http://gcc.gnu.org/bugzilla/show_bug.cgi?id=52604
--- Comment #3 from Laurent Aflonsi <laurent.alfonsi at st dot com> 2012-03-20 12:31:31 UTC --- Well, in fact I am facing a runtime crash on another target (SH4). The crash is fixed by the patch proposed previously. On the other hand, I ve tried to reproduce on x86, to easily report on gcc bugs. and I ve discovered this valgrind error. I first thought both issues were the same, but they are not. And you are right, my patch doesn't fix the valgrind error. Sorry for confusion. The _M_thread_freelist might also be set to NULL at some point. (may be also in ~__freelist()). Setting _M_thread_freelist to NULL at ~__freelist() is solves the valgrind error, but I m not sure this is the right place to do it. Thanks