[xml] race conditions in libxml2

[Hovnatan Karapetyan <hovnatan gmail com>]

Hi,

I have the following pretty simple program:

#include <stdlib.h>

#include <stdio.h>

#include <pthread.h>

#include <libxml/parser.h>

#include <libxml/catalog.h>

#include <libxml/tree.h>

#include <libxml/HTMLparser.h>

    

static const int kHTMLParseFlags = 

    HTML_PARSE_NOBLANKS | HTML_PARSE_NOERROR |           HTML_PARSE_NOWARNING | HTML_PARSE_NONET;

    

void* test1(void* ptr) {

    htmlDocPtr doc = htmlReadFile("http://www.google.com", NULL, kHTMLParseFlags);

    xmlFreeDoc(doc);

}

    

void* test2(void* ptr) {

    htmlDocPtr doc = htmlReadFile("http://www.lenta.ru", NULL, kHTMLParseFlags);

    xmlFreeDoc(doc);

}

int main(void)

{

    xmlInitParser();

    xmlInitializeCatalog();

    pthread_t thread1, thread2; 

    pthread_create(&thread1, NULL,  &test1, NULL);

    pthread_create(&thread2, NULL,  &test2, NULL);

    pthread_join(thread1, NULL);

    pthread_join(thread2, NULL);

    xmlCatalogCleanup();

    xmlCleanupParser();

    return EXIT_SUCCESS;

}

    

    

When I run it in `valgrind --tool=helgrind` it shows many race conditions. What is the reason for this? It seems that `libxml2` should be thread safe. I'm compiling with `gcc -I/usr/include/libxml2 temp.c -lxml2 -pthread`.

Thanks,

Hovnatan