct dma_chan *dchan)
>   1155	{
>   1156		struct xilinx_dpdma_chan *chan = to_xilinx_chan(dchan);
>   1157		unsigned long flags;
>   1158	
>   1159		xilinx_dpdma_chan_stop(chan);
>   1160	
>   1161		spin_lock_irqsave(&chan->vchan.lock, flags);
>   1162		if (chan->desc.pending) {
>   1163			vchan_terminate_vdesc(&chan->desc.pending->vdesc);
>   1164			chan->desc.pending = NULL;
>   1165		}
>   1166		if (chan->desc.active) {
>   1167			vchan_terminate_vdesc(&chan->desc.active->vdesc);
>   1168			chan->desc.active = NULL;
>   1169		}
> > 1170		spin_unlock_irqrestore(&chan->vchan.lock, flags);
>   1171	
> > 1172		vchan_synchronize(&chan->vchan);
>   1173	}
>   1174	
> 

-- 
Regards,

Laurent Pinchart

Re: drivers/dma/xilinx/xilinx_dpdma.c:1172 xilinx_dpdma_synchronize() error: double unlocked 'chan->vchan.lock' (orig line 1170)

[Vinod Koul]

HI Laurent,

On 12-08-20, 01:50, Laurent Pinchart wrote:
> On Wed, Aug 12, 2020 at 06:37:59AM +0800, kernel test robot wrote:
> > tree:   https://git.kernel.org/pub/scm/linux/kernel/git/torvalds/linux.git master
> > head:   c636eef2ee3696f261a35f34989842701a107895
> > commit: 7cbb0c63de3fc218fd06ecfedb477772a4d12f76 dmaengine: xilinx: dpdma: Add the Xilinx DisplayPort DMA engine driver
> > date:   4 weeks ago
> > config: h8300-randconfig-m031-20200811 (attached as .config)
> > compiler: h8300-linux-gcc (GCC) 9.3.0
> > 
> > If you fix the issue, kindly add following tag as appropriate
> > Reported-by: kernel test robot <lkp@intel.com>
> > 
> > smatch warnings:
> > drivers/dma/xilinx/xilinx_dpdma.c:1172 xilinx_dpdma_synchronize() error: double unlocked 'chan->vchan.lock' (orig line 1170)
> 
> Unless I'm mistaken, this is a false positive. I'd appreciate if someone
> could check if I'm missing something obvious.
> 
> > vim +1172 drivers/dma/xilinx/xilinx_dpdma.c
> > 
> >   1140	
> >   1141	/**
> >   1142	 * xilinx_dpdma_synchronize - Synchronize callback execution
> >   1143	 * @dchan: DMA channel
> >   1144	 *
> >   1145	 * Synchronizing callback execution ensures that all previously issued
> >   1146	 * transfers have completed and all associated callbacks have been called and
> >   1147	 * have returned.
> >   1148	 *
> >   1149	 * This function waits for the DMA channel to stop. It assumes it has been
> >   1150	 * paused by a previous call to dmaengine_terminate_async(), and that no new
> >   1151	 * pending descriptors have been issued with dma_async_issue_pending(). The
> >   1152	 * behaviour is undefined otherwise.
> >   1153	 */
> >   1154	static void xilinx_dpdma_synchronize(struct dma_chan *dchan)
> >   1155	{
> >   1156		struct xilinx_dpdma_chan *chan = to_xilinx_chan(dchan);
> >   1157		unsigned long flags;
> >   1158	
> >   1159		xilinx_dpdma_chan_stop(chan);
> >   1160	
> >   1161		spin_lock_irqsave(&chan->vchan.lock, flags);

Lock is held here

> >   1162		if (chan->desc.pending) {
> >   1163			vchan_terminate_vdesc(&chan->desc.pending->vdesc);

This should be called with lock held

> >   1164			chan->desc.pending = NULL;
> >   1165		}
> >   1166		if (chan->desc.active) {
> >   1167			vchan_terminate_vdesc(&chan->desc.active->vdesc);

same here

> >   1168			chan->desc.active = NULL;
> >   1169		}
> > > 1170		spin_unlock_irqrestore(&chan->vchan.lock, flags);

Dropped

> >   1171	
> > > 1172		vchan_synchronize(&chan->vchan);

