Re: Help developing AD plugin

["Marco A. Barra Montevechi Filho via Tech-talk" <tech-talk at aps.anl.gov>]

That did it!

I see now, thanks for the tip. No segmentation fault anymore and when i make image plugin look at stripped NDWarp it loads the image in the visualizer normally.

Also, i mistakenly added some memory leak but solved it with  pOutput->release() after endProcessCallbacks

Many thanks!

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From: Mark Rivers <rivers at cars.uchicago.edu>
Sent: 16 August 2023 18:50
To: Marco A. Barra Montevechi Filho <marco.filho at lnls.br>; tech-talk at aps.anl.gov <tech-talk at aps.anl.gov>
Cc: SWC <swc at lnls.br>
Subject: RE: Help developing AD plugin

 

I believe I see your problem.  Your original code had these 2 lines:

 

    NDArray *pOutput;

 

    this->pNDArrayPool->copy(pArray, pOutput, true, true, true);

 

You created pOutput without setting it to NULL.  You then passed it to NDArrayPoolCopy.  If that pointer is not NULL then it is treated as a pointer to an existing array to modify.

 

You should change the code to this:

 

    pOutput = this->pNDArrayPool->copy(pArray, NULL, true, true, true);

 

NDArrayPool->copy is a function that returns the pointer to the new array.  It may be that NDWarp was creating pOutput and passing it to NDArrayPool->copy() which is OK, but your stripped down code was not doing that.

 

Mark

 

 

From: Marco A. Barra Montevechi Filho <marco.filho at lnls.br>
Sent: Wednesday, August 16, 2023 4:24 PM
To: Mark Rivers <rivers at cars.uchicago.edu>; tech-talk at aps.anl.gov
Cc: SWC <swc at lnls.br>
Subject: Re: Help developing AD plugin

 

I see! It seems to be null indeed:

Thread 146 "Warp1_Plugin_1" hit Breakpoint 1, NDPluginWarp::processCallbacks (this=0x558584ea99f0, pArray=0x7ff1480424c0)

    at ../NDPluginWarp.cpp:129

warning: Source file is more recent than executable.

129       NDPluginDriver::endProcessCallbacks(pOutput, true, true);

(gdb) x /p pArray->pData

0x7ff169270010:   Undefined output format "p".

(gdb) x %p pArray->pData

A syntax error in _expression_, near `%p pArray->pData'.

(gdb) print pArray

$1 = (NDArray *) 0x7ff1480424c0

(gdb) print pOutput

$2 = (NDArray *) 0x0

(gdb)

I blindly copied this from NDWarp but i could swear that NDWarp used this parameter as true...

Anyway, i changed it to true and now im having a segfault. I tried printing the address both via code and via gdb. I added:

NDArray *p;

to the code and

p = this->pNDArrayPool->copy(pArray, pOutput, true, true, true);

printf("%p\n",pOutput);

printf("%p\n",pArray);

I ran the IOC in gdb (Log appended in the end of this email) but it seems to me as a NULL pointer indeed.
What i dont understand is: NDWarp is looking at the SIM1 port from SimDetector. Why is copy failing?

The only thing i changed is that the frame size generated by ADSim is 3072x3072 pixels instead of 1024x1024. Should this matter?

GDB END LOG:

epics> [Thread 0x7f9f55267700 (LWP 13504) exited]

[Thread 0x7f9ff89c7700 (LWP 13503) exited]

[New Thread 0x7f9ff89c7700 (LWP 13506)]

[New Thread 0x7f9f55267700 (LWP 13507)]

[New Thread 0x7f9fa7b41700 (LWP 13508)]

[New Thread 0x7f9f55066700 (LWP 13509)]

[Thread 0x7f9f55066700 (LWP 13509) exited]

[Thread 0x7f9fa7b41700 (LWP 13508) exited]

[New Thread 0x7f9fa7b41700 (LWP 13510)]

[New Thread 0x7f9f55066700 (LWP 13511)]

[Thread 0x7f9fa7b41700 (LWP 13510) exited]

[Thread 0x7f9f55066700 (LWP 13511) exited]

a

(nil)

--Type <RET> for more, q to quit, c to continue without paging--

[Switching to Thread 0x7fa029d92b80 (LWP 13422)]

 

Thread 146 "Warp1_Plugin_1" hit Breakpoint 1, NDPluginWarp::processCallbacks (this=0x556321cd7930, pArray=0x7f9f3c0017a0) at ../NDPluginWarp.cpp:130

130       printf("%p\n",pArray);

(gdb) backtrace

#0  NDPluginWarp::processCallbacks (this=0x556321cd7930, pArray=0x7f9f3c0017a0) at ../NDPluginWarp.cpp:130

#1  0x00007fa02cb78b69 in NDPluginDriver::processTask (this=0x556321cd7930) at ../NDPluginDriver.cpp:524

