Experimental Physics and
Industrial Control System

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<== Date ==>		<== Thread ==>

Subject:	RE: Crash in pvData
From:	Mark Rivers via Core-talk <[email protected]>
To:	'Michael Davidsaver' <[email protected]>
Cc:	"[email protected]" <[email protected]>
Date:	Sun, 30 Jun 2019 17:53:15 +0000

Hi Michael,

Thanks for the pointers.

Ø Could you add "fflush(stdout);" here? (or use stderr) stdout is buffered, and there may be additional output in the buffer when the crash occurs.

The fflush made no difference, I wonder if the process shutdown on Linux does a flush automatically? I've never seen a problem with missing printf output on crashes.

Ø That fact that this doesn't happen on the first or second iteration makes me wonder if this isn't a side-effect of memory corruption.

Ø Can you repeat this test running with valgrind?

I don’t think it has to do with memory corruption. I think it has to do with the somewhat unpredictable nature on the NDArrayPool. Some arrays in the pool will have the DataType attribute and some will not (yet) have it. It’s not deterministic which ones will and which won’t since it depends on the relative speeds of the different plugin threads.

Ø Also, the NTNDArrayConverter::fromAttribute() template needs a similar change.

Ø Though likely unrelated, there is a third unchecked cast in NTNDArrayConverter::getColorMode(),

Ø "int cm = static_pointer_cast<PVInt>(field->get())->get();", which should also be fixed.

I have added the checks and removed the static_casts in fromAttribute(), fromStringAttribute, and getColorMode().

The problem is now gone!

In order to handle the fact that valueFld in getAttribute can be different types I coded it as follows:

std::tr1::shared_ptr<pvAttrType> valueFld(destUnion->get<pvAttrType>());

This works, but I wonder if there is a cleaner way to do it that does not depend on the implementation of PVIntPtr, etc.?

This is the new code, still with the debugging printf() calls.

NDColorMode_t NTNDArrayConverter::getColorMode (void)

{

NDColorMode_t colorMode = NDColorModeMono;

PVStructureArray::const_svector attrs(m_array->getAttribute()->view());

for(PVStructureArray::const_svector::iterator it(attrs.cbegin());

it != attrs.cend(); ++it)

{

if((*it)->getSubField<PVString>("name")->get() == "ColorMode")

{

PVUnionPtr destUnion((*it)->getSubFieldT<PVUnion>("value"));

PVIntPtr valueFld(destUnion->get<PVInt>());

if(!valueFld)

throw std::runtime_error("ColorMode attribute is not of type PVInt");

int cm = valueFld->get();

colorMode = (NDColorMode_t) cm;

}

return colorMode;

}

template <typename pvAttrType, typename valueType>

void NTNDArrayConverter::fromAttribute (PVStructurePtr dest, NDAttribute *src)

{

valueType value;

src->getValue(src->getDataType(), (void*)&value);

PVUnionPtr destUnion(dest->getSubFieldT<PVUnion>("value"));

std::tr1::shared_ptr<pvAttrType> valueFld(destUnion->get<pvAttrType>());

if(!valueFld) {

valueFld = PVDC->createPVScalar<pvAttrType>();

destUnion->set(valueFld);

printf("NTNDArrayConverter::fromAttribute called destUnion->set() for %s\n", src->getName());

}

printf("NTNDArrayConverter::fromAttribute writing attribute %s\n", src->getName()); fflush(stdout);

valueFld->put(value);

printf("NTNDArrayConverter::fromAttribute wrote attribute %s OK\n", src->getName());

}

void NTNDArrayConverter::fromStringAttribute (PVStructurePtr dest, NDAttribute *src)

{

NDAttrDataType_t attrDataType;

size_t attrDataSize;

src->getValueInfo(&attrDataType, &attrDataSize);

std::vector<char> value(attrDataSize);

src->getValue(attrDataType, &value[0], attrDataSize);

PVUnionPtr destUnion(dest->getSubFieldT<PVUnion>("value"));