This should be called without lock

So I agree with you, looks like a false positive to me as well

-- 
~Vinod

RE: [kbuild-all] Re: drivers/dma/xilinx/xilinx_dpdma.c:1172 xilinx_dpdma_synchronize() error: double unlocked 'chan->vchan.lock' (orig line 1170)

[Xia, Hui]

>-----Original Message-----
>From: Laurent Pinchart <laurent.pinchart@ideasonboard.com>
>Sent: 2020年8月12日 6:50
>To: kernel test robot <lkp@intel.com>
>Cc: Hyun Kwon <hyun.kwon@xilinx.com>; kbuild-all@lists.01.org; linux-
>kernel@vger.kernel.org; Vinod Koul <vkoul@kernel.org>; Tejas Upadhyay
><tejasu@xilinx.com>; Michal Simek <monstr@monstr.eu>
>Subject: [kbuild-all] Re: drivers/dma/xilinx/xilinx_dpdma.c:1172
>xilinx_dpdma_synchronize() error: double unlocked 'chan->vchan.lock' (orig line
>1170)
>
>On Wed, Aug 12, 2020 at 06:37:59AM +0800, kernel test robot wrote:
>> tree:   https://git.kernel.org/pub/scm/linux/kernel/git/torvalds/linux.git master
>> head:   c636eef2ee3696f261a35f34989842701a107895
>> commit: 7cbb0c63de3fc218fd06ecfedb477772a4d12f76 dmaengine: xilinx:
>dpdma: Add the Xilinx DisplayPort DMA engine driver
>> date:   4 weeks ago
>> config: h8300-randconfig-m031-20200811 (attached as .config)
>> compiler: h8300-linux-gcc (GCC) 9.3.0
>>
>> If you fix the issue, kindly add following tag as appropriate
>> Reported-by: kernel test robot <lkp@intel.com>
>>
>> smatch warnings:
>> drivers/dma/xilinx/xilinx_dpdma.c:1172 xilinx_dpdma_synchronize()
>> error: double unlocked 'chan->vchan.lock' (orig line 1170)
>
>Unless I'm mistaken, this is a false positive. I'd appreciate if someone could check
>if I'm missing something obvious.

Please ignore this report. It is a false positive. 
We have changed the rule to avoid send out this warning type directly. Sorry for inconvenient.

Best Regards,
Hui

>
>> vim +1172 drivers/dma/xilinx/xilinx_dpdma.c
>>
>>   1140
>>   1141	/**
>>   1142	 * xilinx_dpdma_synchronize - Synchronize callback execution
>>   1143	 * @dchan: DMA channel
>>   1144	 *
>>   1145	 * Synchronizing callback execution ensures that all previously issued
>>   1146	 * transfers have completed and all associated callbacks have been called
>and
>>   1147	 * have returned.
>>   1148	 *
>>   1149	 * This function waits for the DMA channel to stop. It assumes it has been
>>   1150	 * paused by a previous call to dmaengine_terminate_async(), and that
>no new
>>   1151	 * pending descriptors have been issued with dma_async_issue_pending().
>The
>>   1152	 * behaviour is undefined otherwise.
>>   1153	 */
>>   1154	static void xilinx_dpdma_synchronize(struct dma_chan *dchan)
>>   1155	{
>>   1156		struct xilinx_dpdma_chan *chan = to_xilinx_chan(dchan);
>>   1157		unsigned long flags;
>>   1158
>>   1159		xilinx_dpdma_chan_stop(chan);
>>   1160
>>   1161		spin_lock_irqsave(&chan->vchan.lock, flags);
>>   1162		if (chan->desc.pending) {
>>   1163			vchan_terminate_vdesc(&chan->desc.pending->vdesc);
>>   1164			chan->desc.pending = NULL;
>>   1165		}
>>   1166		if (chan->desc.active) {
>>   1167			vchan_terminate_vdesc(&chan->desc.active->vdesc);
>>   1168			chan->desc.active = NULL;
>>   1169		}
>> > 1170		spin_unlock_irqrestore(&chan->vchan.lock, flags);
>>   1171
>> > 1172		vchan_synchronize(&chan->vchan);
>>   1173	}
>>   1174
>>
>
>--
>Regards,
>
>Laurent Pinchart
>_______________________________________________
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