#2  0x00007fa02c89545f in epicsThreadCallEntryPoint (pPvt=0x556321cd39a0) at ../../../src/libCom/osi/epicsThread.cpp:83

#3  0x00007fa02c89b4fb in start_routine (arg=0x556323c80530) at ../../../src/libCom/osi/os/posix/osdThread.c:403

#4  0x00007fa02ba9c609 in start_thread (arg=<optimized out>) at pthread_create.c:477

#5  0x00007fa02c77d133 in clone () at ../sysdeps/unix/sysv/linux/x86_64/clone.S:95

(gdb) frame 0

#0  NDPluginWarp::processCallbacks (this=0x556321cd7930, pArray=0x7f9f3c0017a0) at ../NDPluginWarp.cpp:130

130       printf("%p\n",pArray);

(gdb) info locals

info = {nElements = 9437184, bytesPerElement = 1, totalBytes = 9437184, colorMode = NDColorModeMono, xDim = 0, yDim = 1, colorDim = 0, xSize = 3072,

  ySize = 3072, colorSize = 0, xStride = 1, yStride = 3072, colorStride = 0}

pOutput = 0x0

p = <optimized out>

__PRETTY_FUNCTION__ = "virtual void NDPluginWarp::processCallbacks(NDArray*)"

---

From: Mark Rivers <rivers at cars.uchicago.edu>
Sent: 16 August 2023 17:56
To: Marco A. Barra Montevechi Filho <marco.filho at lnls.br>; tech-talk at aps.anl.gov <tech-talk at aps.anl.gov>
Cc: SWC <swc at lnls.br>
Subject: RE: Help developing AD plugin

 

Hi Marco,

 

Since you passed copyArray=false to endProcessCallbacks then it appears to me that the pArray you passed to that function must be NULL.

 

You should check the status return of NDArrayPool->copy() and you should print the value of the pOutput pointer returned from that function using the %p format.

 

Mark

 

 

 

From: Tech-talk <tech-talk-bounces at aps.anl.gov> On Behalf Of Marco A. Barra Montevechi Filho via Tech-talk
Sent: Wednesday, August 16, 2023 3:39 PM
To: tech-talk at aps.anl.gov
Cc: SWC <swc at lnls.br>
Subject: Help developing AD plugin

 

Hi all, we are developing a geometric restoration plugin here at Sirius for areaDetector

Im using NDWarp as a base just because it seems to work as a good example. Also, im unfortunately bound to EPICS 3.15.6, AreaDetector R3-7.

Taking NDWarp as a base, i basically stripped everything between NDPluginWarp::processCallbacks and NDPluginWarp::endProcessCallbacks, so the code is what i append at the end of this e-mail: it should only copy the original array that comes to it and pass it to the other connected plugins.

By compiling and running an IOC with this plugin, when i enable its callbacks i get the following message in my ioc shell:

2023/08/16 17:29:51.666 NDPluginDriver::endProcessCallbacks: Couldn't allocate output array. Further processing terminated.

Although i tried reading the source code, using gdb and recompiling ADCore by adding -g to USR_CXXFLAGS_Linux ad stepping into each function, etc. etc. i couldnt figure out what am i doing wrong. Am i passing a NULL array to  NDPluginDriver::endProcessCallbacks?

Are there any hints about this?

Thanks in advance,

Marco


CODE PART:

NDPluginWarp::processCallbacks(NDArray *pArray)

{

    // pArray is borrowed reference.  Caller will release()

 

    NDPluginDriver::beginProcessCallbacks(pArray);

 

    NDArrayInfo info;

    NDArray *pOutput;

    (void)pArray->getInfo(&info);

 

    if(pArray->ndims!=2 || info.xSize==0 || info.ySize==0) {

        asynPrint(pasynUserSelf, ASYN_TRACE_ERROR,

                  "%s:: 2D non-empty expected",

                  this->portName);

        return;

    }

    switch(pArray->dataType) {

    case NDInt8:

    case NDUInt8:

    case NDInt16:

    case NDUInt16:

    case NDInt32:

    case NDUInt32:

    case NDFloat32:

    case NDFloat64:

        break;

    default:

        asynPrint(pasynUserSelf, ASYN_TRACE_ERROR,

                  "%s:: Unsupported type %u",

                  this->portName, (unsigned)pArray->dataType);

        return;

    }

    asynPrint(pasynUserSelf, ASYN_TRACE_FLOW, "%s: %s ndarray=%p\n", this->portName, __PRETTY_FUNCTION__, pArray);

 

    printf("a\n");

    this->pNDArrayPool->copy(pArray, pOutput, true, true, true);

    NDPluginDriver::endProcessCallbacks(pOutput, false, true);

}

 

 

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