PVStringPtr valueFld(destUnion->get<PVString>());

if(!valueFld) {

valueFld = PVDC->createPVScalar<PVString>();

destUnion->set(valueFld);

printf("NTNDArrayConverter::fromStringAttribute called destUnion->set() for %s value=%s\n", src->getName(), &value[0]);

}

printf("NTNDArrayConverter::fromStringAttribute writing attribute %s value=%s\n", src->getName(), &value[0]); fflush(stdout);

valueFld->put(&value[0]);

printf("NTNDArrayConverter::fromStringAttribute wrote attribute %s OK\n", src->getName());

}

This is the complete debugging output when collecting 10 images. If you look for the string “called” you can see when it calls destUnion->set() in both fromAttribute() and fromStringAttribute().

ntNDArrayConverter::fromAttributes name=ColorMode dataType=4

NTNDArrayConverter::fromAttribute called destUnion->set() for ColorMode

NTNDArrayConverter::fromAttribute writing attribute ColorMode

NTNDArrayConverter::fromAttribute wrote attribute ColorMode OK

ntNDArrayConverter::fromAttributes name=SaveDest dataType=8

NTNDArrayConverter::fromStringAttribute called destUnion->set() for SaveDest value=Multiple

NTNDArrayConverter::fromStringAttribute writing attribute SaveDest value=Multiple

NTNDArrayConverter::fromStringAttribute wrote attribute SaveDest OK

ntNDArrayConverter::fromAttributes name=beam_x dataType=7

NTNDArrayConverter::fromAttribute called destUnion->set() for beam_x

NTNDArrayConverter::fromAttribute writing attribute beam_x

NTNDArrayConverter::fromAttribute wrote attribute beam_x OK

ntNDArrayConverter::fromAttributes name=beam_x_units dataType=8

NTNDArrayConverter::fromStringAttribute called destUnion->set() for beam_x_units value=mm

NTNDArrayConverter::fromStringAttribute writing attribute beam_x_units value=mm

NTNDArrayConverter::fromStringAttribute wrote attribute beam_x_units OK

ntNDArrayConverter::fromAttributes name=ColorMode dataType=4

NTNDArrayConverter::fromAttribute writing attribute ColorMode

NTNDArrayConverter::fromAttribute wrote attribute ColorMode OK

ntNDArrayConverter::fromAttributes name=SaveDest dataType=8

NTNDArrayConverter::fromStringAttribute writing attribute SaveDest value=Multiple

NTNDArrayConverter::fromStringAttribute wrote attribute SaveDest OK

ntNDArrayConverter::fromAttributes name=beam_x dataType=7

NTNDArrayConverter::fromAttribute writing attribute beam_x

NTNDArrayConverter::fromAttribute wrote attribute beam_x OK

ntNDArrayConverter::fromAttributes name=beam_x_units dataType=8

NTNDArrayConverter::fromStringAttribute writing attribute beam_x_units value=mm

NTNDArrayConverter::fromStringAttribute wrote attribute beam_x_units OK

ntNDArrayConverter::fromAttributes name=ColorMode dataType=4

NTNDArrayConverter::fromAttribute writing attribute ColorMode

NTNDArrayConverter::fromAttribute wrote attribute ColorMode OK

ntNDArrayConverter::fromAttributes name=DataType dataType=4

NTNDArrayConverter::fromAttribute called destUnion->set() for DataType

NTNDArrayConverter::fromAttribute writing attribute DataType

NTNDArrayConverter::fromAttribute wrote attribute DataType OK

ntNDArrayConverter::fromAttributes name=SaveDest dataType=8

NTNDArrayConverter::fromStringAttribute called destUnion->set() for SaveDest value=Multiple

NTNDArrayConverter::fromStringAttribute writing attribute SaveDest value=Multiple

