In message: Re: [linux-yocto][linux-yocto 
v5.10/standard/sdkv5.4/xlnx-soc][PATCH 2/2] dmaengine: xilinx: dpdma: 
request_irq after initializing dma channels
on 29/04/2021 Michal Simek wrote:

> 
> 
> On 4/29/21 9:46 AM, [email protected] wrote:
> > From: Quanyang Wang <[email protected]>
> > 
> > In some scenarios (kdump), dpdma hardware irqs has been enabled when
> > calling request_irq in probe function, and then the dpdma irq handler
> > xilinx_dpdma_irq_handler is invoked to access xdev->chan[i]. But at
> > this moment xdev->chan[i] hasn't been initialized. So let's call the
> > request_irq after initializing dma channels to avoid kdump kernel
> > crash as below:
> > 
> > [    3.696128] Unable to handle kernel NULL pointer dereference at virtual 
> > address 000000000000012c
> > [    3.696710] xilinx-zynqmp-dpdma fd4c0000.dma-controller: Xilinx DPDMA 
> > engine is probed
> > [    3.704900] Mem abort info:
> > [    3.704902]   ESR = 0x96000005
> > [    3.704905]   EC = 0x25: DABT (current EL), IL = 32 bits
> > [    3.704907]   SET = 0, FnV = 0
> > [    3.704912]   EA = 0, S1PTW = 0
> > [    3.713800] ahci-ceva fd0c0000.ahci: supply ahci not found, using dummy 
> > regulator
> > [    3.715585] Data abort info:
> > [    3.715587]   ISV = 0, ISS = 0x00000005
> > [    3.715589]   CM = 0, WnR = 0
> > [    3.715592] [000000000000012c] user address but active_mm is swapper
> > [    3.715596] Internal error: Oops: 96000005 [#1] SMP
> > [    3.715599] Modules linked in:
> > [    3.715608] CPU: 0 PID: 0 Comm: swapper/0 Not tainted 
> > 5.10.0-12170-g60894882155f-dirty #77
> > [    3.723937] Hardware name: ZynqMP ZCU102 Rev1.0 (DT)
> > [    3.723942] pstate: 80000085 (Nzcv daIf -PAN -UAO -TCO BTYPE=--)
> > [    3.723956] pc : xilinx_dpdma_irq_handler+0x418/0x560
> > [    3.793049] lr : xilinx_dpdma_irq_handler+0x3d8/0x560
> > [    3.798089] sp : ffffffc01186bdf0
> > [    3.801388] x29: ffffffc01186bdf0 x28: ffffffc011836f28
> > [    3.806692] x27: ffffff8023e0ac80 x26: 0000000000000080
> > [    3.811996] x25: 0000000008000408 x24: 0000000000000003
> > [    3.817300] x23: ffffffc01186be70 x22: ffffffc011291740
> > [    3.822604] x21: 0000000000000000 x20: 0000000008000408
> > [    3.827908] x19: 0000000000000000 x18: 0000000000000010
> > [    3.833212] x17: 0000000000000000 x16: 0000000000000000
> > [    3.838516] x15: 0000000000000000 x14: ffffffc011291740
> > [    3.843820] x13: ffffffc02eb4d000 x12: 0000000034d4d91d
> > [    3.849124] x11: 0000000000000040 x10: ffffffc0112d2d48
> > [    3.854428] x9 : ffffffc0112d2d40 x8 : ffffff8021c00268
> > [    3.859732] x7 : 0000000000000000 x6 : ffffffc011836000
> > [    3.865036] x5 : 0000000000000003 x4 : 0000000000000000
> > [    3.870340] x3 : 0000000000000001 x2 : 0000000000000000
> > [    3.875644] x1 : 0000000000000000 x0 : 000000000000012c
> > [    3.880948] Call trace:
> > [    3.883382]  xilinx_dpdma_irq_handler+0x418/0x560
> > [    3.888079]  __handle_irq_event_percpu+0x5c/0x178
> > [    3.892774]  handle_irq_event_percpu+0x34/0x98
> > [    3.897210]  handle_irq_event+0x44/0xb8
> > [    3.901030]  handle_fasteoi_irq+0xd0/0x190
> > [    3.905117]  generic_handle_irq+0x30/0x48
> > [    3.909111]  __handle_domain_irq+0x64/0xc0
> > [    3.913192]  gic_handle_irq+0x78/0xa0
