tags 700899 + pending - patch kthxbye On lun, feb 18, 2013 at 05:30:54 -0500, Daniel Kahn Gillmor wrote: > Package: valgrind > Version: 1:3.8.1-1 > Severity: normal > Tags: patch > > If i link the simple program below with -lpthread, then valgrind > reports a block of 32 bytes still-reachable from calloc within > dlopen(). > > If i do not link with -lpthread, then valgrind reports no errors.
I've looked a bit into this, and it seems that the _dlerror_run() function
allocates a thread specific buffer which gets automatically freed once the
thread terminates. In fact when calling dlopen()/dlclose() inside a thread the
leak does not happen:
#include <dlfcn.h>
#include <pthread.h>
void *leak(void *a) {
void *x;
x = dlopen("/usr/lib/x86_64-linux-gnu/libm.so", RTLD_LOCAL | RTLD_NOW);
dlclose(x);
}
int main(int argc, char *argv[]) {
pthread_t t;
void *ret;
pthread_create(&t, NULL, leak, NULL);
pthread_join(t, &ret);
/* leak(NULL); */
return 0;
}
It seems a benign leak so adding a suppression shouldn't cause any problem. This
is the suppression I've added (yours is a little bit too specific):
{
dlopen() with -lpthread bug#700899
Memcheck:Leak
fun:calloc
fun:_dlerror_run
fun:dlopen@@GLIBC_2.2.5
}
Cheers
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