NTNDArrayConverter::fromStringAttribute wrote attribute SaveDest OK

ntNDArrayConverter::fromAttributes name=beam_x dataType=7

NTNDArrayConverter::fromAttribute called destUnion->set() for beam_x

NTNDArrayConverter::fromAttribute writing attribute beam_x

NTNDArrayConverter::fromAttribute wrote attribute beam_x OK

ntNDArrayConverter::fromAttributes name=beam_x_units dataType=8

NTNDArrayConverter::fromStringAttribute called destUnion->set() for beam_x_units value=mm

NTNDArrayConverter::fromStringAttribute writing attribute beam_x_units value=mm

NTNDArrayConverter::fromStringAttribute wrote attribute beam_x_units OK

ntNDArrayConverter::fromAttributes name=ColorMode dataType=4

NTNDArrayConverter::fromAttribute writing attribute ColorMode

NTNDArrayConverter::fromAttribute wrote attribute ColorMode OK

ntNDArrayConverter::fromAttributes name=SaveDest dataType=8

NTNDArrayConverter::fromStringAttribute called destUnion->set() for SaveDest value=Multiple

NTNDArrayConverter::fromStringAttribute writing attribute SaveDest value=Multiple

NTNDArrayConverter::fromStringAttribute wrote attribute SaveDest OK

ntNDArrayConverter::fromAttributes name=beam_x dataType=7

NTNDArrayConverter::fromAttribute called destUnion->set() for beam_x

NTNDArrayConverter::fromAttribute writing attribute beam_x

NTNDArrayConverter::fromAttribute wrote attribute beam_x OK

ntNDArrayConverter::fromAttributes name=beam_x_units dataType=8

NTNDArrayConverter::fromStringAttribute called destUnion->set() for beam_x_units value=mm

NTNDArrayConverter::fromStringAttribute writing attribute beam_x_units value=mm

NTNDArrayConverter::fromStringAttribute wrote attribute beam_x_units OK

ntNDArrayConverter::fromAttributes name=ColorMode dataType=4

NTNDArrayConverter::fromAttribute writing attribute ColorMode

NTNDArrayConverter::fromAttribute wrote attribute ColorMode OK

ntNDArrayConverter::fromAttributes name=DataType dataType=4

NTNDArrayConverter::fromAttribute called destUnion->set() for DataType

NTNDArrayConverter::fromAttribute writing attribute DataType

NTNDArrayConverter::fromAttribute wrote attribute DataType OK

ntNDArrayConverter::fromAttributes name=SaveDest dataType=8

NTNDArrayConverter::fromStringAttribute called destUnion->set() for SaveDest value=Multiple

NTNDArrayConverter::fromStringAttribute writing attribute SaveDest value=Multiple

NTNDArrayConverter::fromStringAttribute wrote attribute SaveDest OK

ntNDArrayConverter::fromAttributes name=beam_x dataType=7

NTNDArrayConverter::fromAttribute called destUnion->set() for beam_x

NTNDArrayConverter::fromAttribute writing attribute beam_x

NTNDArrayConverter::fromAttribute wrote attribute beam_x OK

ntNDArrayConverter::fromAttributes name=beam_x_units dataType=8

NTNDArrayConverter::fromStringAttribute writing attribute beam_x_units value=mm

NTNDArrayConverter::fromStringAttribute wrote attribute beam_x_units OK

ntNDArrayConverter::fromAttributes name=ColorMode dataType=4

NTNDArrayConverter::fromAttribute writing attribute ColorMode

NTNDArrayConverter::fromAttribute wrote attribute ColorMode OK

ntNDArrayConverter::fromAttributes name=DataType dataType=4

NTNDArrayConverter::fromAttribute writing attribute DataType

NTNDArrayConverter::fromAttribute wrote attribute DataType OK

ntNDArrayConverter::fromAttributes name=SaveDest dataType=8

NTNDArrayConverter::fromStringAttribute writing attribute SaveDest value=Multiple

