Le 03/04/2012 23:13, Bob Friesenhahn a écrit : > On Tue, 3 Apr 2012, Brice Goglin wrote: >> >> I am fixing leaks in one of my software projects that embeds libltdl >> 2.4.2 to load plugins. I noticed that when the plugin depends on the >> dynamic library that the main program doesn't depend on, valgrind >> reports some leaks. > > If the main program is directly linked with -lpthread do some leaks go > away (or more are added)?
Everything goes away, but a new one appears. Anyway, see below. > >> We created a small testcase reproducing the problem. It's available at >> http://www.open-mpi.org/~jsquyres/ltdl-valgrind-leaks/ >> Just download it, ./configure, make, make install and then run valgrind >> as shown below. >> >> If we remove the reference to pthread in the plugin, the leaks go away. >> >> I assume that libltdl doesn't unload these dependency libraries when the >> plugin is unloaded. But I'd like to know if these leaks are expected or >> not. The good news is that these leaks do not depend on the number of >> times this code is executed within the program, so the leaked size >> should be constant. > > These reported leaks seem to be due to the glibc implementation and > don't look like libltdl's fault. It is interesting to me that these > reported leaks are different than I have seen before. Usually I see > leaks reported for thread-specific errno and thread specific data. > > It is common for glibc to secretly allocate some memory for its own > use, and this is particularly true for multi-threaded programs. Often > it has no way to safely release this memory. I tried with another dependency (libpci instead of libpthread), the leaks go away, so indeed the problem is likely outside of libltdl. Thanks and sorry for the noise! Brice _______________________________________________ https://lists.gnu.org/mailman/listinfo/libtool
