In general the grammar pool implementation in xerces-c is not thread safe (i,e. access/storage of grammars). However, once a grammar is fully validated and stored, it needs to be immutable. So, it seems that we have a thread safety problem with the attributes list access. I'm looking into the problem.
Khaled
| Gareth Reakes <[EMAIL PROTECTED]>
03/02/2005 04:09 AM
|
|
Hey,
There have been a couple of bugs in Bugzilla relating to thread safety
of the grammars. I have not looked at them as yet. Khaled, are you out
there? Have you looked at the bugs?
Gareth
James Fitzgerald wrote:
>
> I am experimenting with the GrammarPool code and
> threads and am getting a crash.
>
> I create an XMLGrammarPool object and populate it
> with my schema. I lock it. I create 2 threads,
> instantiate a SAX2 parser in each thread and pass each
> the same pool and parse and validate a document in each
> thread. It crashes with a SEGV but runs fine when run
> in a single thread at a time.
>
> (gdb) bt
> #0 0xb7d053cd in
> xercesc_2_6::RefHash2KeysTableOfEnumerator<xercesc_2_6::SchemaAttDef>::findNext()
> (this=0x90cd348) at RefHash2KeysTableOf.c:549
> #1 0xb7d0643b in
> xercesc_2_6::RefHash2KeysTableOfEnumerator<xercesc_2_6::SchemaAttDef>::Reset()
> (this=0x90cd348) at RefHash2KeysTableOf.c:515
> #2 0xb7dd0954 in xercesc_2_6::SchemaAttDefList::Reset() (this=0x90cd320)
> at SchemaAttDefList.cpp:166
> #3 0xb7d02998 in xercesc_2_6::ComplexTypeInfo::getAttDefList() const (
> this=0x90cd040) at ComplexTypeInfo.cpp:433
> #4 0xb7d93100 in getAttDefList (isSchemaGrammar=true, currType=0x90cd040,
> elemDecl=0x922bf98) at IGXMLScanner2.cpp:3207
> #5 0xb7d8cff5 in
> xercesc_2_6::IGXMLScanner::buildAttList(xercesc_2_6::RefVectorOf<xercesc_2_6::KVStringPair>
> const&, unsigned, xercesc_2_6::XMLElementDecl*,
> xercesc_2_6::RefVectorOf<xercesc_2_6::XMLAttr>&) (this=0x80a2b10,
> [EMAIL PROTECTED], attCount=0, elemDecl=0x922bf98,
> [EMAIL PROTECTED]) at IGXMLScanner2.cpp:717
> #6 0xb7d9ab8a in xercesc_2_6::IGXMLScanner::scanStartTagNS(bool&) (
> this=0x80a2b10, [EMAIL PROTECTED]) at IGXMLScanner.cpp:2716
> #7 0xb7d96aab in xercesc_2_6::IGXMLScanner::scanContent() (this=0x80a2b10)
> at IGXMLScanner.cpp:886
> #8 0xb7d94d4a in
> xercesc_2_6::IGXMLScanner::scanDocument(xercesc_2_6::InputSource const&)
> (this=0x80a2b10, [EMAIL PROTECTED]) at IGXMLScanner.cpp:204
> #9 0xb7dc6e07 in
> xercesc_2_6::SAX2XMLReaderImpl::parse(xercesc_2_6::InputSource const&)
> (this=0x83c4c50, [EMAIL PROTECTED]) at SAX2XMLReaderImpl.cpp:647
> #10 0x0804f9fb in SAXProcessor::parse() (this=0x97b9700) at
> SAXProcessor.cpp:60
> #11 0x08050344 in client_thread(void*) (t=0x807a208) at prox.cpp:210
> #12 0xb7fc42b6 in start_thread () from /lib/tls/libpthread.so.0
> (gdb) l
> 544 //
> 545 // If there is a current element, move to its next element.
> If this
> 546 // hits the end of the bucket, the next block will handle
> the rest
> 547 //
> 548 if (fCurElem)
> 549 fCurElem = fCurElem->fNext;
> 550
> (gdb) p fCurElem
> warning: can't find class named
> `xercesc_2_6::RefHash2KeysTableOfEnumerator<xercesc_2_6::SchemaAttDef>',
> as given by C++ RTTI
> $1 = (RefHash2KeysTableBucketElem<xercesc_2_6::SchemaAttDef> *) 0x90cda48
> (gdb) p *fCurElem
> warning: can't find class named
> `xercesc_2_6::RefHash2KeysTableOfEnumerator<xercesc_2_6::SchemaAttDef>',
> as given by C++ RTTI
> $2 = {<XMemory> = {<No data fields>}, fData = 0x90cd968, fNext = 0x90cd300,
> fKey1 = 0x90cda00, fKey2 = 6}
> (gdb)
> (gdb) p *fCurElem->fNext
> warning: can't find class named
> `xercesc_2_6::RefHash2KeysTableOfEnumerator<xercesc_2_6::SchemaAttDef>',
> as given by C++ RTTI
> $3 = {<XMemory> = {<No data fields>}, fData = 0x90cd1a8, fNext = 0x0,
> fKey1 = 0x90cd240, fKey2 = 6}
> (gdb)
>
>
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--
Gareth Reakes, Managing Director Parthenon Computing
+44-1865-811184 http://www.parthcomp.com
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