NTNDArrayConverter::fromStringAttribute wrote attribute SaveDest OK

ntNDArrayConverter::fromAttributes name=beam_x dataType=7

NTNDArrayConverter::fromAttribute writing attribute beam_x

NTNDArrayConverter::fromAttribute wrote attribute beam_x OK

ntNDArrayConverter::fromAttributes name=beam_x_units dataType=8

NTNDArrayConverter::fromStringAttribute writing attribute beam_x_units value=mm

NTNDArrayConverter::fromStringAttribute wrote attribute beam_x_units OK

ntNDArrayConverter::fromAttributes name=ColorMode dataType=4

NTNDArrayConverter::fromAttribute writing attribute ColorMode

NTNDArrayConverter::fromAttribute wrote attribute ColorMode OK

ntNDArrayConverter::fromAttributes name=DataType dataType=4

NTNDArrayConverter::fromAttribute writing attribute DataType

NTNDArrayConverter::fromAttribute wrote attribute DataType OK

ntNDArrayConverter::fromAttributes name=SaveDest dataType=8

NTNDArrayConverter::fromStringAttribute writing attribute SaveDest value=Multiple

NTNDArrayConverter::fromStringAttribute wrote attribute SaveDest OK

ntNDArrayConverter::fromAttributes name=beam_x dataType=7

NTNDArrayConverter::fromAttribute writing attribute beam_x

NTNDArrayConverter::fromAttribute wrote attribute beam_x OK

ntNDArrayConverter::fromAttributes name=beam_x_units dataType=8

NTNDArrayConverter::fromStringAttribute writing attribute beam_x_units value=mm

NTNDArrayConverter::fromStringAttribute wrote attribute beam_x_units OK

ntNDArrayConverter::fromAttributes name=ColorMode dataType=4

NTNDArrayConverter::fromAttribute writing attribute ColorMode

NTNDArrayConverter::fromAttribute wrote attribute ColorMode OK

ntNDArrayConverter::fromAttributes name=DataType dataType=4

NTNDArrayConverter::fromAttribute writing attribute DataType

NTNDArrayConverter::fromAttribute wrote attribute DataType OK

ntNDArrayConverter::fromAttributes name=SaveDest dataType=8

NTNDArrayConverter::fromStringAttribute writing attribute SaveDest value=Multiple

NTNDArrayConverter::fromStringAttribute wrote attribute SaveDest OK

ntNDArrayConverter::fromAttributes name=beam_x dataType=7

NTNDArrayConverter::fromAttribute writing attribute beam_x

NTNDArrayConverter::fromAttribute wrote attribute beam_x OK

ntNDArrayConverter::fromAttributes name=beam_x_units dataType=8

NTNDArrayConverter::fromStringAttribute writing attribute beam_x_units value=mm

NTNDArrayConverter::fromStringAttribute wrote attribute beam_x_units OK

ntNDArrayConverter::fromAttributes name=ColorMode dataType=4

NTNDArrayConverter::fromAttribute writing attribute ColorMode

NTNDArrayConverter::fromAttribute wrote attribute ColorMode OK

ntNDArrayConverter::fromAttributes name=DataType dataType=4

NTNDArrayConverter::fromAttribute writing attribute DataType

NTNDArrayConverter::fromAttribute wrote attribute DataType OK

ntNDArrayConverter::fromAttributes name=SaveDest dataType=8

NTNDArrayConverter::fromStringAttribute writing attribute SaveDest value=Multiple

NTNDArrayConverter::fromStringAttribute wrote attribute SaveDest OK

ntNDArrayConverter::fromAttributes name=beam_x dataType=7

NTNDArrayConverter::fromAttribute writing attribute beam_x

NTNDArrayConverter::fromAttribute wrote attribute beam_x OK

ntNDArrayConverter::fromAttributes name=beam_x_units dataType=8

NTNDArrayConverter::fromStringAttribute writing attribute beam_x_units value=mm

NTNDArrayConverter::fromStringAttribute wrote attribute beam_x_units OK

ntNDArrayConverter::fromAttributes name=ColorMode dataType=4

NTNDArrayConverter::fromAttribute writing attribute ColorMode

NTNDArrayConverter::fromAttribute wrote attribute ColorMode OK

ntNDArrayConverter::fromAttributes name=DataType dataType=4

NTNDArrayConverter::fromAttribute writing attribute DataType

NTNDArrayConverter::fromAttribute wrote attribute DataType OK

ntNDArrayConverter::fromAttributes name=SaveDest dataType=8

NTNDArrayConverter::fromStringAttribute writing attribute SaveDest value=Multiple

