forked from rpms/glibc
		
	
		
			
				
	
	
		
			92 lines
		
	
	
		
			2.0 KiB
		
	
	
	
		
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			92 lines
		
	
	
		
			2.0 KiB
		
	
	
	
		
			Plaintext
		
	
	
	
	
	
PURPOSE of /tools/glibc/Regression/bz549813-dl-close-race-with-C-destructor
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Description: Test for bz549813 (dl_close() race with C++ destructor)
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Author: Petr Muller <pmuller@redhat.com>
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Bug summary: dl_close() race with C++ destructor
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Bugzilla link: https://bugzilla.redhat.com/show_bug.cgi?id=549813
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Description:
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This looks like a dup of
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http://sources.redhat.com/bugzilla/show_bug.cgi?id=654
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Create a pthread in the library init. In fini, cancel the pthread and then join. If the main thread does a dlclose(), the program hangs at pthread_join(). 
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It is stuck in a futex. I tried the testcase from http://sources.redhat.com/bugzilla/show_bug.cgi?id=654 and that fails too. 
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One thing that may be relevant is that if dlopen is called with RTLD_NODELETE, pthread_join will not hang.
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main program->
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#include <stdio.h> 
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#include <dlfcn.h> 
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int main(int argc, char *argv[]) {
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	void *handle;
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	handle =  dlopen("tiny.so",RTLD_NOW);
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	if (handle) 
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		printf("loaded shared library\n");
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	else {
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		printf("could not load shared library\n");
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		return (-1);
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	}	
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	sleep(1);
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	dlclose(handle);
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}
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the lib ->
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#include <pthread.h>
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#include <stdio.h>
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#include <unistd.h>
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#include <stdlib.h>
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#include <signal.h>
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pthread_t t;
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void *F(void *arg) {
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	int old;
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	if (pthread_setcancelstate(PTHREAD_CANCEL_ENABLE, &old) == 0) {
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		printf("> cancelability enabled.\n");
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	}
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	else {
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		printf("> could not set cancelability\n");
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		return (0);
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	}
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	sleep(2);
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} /*end F */
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int _init_rick (void) {
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printf("in init\n");
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    if (pthread_create(&t, NULL, (void *(*)(void *)) F, NULL) == 0) 
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	printf("started thread\n");
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else
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	printf("could not start thread\n");
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} /* end _init_rick */
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int _fini_rick (void) {
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	printf("in fini\n");
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	printf("canceling thread\n");
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	if (pthread_cancel(t) == 0)
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		printf("canceled thread\n");
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	else
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		printf("could not cancel thread \n");
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	printf("joining thread\n");
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	if (pthread_join(t, NULL) == 0)
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		printf("joined with thread\n");
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	else
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		printf("could not join with thread\n");
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} /* end _fini_rick */
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