> > [    3.916846]  el1_irq+0xc4/0x180
> > [    3.919982]  cpuidle_enter_state+0x134/0x2f8
> > [    3.924243]  cpuidle_enter+0x38/0x50
> > [    3.927810]  call_cpuidle+0x1c/0x40
> > [    3.931290]  do_idle+0x20c/0x270
> > [    3.934502]  cpu_startup_entry+0x28/0x58
> > [    3.938410]  rest_init+0xbc/0xcc
> > [    3.941631]  arch_call_rest_init+0x10/0x1c
> > [    3.945718]  start_kernel+0x51c/0x558
> > 
> > Fixes: 7cbb0c63de3f ("dmaengine: xilinx: dpdma: Add the Xilinx DisplayPort 
> > DMA engine driver")
> > Signed-off-by: Quanyang Wang <[email protected]>
> > ---
> >  drivers/dma/xilinx/xilinx_dpdma.c | 30 +++++++++++++++---------------
> >  1 file changed, 15 insertions(+), 15 deletions(-)
> > 
> > diff --git a/drivers/dma/xilinx/xilinx_dpdma.c 
> > b/drivers/dma/xilinx/xilinx_dpdma.c
> > index c4808a56aee0..7f37e23ede28 100644
> > --- a/drivers/dma/xilinx/xilinx_dpdma.c
> > +++ b/drivers/dma/xilinx/xilinx_dpdma.c
> > @@ -1744,19 +1744,6 @@ static int xilinx_dpdma_probe(struct platform_device 
> > *pdev)
> >     if (IS_ERR(xdev->reg))
> >             return PTR_ERR(xdev->reg);
> >  
> > -   xdev->irq = platform_get_irq(pdev, 0);
> > -   if (xdev->irq < 0) {
> > -           dev_err(xdev->dev, "failed to get platform irq\n");
> > -           return xdev->irq;
> > -   }
> > -
> > -   ret = request_irq(xdev->irq, xilinx_dpdma_irq_handler, IRQF_SHARED,
> > -                     dev_name(xdev->dev), xdev);
> > -   if (ret) {
> > -           dev_err(xdev->dev, "failed to request IRQ\n");
> > -           return ret;
> > -   }
> > -
> >     ddev = &xdev->common;
> >     ddev->dev = &pdev->dev;
> >  
> > @@ -1811,6 +1798,19 @@ static int xilinx_dpdma_probe(struct platform_device 
> > *pdev)
> >             goto error_of_dma;
> >     }
> >  
> > +   xdev->irq = platform_get_irq(pdev, 0);
> > +   if (xdev->irq < 0) {
> > +           dev_err(xdev->dev, "failed to get platform irq\n");
> > +           goto error_irq;
> > +   }
> > +
> > +   ret = request_irq(xdev->irq, xilinx_dpdma_irq_handler, IRQF_SHARED,
> > +                     dev_name(xdev->dev), xdev);
> > +   if (ret) {
> > +           dev_err(xdev->dev, "failed to request IRQ\n");
> > +           goto error_irq;
> > +   }
> > +
> >     xilinx_dpdma_enable_irq(xdev);
> >  
> >     xilinx_dpdma_debugfs_init(xdev);
> > @@ -1819,6 +1819,8 @@ static int xilinx_dpdma_probe(struct platform_device 
> > *pdev)
> >  
> >     return 0;
> >  
> > +error_irq:
> > +   of_dma_controller_free(pdev->dev.of_node);
> >  error_of_dma:
> >     dma_async_device_unregister(ddev);
> >  error_dma_async:
> > @@ -1827,8 +1829,6 @@ static int xilinx_dpdma_probe(struct platform_device 
> > *pdev)
> >     for (i = 0; i < ARRAY_SIZE(xdev->chan); i++)
> >             xilinx_dpdma_chan_remove(xdev->chan[i]);
> >  
> > -   free_irq(xdev->irq, xdev);
> > -
> >     return ret;
> >  }
> >  
> > 
> 
> I would wait reaction from Laurent and others on this. I expect it will
> come soon but no problem from my side.

Was this also submitted to them ? I didn't notice it on the mailing lists,
but could have easily missed it.

Quanyang: follow up to this patch when you get the rest of the feedback,
so I'll know it is good to merge.

Bruce

> 
> Thanks,
> Michal
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