NTNDArrayConverter::fromStringAttribute wrote attribute SaveDest OK

ntNDArrayConverter::fromAttributes name=beam_x dataType=7

NTNDArrayConverter::fromAttribute writing attribute beam_x

NTNDArrayConverter::fromAttribute wrote attribute beam_x OK

ntNDArrayConverter::fromAttributes name=beam_x_units dataType=8

NTNDArrayConverter::fromStringAttribute writing attribute beam_x_units value=mm

NTNDArrayConverter::fromStringAttribute wrote attribute beam_x_units OK

Thanks,

Mark

-----Original Message-----
From: Michael Davidsaver <[email protected]>
Sent: Sunday, June 30, 2019 8:41 AM
To: Mark Rivers <[email protected]>
Cc: [email protected]
Subject: Re: Crash in pvData

On 6/29/19 2:06 PM, Mark Rivers wrote:

> ...

> That did not compile, so I changed it to this, i.e. replace

> destUnion->put() with destUnion->set() and value->put(value) with

> valueFld->put(&value[0])

oops. You're right of course. I was working from memory.

> I also added some debugging printfs.

> if(!valueFld) {

> valueFld = PVDC->createPVScalar<PVString>();

> destUnion->set(valueFld);

I'd be interested to know when this conditional is taken.

> }

> printf("Writing attribute %s value=%s\n", src->getName(), &value[0]);

Could you add "fflush(stdout);" here? (or use stderr) stdout is buffered, and there may be additional output in the buffer when the crash occurs.

> valueFld->put(&value[0]);

Also, have you tried simply commenting this line out?

> printf("Wrote attribute %s OK\n", src->getName());

> }

> I also have a printf in ntNDArrayConverter::fromAttributes the prints the name and datatype of each attribute as it iterates.

...

> Wrote attribute beam_x_units OK

> ntNDArrayConverter::fromAttributes name=ColorMode dataType=4

> ntNDArrayConverter::fromAttributes name=SaveDest dataType=8

> Writing attribute SaveDest value=Continuous

> Segmentation fault (core dumped)

That fact that this doesn't happen on the first or second iteration makes me wonder if this isn't a side-effect of memory corruption.

Can you repeat this test running with valgrind?

Also, the NTNDArrayConverter::fromAttribute() template needs a similar change.

Though likely unrelated, there is a third unchecked cast in NTNDArrayConverter::getColorMode(),

"int cm = static_pointer_cast<PVInt>(field->get())->get();", which should also be fixed.

> Note that it initially was working OK when there were only 4 attributes (ColorMode, SaveDest, beam_x, and beam_x_units). Only SaveDest and beam_x_units are string attributes (datatype=8), the others are epicsInt32 (datatype=4) and epicsFloat64 (datatype=7).

> After some time another attribute appears in the list, DataType. This is also epicsInt32. Shortly after that is added, but not immediately, there is an access violation writing SaveDest, which is a string attribute.

> This is the stack trace:

> #0 0x00007fd6e95cb2ad in () at /lib64/libstdc++.so.6

> #1 0x00007fd6e962ee5e in std::string::assign(std::string const&) ()

> at /lib64/libstdc++.so.6

> #2 0x00000000006c128d in

> epics::pvData::detail::ScalarStorageOps<std::string>::store(std::strin

> g const&) (__str="Continuous", this=0x7fd594002030)

> at /usr/include/c++/4.8.2/bits/basic_string.h:547

> #3 0x00000000006c128d in

> epics::pvData::detail::ScalarStorageOps<std::string>::store(std::strin

> g const&) (this=this@entry=0x7fd594002030, val="Continuous")

> at /usr/local/epics-devel/base-7.0.2/include/pv/pvData.h:362

> #4 0x00000000006cca5a in

> NTNDArrayConverter::fromStringAttribute(std::tr1::shared_ptr<epics::pv

> Data::PVStructure>, NDAttribute*) (v="Continuous",

> this=0x7fd594001fd0)

> at

> /corvette/usr/local/epics-devel/base-7.0.2/include/pv/pvData.h:399

> #5 0x00000000006cca5a in

> NTNDArrayConverter::fromStringAttribute(std::tr1::shared_ptr<epics::pv

> Data::PVStructure>, NDAttribute*) (this=this@entry=0x35481d0, dest=

> std::tr1::shared_ptr (count 3, weak 1) 0x7fd594001a70,

> src="" at ../ntndArrayConverter.cpp:544

> #6 0x00000000006cd06a in NTNDArrayConverter::fromAttributes(NDArray*)

> (this=this@entry=0x35481d0, src="" at

> ../ntndArrayConverter.cpp:591

> #7 0x00000000006cf66d in NTNDArrayConverter::fromArray(NDArray*)

> (this=0x35481d0, src="" at

> ../ntndArrayConverter.cpp:240

> #8 0x000000000066c6c8 in NTNDArrayRecord::update(NDArray*)

> (this=0x35459b0, pArray=0x7fd5640012b0) at ../NDPluginPva.cpp:85

> #9 0x000000000066c7fd in NDPluginPva::processCallbacks(NDArray*)

> (this=0x3504340, pArray=0x7fd5640012b0) at ../NDPluginPva.cpp:124

> #10 0x000000000066f5c6 in NDPluginDriver::processTask()

> (this=0x3504340) at ../NDPluginDriver.cpp:524

> #11 0x00000000012accc9 in epicsThreadCallEntryPoint(void*)

> (pPvt=0x3503090) at ../../src/osi/epicsThread.cpp:83

> #12 0x00000000012b273c in start_routine (arg=0x346a4c0) at

> ../../src/osi/os/posix/osdThread.c:403

> #13 0x00007fd6e9ed0e25 in start_thread () at /lib64/libpthread.so.0

> #14 0x00007fd6e8d89bad in clone () at /lib64/libc.so.6

> Line 544 is this line:

> valueFld->put(&value[0]);

> So it seems like this has not solved the problem?

> It seems like the previous function in NTNDArrayConverter may also have issues:

> template <typename pvAttrType, typename valueType>

> void NTNDArrayConverter::fromAttribute (PVStructurePtr dest,

> NDAttribute *src)

> {

> valueType value;

> src->getValue(src->getDataType(), (void*)&value);

> PVUnionPtr destUnion(dest->getSubField<PVUnion>("value"));

> if(!destUnion->get())

> destUnion->set(PVDC->createPVScalar<pvAttrType>());

> static_pointer_cast<pvAttrType>(destUnion->get())->put(value);

> }

> Is this also assuming that the datatype of that attribute has not changed?

> Thanks,

> Mark

> -----Original Message-----

> From: Michael Davidsaver <[email protected]>

> Sent: Saturday, June 29, 2019 10:48 AM

> To: Mark Rivers <[email protected]>; [email protected]

> Subject: Re: Crash in pvData

> On 6/29/19 7:37 AM, Mark Rivers via Core-talk wrote:

>> Folks,

>> I have an NDArray with a string attribute holding the value “Continuous”. When the NDArray gets converted to an NTNDArray in NTNDArrayConverter I am getting this crash:

>> #0 0x00007fad6f64e2ad in () at /lib64/libstdc++.so.6

>> #1 0x00007fad6f6b1e5e in std::string::assign(std::string const&) ()

>> at /lib64/libstdc++.so.6

>> #2 0x00000000006c113d in

>> epics::pvData::detail::ScalarStorageOps<std::string>::store(std::stri

>> n

>> g const&) (__str="Continuous", this=0x7fac14002650)

>> at /usr/include/c++/4.8.2/bits/basic_string.h:547

>> #3 0x00000000006c113d in

>> epics::pvData::detail::ScalarStorageOps<std::string>::store(std::stri

>> n

>> g const&) (this=this@entry=0x7fac14002650, val="Continuous")

>> at /usr/local/epics-devel/base-7.0.2/include/pv/pvData.h:362

>> #4 0x00000000006cbf41 in

>> NTNDArrayConverter::fromStringAttribute(std::tr1::shared_ptr<epics::p

>> v

>> Data::PVStructure>, NDAttribute*) (v="Continuous",

>> this=0x7fac140025f0)

>> at

>> /corvette/usr/local/epics-devel/base-7.0.2/include/pv/pvData.h:399

>> #5 0x00000000006cbf41 in

>> NTNDArrayConverter::fromStringAttribute(std::tr1::shared_ptr<epics::p

>> v

>> Data::PVStructure>, NDAttribute*) (this=this@entry=0x2fb0130, dest=

>> std::tr1::shared_ptr (count 3, weak 1) 0x7fac140020b0,

>> src="" at ../ntndArrayConverter.cpp:543

>> #6 0x00000000006ccc62 in

>> NTNDArrayConverter::fromAttributes(NDArray*)

>> (this=this@entry=0x2fb0130, src="" at

>> ../ntndArrayConverter.cpp:589

>> #7 0x00000000006cf38d in NTNDArrayConverter::fromArray(NDArray*)

>> (this=0x2fb0130, src="" at

>> ../ntndArrayConverter.cpp:240

>> #8 0x000000000066c578 in NTNDArrayRecord::update(NDArray*)

>> (this=0x2fad910, pArray=0x7fac94001270) at ../NDPluginPva.cpp:85

>> #9 0x000000000066c6ad in NDPluginPva::processCallbacks(NDArray*)

>> (this=0x2f6c2a0, pArray=0x7fac94001270) at ../NDPluginPva.cpp:124

>> #10 0x000000000066f476 in NDPluginDriver::processTask()

>> (this=0x2f6c2a0) at ../NDPluginDriver.cpp:524

>> #11 0x00000000012ac7f9 in epicsThreadCallEntryPoint(void*)

>> (pPvt=0x2f6aff0) at ../../src/osi/epicsThread.cpp:83

>> #12 0x00000000012b226c in start_routine (arg=0x2f6aeb0) at

>> ../../src/osi/os/posix/osdThread.c:403

>> #13 0x00007fad6ff53e25 in start_thread () at /lib64/libpthread.so.0

>> #14 0x00007fad6ee0cbad in clone () at /lib64/libc.so.6

>> This is base 7.0.2.2 on linux-x86_64.

>> Any idea why this is crashing?

> I first suspect static cast in

> NTNDArrayConverter::fromStringAttribute()

> https://github.com/areaDetector/ADCore/blob/44b3a9b62e65f8a8bfb180292f

> 77d08a5e2c4fdd/ADApp/ntndArrayConverterSrc/ntndArrayConverter.cpp#L535

> -L544

> From the logic, this code will break if the union already contains something which isn't a PVString.

> Assuming that the value should always be stored as a string (as opposed to attempting a conversion). Maybe change to something like:

>> std::vector<char> value(attrDataSize); // same as malloc(), with

>> auto-free()

>> src->getValue(attrDataType, &value[0], attrDataSize);

>> PVUnionPtr destUnion(dest->getSubFieldT<PVUnion>("value")); // note

>> the added T PVStringPtr valueFld(destUnion->get<PVString>());

>> if(!valueFld) {

>> valueFld = PVDC->createPVScalar<PVString>();

>> destUnion->put(valueFld);

>> }

>> value->put(value);

References:: Crash in pvData Mark Rivers via Core-talk; Re: Crash in pvData Michael Davidsaver via Core-talk; RE: Crash in pvData Mark Rivers via Core-talk; Re: Crash in pvData Michael Davidsaver via Core-talk

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Experimental Physics and Industrial Control System

Experimental Physics and
Industrial Control System